from:"Frank W. Zammetti"

You should be aware that IFrames are an IE-only thing.  Won't work on 
any other browser AFAIK.

What did you get when you tried onLoad()?   Maybe I can gelp get that 
working.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Jonathan Wilson wrote:
Just an FYI: I was unable to get the body onLoad() to work properly on 
both IE5 and Mozilla  - forget exactly why but it was supposed to work! 
Anyway, I instead used an IFRAME (internal frame) which I added to my 
forms' output stream(the same form the user just clicked submit() on - 
essentially a reload with new status information updated and a 
tad-bit-o-extra-output). The little-bit-o-code is below:

iframe name=thisIFRAME id=thisIFRAME src=get_doc?key_id=1668 
frameBorder=0 width=0 scrolling=no height=0/iframe

This creates a hidden(I don't want to argue the metaphysical side of 
this) window which in effect 'clicks' on the link I created. Works 
nicely...so far.
I'm not a HTML/Javascript guru so I can't tell you how long this trick 
will work.

Good luck
--Jonathan
Justin Ruthenbeck wrote:
At 12:17 PM 11/1/2004, you wrote:
I am not sure what you are refering to as atypical or robustness...

I meant to say that you could approximate the behavior you were asking 
for (dual response), but doing so would be hackish.

How do other sites generate files on the fly (take it out of a 
database, or a report just run), on form submit, and send them down 
the line and not run into this problem?

Like fzlists said, you'll see most sites load a page in response to a 
download request which either provides a link which the user can click 
on to download the binary content (right click, save as in IE), or 
that scripts the browser to automatically begin downloading.  This is 
how CNet, Yahoo, and others do this.

I see many people posting many places on the net that they are using 
the response to send a file, a lot of them are getting this 
IllegalState, but I never really found a followup solution that 
really fit my needs.

Why would the possibility exist to push a file through the response 
if it leaves you with the ability to go nowhere after?

If your browser submits a request and the response is a mp3 (through 
either URL inspection or Content-Disposition header), the browser will 
prompt the user to Save/Open/Run/whatever the file (and won't try to 
display it).  Once the file has been saved, it will leave you at the 
original page from which the file was requested.

Point being that after you push binary content through the response, 
it leaves you with whatever the previous page's options were ... 
there's really no contradiction in doing so.

justin

-Original Message-
From: Justin Ruthenbeck [mailto:[EMAIL PROTECTED]
Sent: Monday, November 01, 2004 2:56 PM
To: Tomcat Users List
Subject: Re: Response and file downloads

Luc,
At 11:42 AM 11/1/2004, you wrote:
I am having a wee problem with using the response.

I have a form on a page, with a submit button to download a file. That
file is being pulled from a database and pushed to the response.
The problem I am having, I just used that response to submit the page,
so I am getting and IllegalStateException, even though it is still
pushing the file to the browswer
I also want to be able to send a redirect after the file is downloaded
(so I can refresh the page so the form submit page is regenerated, 
since
we are using a string to determine unique submits are only coming from
the pages we generated, and not the browser address bar)

Can we get a new response from the session variable (the one available
to jsp writing) to send the file, then get another new response to
perform a redirect
Basically I want to be able to do something like

the form submits, and passes to the applications perform methods 
through
the jsp catching the submit
response = new Response
response.sendFile
response = new Response
response.sendRedirect
(yes I know those are not actual methods and classes, just trying to
explain what I want)

Your understanding of how, exactly, the http protocol works is
incorrect.  Because it is a (single) request, (single) response 
protocol,
what you're asking for cannot be done.

It seems like what you want is for a user to fill out a form, click
submit, then be presented with a new, fresh, form again ... with the 
file
download on the side.  If you have determined that you absolutely want
this behavior (it's atypical, so doing it won't be particularly robust),
consider programmatically opening another browser window on form submit
from which the download will happen ... and reload your form in your
main browser window.  This will, of course, subject you to any
headaches associated with javascipt window opening.

justin

__
Justin Ruthenbeck
Lead Software Engineer, NextEngine Inc.
justinr - AT - nextengine DOT com
Confidential. See:
http://www.nextengine.com/confidentiality.php

Re: Response and file downloads

It *is* possible that Mozilla now supports iFrames, I haven't kept up 
with it's development.  I do know for sure that they were originally an 
IE-only extension, so if Mozilla does support it, it represents a very 
rare case of Microsoft leading the pack :)

I'm not sure about the object tag idea... I've never seen it used that 
way but that certainly doesn't mean it won't work.   My understanding is 
that it embeds content in a page that is recognized by one plug-in or 
another... I suspect it wouldn't help in this case, but I could be wrong.

Now, if there is a way that I don't know about to target a layer, that 
could do the trick.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
David Wall wrote:
You should be aware that IFrames are an IE-only thing.  Won't work on
any other browser AFAIK.

Is that true?  My impression is that iframes work on Mozilla, too.  Anyway,
I think you can accomplish the same thing as an IFRAME using an OBJECT tag,
so that may be another way to return a page that instructs the client to
automatically issue the GET to download the file when the page is returned.
David
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Re: Response and file downloads

Hassan Schroeder wrote:
Dude, you need to get out more :-)  
Wife, kids, house, day job, my own company off-hours... Getting out 
hasn't happened much for about eight years now :)

IFRAME is part of the HTML 4.0
spec: http://www.w3.org/TR/html4/present/frames.html#edef-IFRAME
Cool, I didn't realize that.  Maybe it was just that support for it was 
not universal until relatively recently.  The last time I did any non-IE 
development frankly was about 3-4 years ago, obviously much could have 
changed since then.

And you can use OBJECT to include anything -- text files, HTML files,
images, whatever; if it's a browser-native format, it'll just be
displayed.
Something like this:
object
type=text/html data=alert-js.html
height=100px width=300px
/object
:: will include the page referenced as data.
That's definitely cool too, I never would have thought to even try it. 
I assume an object is available through DOM... does it have a src 
attribute?  You know what I'm getting at: dynamic changing of the 
content.  If that's possible, any idea how universal that would be?

Still, the most reliable solution for the problem at hand is probably
the META refresh...
No argument here :)
--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
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Re: Response and file downloads

Yeah, even though I don't do much non-IE work these days, the other 
browsers are at worst comparable (and many would say have far exceeded 
IE).  If you stick to standards-compliant code, there tends to be not 
much difficulty writing cross-browser code these days.  I think there's 
still enough difference in how things are rendered to make it 
unpleasant, but it's not nearly as difficult as it used to be.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Chad Maniccia wrote:
IE 4 made Netscape 4 look like a piece of crap. It was light-years
ahead.
I'm getting the impression that the other browsers have caught up but I
refuse to develop for them unless made to.
Questions:
Have the other browsers caught up with ease and power of their
scripting?
Do any of them have an XMLHTTP equivalent?
Do they share a common DOM?
I hate writing cross browser code. Supporting multiple browsers is like
having to test and write every application in Java, VB, and C.
Chad
-Original Message-
From: Frank W. Zammetti [mailto:[EMAIL PROTECTED] 
Sent: Monday, November 01, 2004 5:29 PM
To: Tomcat Users List
Subject: Re: Response and file downloads

It *is* possible that Mozilla now supports iFrames, I haven't kept up 
with it's development.  I do know for sure that they were originally an 
IE-only extension, so if Mozilla does support it, it represents a very 
rare case of Microsoft leading the pack :)

I'm not sure about the object tag idea... I've never seen it used that 
way but that certainly doesn't mean it won't work.   My understanding is

that it embeds content in a page that is recognized by one plug-in or 
another... I suspect it wouldn't help in this case, but I could be
wrong.

Now, if there is a way that I don't know about to target a layer, that 
could do the trick.



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Re: DataSource and initialContext.lookup(java:comp/env)

2004-11-06 Thread Frank W. Zammetti

I'll give it a shot...
All JNDI resource lookups occur relative to some context.  The code you 
posted first gets the default initial context, then looks for a resource 
named java:comp/env relative to that default context.  It then gets a 
reference to a DataSource that exists within the context jdbc/wms 
relative to java:comp/env

You can ROUGHLY think of this the same way you do URLs... in a sense, 
the java:comp/env might be something like www.apache.org.  That gives 
you a starting context.  Then if you want to retrieve a particular file 
in that domain, you look it up relative to the domain (i.e., 
www.apache.org/tomcat.htm).

Same thing here... There is a hierarchy of JNDI resources, a tree 
structure, that has an initial context as the root.  You then are in a 
sense constructing a path to your DataSource, and it might look 
something like /initial_context/java:comp/env/jdbc/wms (not exactly, but 
you get the idea).

Does that help any?
--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Eric Wulff wrote:
I just returned from working on a tutorial at sun which I was inspired
to go over based on my lack of understanding of the code snippet
below.  I'm trying to fully understand what's going on.  Docs state
that the code...
initialContext.lookup(java:comp/env) 

returns a named object.  Best I can tell is that this is a reference
to a starting point in my directory... or something like that.  Is
anyone willing to explain what initialContext.lookup() fundamentally
takes care of when called?
Context initialContext = new InitialContext();
Context context = (Context) initialContext.lookup(java:comp/env);
DataSource dataSource = (DataSource) context.lookup(jdbc/wms);
thx
Eric
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Re: can any one suggest me port number! 8080 is already used by Oracle9i's http server

2004-11-06 Thread Frank W. Zammetti

Aside from 8080, 8181 is a pretty typical port to use.  There's no rules 
or anything, virtually any port that isn't one of the well-known ports 
would be fine, but those two you tend to see used quite a bit.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Harry Douglass, Jr. wrote:
Port 9090 will work.
-Original Message-
From: Raasi Potluri [mailto:[EMAIL PROTECTED] 
Sent: Saturday, November 06, 2004 7:38 PM
To: [EMAIL PROTECTED]
Subject: can any one suggest me port number! 8080 is already used by
Oracle9i's http server

Dear Friends, Many thanks to read this email. well I
have installed Oracle 9i database on my PC and it has
got its own Apache Http server at port 8080, by
default. Now I'm trying to install Tomcat5.0.28
version and installation process gives me port number
conflict please tell me what shall I do, anybody
suggest me any other port number where I can install
Tomcat bcoz i dont want to amend the oracle's usage of
port 8080, regards, Raasi, 

		
__ 
Do you Yahoo!? 
Check out the new Yahoo! Front Page. 
www.yahoo.com 
 

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Re: DataSource and initialContext.lookup(java:comp/env)

2004-11-07 Thread Frank W. Zammetti

java:comp/env is the default namespace defined by JNDI.  The call to 
lookup() with this as an argument is returning an instance of a context 
corresponding to that namespace, which you need to do a further lookup 
for your specific resource.

On a related note, I'm pretty sure you could condense all the code you 
have to just one line, something like:

DataSource ds = (DateSource)new 
InitialContext().lookup(java:comp/env/jdbc/wms)

I'm fairly certain that works.  That might be clearer to you.
--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Eric Wulff wrote:
helpful somewhat...  at least in helping me narrow my question.  So
what is this java:comp/env?  What exactly is being returned based on
this string passed to lookup()?
Eric
On Sat, 06 Nov 2004 23:35:34 -0500, Frank W. Zammetti
[EMAIL PROTECTED] wrote:
I'll give it a shot...
All JNDI resource lookups occur relative to some context.  The code you
posted first gets the default initial context, then looks for a resource
named java:comp/env relative to that default context.  It then gets a
reference to a DataSource that exists within the context jdbc/wms
relative to java:comp/env
You can ROUGHLY think of this the same way you do URLs... in a sense,
the java:comp/env might be something like www.apache.org.  That gives
you a starting context.  Then if you want to retrieve a particular file
in that domain, you look it up relative to the domain (i.e.,
www.apache.org/tomcat.htm).
Same thing here... There is a hierarchy of JNDI resources, a tree
structure, that has an initial context as the root.  You then are in a
sense constructing a path to your DataSource, and it might look
something like /initial_context/java:comp/env/jdbc/wms (not exactly, but
you get the idea).
Does that help any?
--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

Eric Wulff wrote:
I just returned from working on a tutorial at sun which I was inspired
to go over based on my lack of understanding of the code snippet
below.  I'm trying to fully understand what's going on.  Docs state
that the code...
initialContext.lookup(java:comp/env)
returns a named object.  Best I can tell is that this is a reference
to a starting point in my directory... or something like that.  Is
anyone willing to explain what initialContext.lookup() fundamentally
takes care of when called?
Context initialContext = new InitialContext();
Context context = (Context) initialContext.lookup(java:comp/env);
DataSource dataSource = (DataSource) context.lookup(jdbc/wms);
thx
Eric
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Re: hide source of a page

2004-11-08 Thread Frank W. Zammetti

I had such a requirement at work one time, although fortunately I talked 
some sense into the higher-ups and they forgot about it, but not before 
I worked up an entire proof-of-concept document.  IN THEORY, this could 
make it very difficult for would-be hackers, although I wouldn't say 
fullproof.

The idea was to set up a frameset with one invisible frame and one 
full-screen frame.  Into the invisible frame would go an ActiveX control 
that was encrypted with a custom binary encrypter program (could be an 
applet too, but obfuscation isn't as good as encoding a binary). 
Basically, every form submission to the server would go through the 
control, and every response from the server would go through it, both 
encrypted.  On the response from the server, HTML is generated out of 
the control and placed into the frame in an obfuscated form.  Javascript 
it used to guard against right-clicks and keyboard shortcuts, and since 
the app starts up in it's own chromless window, it's relatively secure 
from most clientside exploits.  There is a handshake between the control 
and the server at startup that basically sets up a temporary 
public/private key pair, the point being to make it impossible to just 
issue commands via Telnet.  You'd have to fake considerably more than 
just some URLs or header variables.

So, the idea is that you could probably still get at the source, but it 
wouldn't be in cache so you'd probably have to use a memory scanner, but 
even if you did that it would be in an obfuscated form.  Not impossible 
to decypher, but probably hard enough that most people wouldn't both. 
Getting at the server is going to be difficult.  You could still 
decompile the control, but that's not going to be at all easy either 
considering the obfuscation and encryption (think a PE compactor approach).

I think making it tough is about as good as you can hope to do, but as 
Steven said, it's ALWAYS going to be defeatable one way or another.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Steven J. Owens wrote:
On Mon, Nov 08, 2004 at 09:37:09PM -0500, Dov Rosenberg wrote:
The only thing I can think of to hide the source of the page is to create
your own private label browser or perhaps load the source of the page in a
hidden frame and use some javascript to display the text you want. Not sure
why you would want to go thru the hassle - there are lots of ways to defeat
any measure.

 You're right, this is futile, because it's trivial to get the
source of the page, no matter what you do at the browser level.  The
browser has to see the source to render it, therefore the server is
providing the source, upon request, to anything that knocks at port 80
and asks for it.  Getting the source is as simple as telnetting to the
webserver on port 80 and faking the commands.  Or run a packet sniffer
in the network you're browsing from.  Or run a logging http proxy on
your own machine and point your browser at it.  

 You can't show something to people and keep it secret at the same
time.
 



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Re: hide source of a page

2004-11-08 Thread Frank W. Zammetti

No, there are actually plug-ins for other browsers to run ActiveX 
controls.  I don't know if they are particularly stable, but they do exist.

As I stated previously, you could use an applet, but obfuscating byte 
code is a futile task at best, whereas encrypting a binary executable is 
a little bit easier and gives a bit more security.  Not a lot mind you, 
but enough to matter.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Peter Johnson wrote:
But ActiveX is an IE only element is it not?
For that case why not just use an applet and serialise the data from 
Tomcat to the applet then either have JavaScript construct the page by 
querying the applet or have the applet be the interface.

Sunitha --- in short don't try.
PJ
Frank W. Zammetti wrote:
I had such a requirement at work one time, although fortunately I 
talked some sense into the higher-ups and they forgot about it, but 
not before I worked up an entire proof-of-concept document.  IN 
THEORY, this could make it very difficult for would-be hackers, 
although I wouldn't say fullproof.

The idea was to set up a frameset with one invisible frame and one 
full-screen frame.  Into the invisible frame would go an ActiveX 
control that was encrypted with a custom binary encrypter program 
(could be an applet too, but obfuscation isn't as good as encoding a 
binary). Basically, every form submission to the server would go 
through the control, and every response from the server would go 
through it, both encrypted.  On the response from the server, HTML is 
generated out of the control and placed into the frame in an 
obfuscated form.  Javascript it used to guard against right-clicks and 
keyboard shortcuts, and since the app starts up in it's own chromless 
window, it's relatively secure from most clientside exploits.  There 
is a handshake between the control and the server at startup that 
basically sets up a temporary public/private key pair, the point being 
to make it impossible to just issue commands via Telnet.  You'd have 
to fake considerably more than just some URLs or header variables.

So, the idea is that you could probably still get at the source, but 
it wouldn't be in cache so you'd probably have to use a memory 
scanner, but even if you did that it would be in an obfuscated form.  
Not impossible to decypher, but probably hard enough that most people 
wouldn't both. Getting at the server is going to be difficult.  You 
could still decompile the control, but that's not going to be at all 
easy either considering the obfuscation and encryption (think a PE 
compactor approach).

I think making it tough is about as good as you can hope to do, but as 
Steven said, it's ALWAYS going to be defeatable one way or another.


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Re: hide source of a page

2004-11-09 Thread Frank W. Zammetti

I said there are plug-ins for other browsers, not which browsers or how 
many browsers have them :)  In truth, I know that there was one for 
Netscape on Windows, and that's about it.  So, my statement was true, 
from a certain point of view (thank you Obi Wan!)

Seriously though, I couldn't tell you which browsers have such 
capability, and I seriously doubt they exist on Linux as another user 
mentioned (and the other poster was right, my company developers mostly 
highly-complex internal apps or apps used by our clients which are all 
forced to use IE on Windows only, so I have some flexibility others 
don't, although I don't have some flexibility others do, but that's a 
topic for another thread).  I do seem to recall seeing such a thing for 
Firefox on Windows, but I could be mistaken.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
David Stevenson wrote:
On 9/11/04 4:57, Frank W. Zammetti [EMAIL PROTECTED] wrote:

No, there are actually plug-ins for other browsers to run ActiveX
controls.  I don't know if they are particularly stable, but they do exist.

Can you show me one for Safari, and one for the Nokia 6310?
Thanks
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Re: Can I send response to browser even after the doGet returned?

2004-11-26 Thread Frank W. Zammetti

Couple of things...
No, I don't believe you can do anything with request/response after you
exit doGet(). Well, let me amend that... you MIGHT be able to get away
with it, but I wouldn't expect it to work all the time. What I mean is,
once your servlet is done it's work, the container takes over again, and
even if you do have a valid reference to the object, I wouldn't expect
that you could make any safe assumptions about the state of that object.
You might get away with it sometimes, but probably not every request.

The other point I wanted to make is that there is a pretty standard rule
against spawning threads to service requests. Simply stated, you aren't
supposed to do it. The container is supposed to spawn threads as
appropriate to service requests, and if your doing it on your own you
are more or less competing with the container. Bad Things (tm) tend
to happen under those circumstances.

I'm not really sure what you are trying to accomplish, but I'm taking a
guess that you think that by spawning the threads you will be able to
handle more requests concurrently. If that's not the case, please
explain you goals further.

But, assuming that is correct, I think you may have a fundamental
misunderstanding at work... A servlet is supposed to be thread-safe, and
the reason for that is that the container will spawn as many instances
of it as needed to service requests (to whatever configured limits there
are of course). In other words, every request essentially has it's own
thread executing your servlet, hence the need for it to be thread-safe.

In other words, you spwaning threads is superfluous because the
container is already doing essentially what your trying to do on your
own. So, just make sure your code is thread-safe, and your fine.

Or, are you trying to run some long-running process and think it would
be better off as it's own thread? If that's the case, you probably want
to look into some sort of queueing mechanism with either status polling
or some sort of callback when the task is complete. Again, more details
would be helpful.

As I said, I'm making assumptions here, so I could be completely wrong!
--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Santhosh Thomas wrote:

Hi
I know this is a basic question. I am passing the request and response object
to another thread from the doGet() and after that the Get method returns. So
that the processing is done in the thread and response to client will be
flushed later. But by that time the servlet method would have returned. My
question is, is it possible to flush the output to the client even after the
servlet method returned (or response is commited) by tomcat. I am not talking
about any server push but it is a simple http question.
If http does not support this, how can I implement this? can i do this by extending the generic servlet instead of HttpServlet?

Any help is greatly appreciated
thanks and regards
Boolee

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Re: Can I send response to browser even after the doGet returned?

2004-11-27 Thread Frank W. Zammetti

Has there any way to implement asynchronous request/response using 
servlets?

Not directly.  What you can do though is submit the request from the 
browser, put some operation in a queue and return immediately with a 
page that will call another servlet (or the same one, either way) to 
poll for the status of the queued operation.

There are packages out there to do such things without you having to 
build the functionality, but it's not a big deal to build it either. 
The bottom line though is that once your servlet completes, you cannot 
guarantee access to the request/response because the container will do 
what it will do with it.  That's almost certainly why, as you say 
yourself, sometimes you get a response and sometimes you don't.  The 
times you do is when your process finished before the container finished 
with the response, so you just got lucky, timing-wise.

Just queue the operation and let the browser poll for the status.  You 
don't have to show anything to the user that you don't want to either... 
Use a frameset.  In the main frame where the form is submitted from, 
just show a Please Wait message (as returned when the request was 
queued).  Then have a hidden frame that does the polling and updates the 
main frame when it's done.  That way, the user will just continue to see 
Please Wait until your ready for them to see something different.

Remember that anything asychronous pretty much boils down to two 
possible approaches: callbacks and polling.  You could do either 
(callback to an applet for instance), but polling is probably easier.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Dakota Jack wrote:
Why do you want to put the request in the queque?  I do something
similar in a messaging application that runs in the background.  I
have the message related matters bundled in an interface called
Message that is passed to the multithreaded queque.  Is there an
advantage to passing the request to the queque instead of something
engineered to handle that task?  I guess I have Frank's question: why,
why, why?  ;-)
Jack


On Sat, 27 Nov 2004 13:28:31 +0530, Santhosh Thomas
[EMAIL PROTECTED] wrote:
Or, are you trying to run some long-running process and think it would
be better off as it's own thread? If that's the case, you probably want
to look into some sort of queueing mechanism with either status polling
or some sort of callback when the task is complete. Again, more details
would be helpful.
No my process is not time consuming. It will finish in milliseconds and in 
the worst case can take a few seconds.  I am not spawning a thread from each 
servlet request, but the request processor is another independent 
thread(started at  web init) proecssing a queue of requests. I am only putting 
the request into the queue from doGet(). After putting into queue, the doGet() 
returns.  The request processor thread then forms the response and tries to 
flush the output later. My experience is, sometimes I get the output in the 
browser, sometimes not. I thought it was a broser catching problem (I am not 
sure..).
I cant do a polling in the servlet, bacause it will block my servlet.
Has there any way to implement asynchronous request/response using servlets?
thanks and regards
Santhosh
-
Couple of things...
No, I don't believe you can do anything with request/response after you
exit doGet(). Well, let me amend that... you MIGHT be able to get away
with it, but I wouldn't expect it to work all the time. What I mean is,
once your servlet is done it's work, the container takes over again, and
even if you do have a valid reference to the object, I wouldn't expect
that you could make any safe assumptions about the state of that object.
You might get away with it sometimes, but probably not every request.
The other point I wanted to make is that there is a pretty standard rule
against spawning threads to service requests. Simply stated, you aren't
supposed to do it. The container is supposed to spawn threads as
appropriate to service requests, and if your doing it on your own you
are more or less competing with the container. Bad Things (tm) tend
to happen under those circumstances.
I'm not really sure what you are trying to accomplish, but I'm taking a
guess that you think that by spawning the threads you will be able to
handle more requests concurrently. If that's not the case, please
explain you goals further.
But, assuming that is correct, I think you may have a fundamental
misunderstanding at work... A servlet is supposed to be thread-safe, and
the reason for that is that the container will spawn as many instances
of it as needed to service requests (to whatever configured limits there
are of course). In other words, every request essentially has it's own
thread executing your servlet, hence the need for it to be thread-safe.
In other words, you spwaning threads

Re: [HttpSession creation: When How]

2004-11-29 Thread Frank W. Zammetti

Yes, the session is created automagically when a servlet-served resource 
is accessed (meaning things other than HTML, images, things like that). 
 JSPs and servlets in other words.  I seem to remember a config switch 
to turn this off, but that's how it generally works, and this is usually 
how other app servers work too AFAIK.

There are ways to deal with the, the way I generally do it is simply to 
check for some known object in session.  This object is only placed in 
session from my logon process.  So, if it's not there at any other time, 
the user hasn't been validated.  Cue whatever error/redirection logic 
you want at that point.  I think this is a fairly typical approach.

This confused the hell out of me for a while too... It's a bit 
counterintuitive, especially when there exists API functionality to 
create a session or use an existing one.  The logic there I suppose is 
that you may want to discard the automatically-created session in favor 
of your own during a logon process for instance, but I'm not sure I see 
the reason for doing that.

In any case, you aren't seeing anything unusual here, it's simply 
something you have to deal with one way or another (or find out the 
config switch to turn it off, if my memory is serving me correctly in 
saying it exists at all).

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Carlos Cajina wrote:
Good evening.
My question is about HttpSession objects creation and destruction within 
a Servlet/JSP container. I'm using the JBoss/Tomcat bundle (versions 
3.2.3/4.1.29) with a database realm properly configured. Here's how 
things work so far:

1. User goes to a predefined Welcome File (index.html)
2. Within the welcome file there's a link to a protected resource (wich 
happens to be the application's main screen)
3. The user clicks the link and the login page appears.
4. The user enters login/password and logs on successfully or is 
redirected to an error page.

Up to this point everything works fine, but the thing that I don't 
understand is that the moment the user clicks the link that points to a 
protected resource an HttpSession object is created by the server even 
though the user hasn't been authenticated. This behavior kinda ruin my 
plans because I have a Session Creation/Destruction Listener that is 
supposed to detect a session creation event in order to be able to place 
some things (objects) in that user session, but it seems that the 
created session for the unauthenticated is recycled after 
authentication and my session lifecycle listener is no longer useful 
(the session already exists)

I've looked into the Servlet spec but couldn't find anything clarifying 
enough... I'f anyone has any comments, tips, thoughts on this issue I'd 
like to hear'em... :^)

Regards,
Carlos...
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Re: liberaries

2004-12-02 Thread Frank W. Zammetti

These are the basic servlet classes.  I usually just put j2ee.jar on the 
path, but there is also servlet-api.jar somewhere in /tomcat/common/lib. 
 Either one should do the trick.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
James Peterson wrote:
ok I am trying to recompile one of the examples that comes with tomcat and
whenI do I get the following errors.
Login.java:6: package javax.servlet does not exist
import javax.servlet.*;
^
Login.java:7: package javax.servlet.http does not exist
import javax.servlet.http.*;
where do I get these or how can I fix this?
--
James Peterson
Network Administrator
Roman Meal Milling Company
Phone 701.282.9656
Fax 701.282.9743
Email [EMAIL PROTECTED]
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RE: sending a JSP page by email

2004-12-16 Thread Frank W. Zammetti (MLists)

I *believe*, but don't hold me to it, that you can implement a filter
AFTER the JSP renders, in the latest servlet spec.  With that, you
shouldn't have much trouble taking the output stream and sending it as an
eMail.  I'd also assume, although I don't know for sure, that you could
basically kill the response at that point, so it's not trying to send
back to the client or anything.

-- 
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

On Thu, December 16, 2004 1:38 pm, haimra said:
 I had tried doing the same thing and failed.
 But after I gained more knowledge I had a new idea that I did not tried
 yet.
 I will be happy if you let me know if it works.

 The basic Idea is that if we used a servelet we had no problem taking the
 StringBuffer created and coping it into the mail message and not back to
 the
 browser.


 The problem with JSP, it's actually a servlet but we can not control it.
 In the Java Server Page (O'reilly page 315) book I found some directive
 element.

 %@ page buffer=12kb autoFlash=false %

 When autoFlash=false the JSP container will not flush the buffer until
 the
 following script % out.flash() % is used. Maybe there is a way to
 redirect
 this output writer to a buffer and email it.

 What do you think?
 Haim

 -Original Message-
 From: Gabriel Belingueres [mailto:[EMAIL PROTECTED]
 Sent: Wednesday, December 15, 2004 12:15 AM
 To: [EMAIL PROTECTED]
 Subject: sending a JSP page by email

 Hi,

 How can I take advantage of Tomcat's JSP processing engine to use a
 JSP page as a template for an email?

 That is, I want to do something like a page forwarding from a servlet,
 but this forwarding process the JSP page and, instead of send it to
 the browser, it send it by email to somebody.

 Thanks in advance,
 Gabriel

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[OT] Request an app test (free beer!)

2004-12-20 Thread Frank W. Zammetti

I was informed last OT post I made that the subject should always 
include the word beer.  I added the free to get your attention :)

I'm working on something for which I need to know what the os.name 
property on various OS's is.  I would greatly appreciate it if some 
folks could try the following:

public class test {
public static void main(String[] args) {
System.out.println(System.getProperty(os.name));
}
}
I'm particularly interested in various *nix variants, Linux, Mac and 
such.  Windows I already have answers for (although some verification to 
be sure nothing fishy is going on wouldn't hurt).

If you could just post your OS and what the result was, I would greatly 
appreciate it.  Thanks in advance!

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
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Re: How to run servlet for every 30 minutes in Tomcat 4.1.30

2004-12-21 Thread Frank W. Zammetti

It's interesting, Craig and I had an exchange about threads in servlet 
containers last week... I can't find a link to the thread unfortunately.

Anyway, the basic idea behind that don't spawn your own threads inside 
a servlet container admonishment is based more on the fact that it's 
quite easy to screw up doing so, more than it has to do with virtually 
anything else.

You want the servlet container to manager resources for you, and you 
lose that by spawning your own threads.  The container isn't aware of 
the threads, so it can't control them for things like graceful shutdowns 
or simply trying to control resource utilization.  Many people, 
including me, tend to ignore that warning when the situation warrants 
it, but you have to be extra-careful.

For instance, you don't under any circumstances want to hold on to 
references to response, request or session objects because you don't 
manage them.  You also, unless you really have a need and know what your 
doing, want to spawn threads to handle requests at all.  Any threads you 
do spawn in a container should tend to be independent units of 
execution.  If your use case fits that description, you can get away 
with it relatively safely.

That being said, spawning things like daemon threads for low-level 
behind-the-scenes type processing is generally OK, so long as you are 
careful (i.e., be sure no runaway processing can occur, make sure it 
will shut down gracefully, etc).  You might be able to use something 
like that in this case, you'll have to decide.  If your using Struts, 
you can spawn the thread from a plug-in, as I've done in the past, but 
there are non-Struts equivalents (worse comes to worse, just do it in a 
servlet.init()).  Do yourself a favor and make the thread processing 
functional independent of your app essentially, and even make it so it's 
not aware it's running in a servlet container.  But again, caution is 
the key.  If you make it a demon thread and set it's priority as low as 
you can and be sure to not hold on to a reference to it, I've found that 
works just fine under a number of app servers on a numeber of OSs.

The bottom-line is that really that psuedo-rule is around because people 
tend to shoot themselves in the foot when using threads a bit too often, 
so better to advise against getting into a situation where you might do 
that.  But, if your confident in your ability, and believe the use case 
really warrants it, you CAN do it, and relatively safely.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Dennis Payne wrote:
It is possible to create a servlet thread in the init() method.  That
thread sould stay alive and run something every thirty minutes.  The
issue of pushing information out to the user remins the same.  The
servlet and the thread cannot do that.  On the other hand, it is
possible to setup java script on the page to detect 30 minute intervals
to pull a page from the server.
It is an awful lot of work for so little a result... It is best just to
put a java process into cron or task scheduler and have the user run the
report when they want the info.

[EMAIL PROTECTED] 12-21-2004 14:44 
Jorge Sopena wrote:
Why is bad using own threads inside web application?
Aren't all the servlet request actually a thread in Tomcat?
I can't find a reason why it's so bad solution.

I think that comes from J2EE specs. I do not remember is threads just
forbidden but if you follow specs, you do not know and you do not have
to know how application server uses threads and controls thread 
behaviour. If portability is issue for your application, it is better
to
not use threads.

 
In that way, you manage to have a single and independent
application.
Maybe I don't know some thread behaviour in Tomcat...

After all, I have use threads in web application with tomcat :) and I 
haven't have any problems or strange thread behaviour. Sometimes whole

concurrent programming and syncronizing my own threads causes troubles
but nothing due tomcat.
Back to original question.

[EMAIL PROTECTED] wrote:
I am using Tomcat4.1.30 version.
I have to develop a client application which looks in the database
every 30
minutes,

ApplicationContextListener + Timer + TimerTask

to retrieve the status of an order and send the status to the remote
client.
Again waits for the
The client's response and insert the repsonse back to the database.

What is that remote client? Is actually another server and your 
application is client. If so, just add client code for server in 
TimerTask (http-, web service- or whatever client).

- Jukka -
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Re: How to run servlet for every 30 minutes in Tomcat 4.1.30

2004-12-21 Thread Frank W. Zammetti

Your just lending weight to what I said... Don't play with threads in a 
servlet contain unless your really sure you have to and are really sure 
you can do it safely :)

(I'm not sure I knew init() could be called more than once, certainly I 
didn't remember when I wrote that, so excellent point)

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
QM wrote:
On Tue, Dec 21, 2004 at 03:37:26PM -0700, Dennis Payne wrote:
: It is possible to create a servlet thread in the init() method.  That
: thread sould stay alive and run something every thirty minutes.
Yes and no. ;)
It's possible to use a servlet's init() method for this; but per the
spec, containers are free to initialize a servlet class as many times as
they see fit.
Much safer to use a ContextListener in this case, as those are triggered
only on app (context) startup and shutdown.
-QM


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Re: How to run servlet for every 30 minutes in Tomcat 4.1.30

Dennis Payne wrote:
Frank,
I'm using threads and didn't know I was vulnerable.  
I'm not sure vulnerable is really the right word, but I'll go with it :)
Here's how I've 
done it.  I created a class that implements runnable and call its 
initialize method from a servlet init method at application startup. 
 The initialize method creates a thread and sets a low priority for it.
Roughly what I do too, except that my class extends Thread and I kick it 
off from a Struts plug-in.  Same effect though.

 The run method sleeps the thread and wakes it every two minutes.
A processing class contains the methods that queries the database 
(postgres).
Same here.  I think I wake my threads every minute though.
1. Is this what you call a daemon thread?
Nope.  If you take a peak at the javadocs for the Thread class, you'll 
see a method setDaemon(boolean).  This marks a thread as a daemon 
thread.  The difference, if I remember correctly, is that the JVM won't 
shut down until all remaining threads are daemon threads.  Threfore, if 
you spawn a normal thread, you can hold up the JVM from shutting down 
properly.

This is in fact the situation I had... My Tomcat instance could never be 
properly shut down because the threads I had spawned where not daemon 
threads.  Marking them as such solved that problem.

To the best of my knowledge, being a daemon thread doesn't implicitly 
say anything about a threads priority.  I think you could have a daemon 
thread set at high priority if you wanted.  I suspect most daemon 
threads are bumped to a lower priority though, as I do.

2. Is this better done using cron?  if so how do I ensure that it runs
with a lower priority than my application code?
Phil
This is a matter of opinion, and there are some reasonable arguments for 
both points of view.

My personal opinion is that if you have some periodic process that is 
going to need portions of your system, whether it's resources available 
in the container or shared code, as you do, then a low-priority daemon 
thread spawned at application startup is a good approach, assuming you 
write it carefully and solidly.

For instance, in my case, my daemon threads do some record aging in the 
database, so to me it makes sense to share the same connection pool as 
the application itself.  I also use a number of classes and functions 
that are part of the webapp itself, and I don't like the idea of 
duplicating the code for a cron job to use (sure, could just be a matter 
of setting up a classpath to those classes, but it's an extra 
dependency, and that doesn't thrill me).

But, if these tasks were volatile in any way, or they had to run 
independently of the app itself no matter what, the cron job approach 
would probably be preferable.

As for ensuring it runs at a lower priority than your application code, 
when running via cron, that's an answer I can't give you.  I'm frankly a 
Unix newbie, more or less, so someone else out there would be better 
suited to answer that.  I think you'd have to have it run at a lower 
priority than your app server, and I'm sure there's switches to set 
priority of jobs, but I don't know them.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
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Re: JSP under /WEB-INF folder

I think his problem is probably linking to stylesheets and such... 
Actually, now I have to ask you... if you put *everything* under 
WEB-INF, I assume you are serving all graphics from a fronting web 
server then?  Otherwise, any document returned to the user that links 
back to a resource under WEB-INF won't be reachable, which was the crux 
of his problem as I understood it, that's why he was talking about 
includes and such all over the place.  But, if you really are serving 
everything from there, how are you doing it?  Just curious at this point :)

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Dakota Jack wrote:
I don't know why you are saying that css and/or js must be placed
directly under WebRoot.  Why do you?  I can give you various
solutions, once I find out what the problem is supposed to be.  There
is no issue, by the way, with putting your JSP files under WEB-INF. 
There are other ways to protect access, but this is, I think, a good
one too.

Jack
On Sun, 26 Dec 2004 22:31:32 +0800, Koon Yue Lam [EMAIL PROTECTED] wrote:
Hi, I want to protect my JSP from direct access, so they can only
access by Struts action.
but
If I want to include some Javascript or CSS to a JSP, I can't !
Because .js and .css needed to place directly under WebRoot
My solution is to use jps:include to include all those Javascript
and CSS to JSP, but then the JSP will look very ugly and fill up with
long long non HTML stuffs .. which is not so nice
Is there any any to solve this or I just need to accept this trade-off?
Any help would be appreciated
Regards
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Re: How to run servlet for every 30 minutes in Tomcat 4.1.30

I think what you describe is probably more properly implemented as some 
sort of queueing system.  Something along the lines of setting up a 
queue on each data collection server that lazily updates the central 
server (there's other ways to structure it of course).

Otherwise, I myself would tend towards a push model, since that's 
really more in line with how most web development is done.  So, have the 
data collection servers push the records to the central server instead, 
whether queues are involved or not.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
phil campaigne wrote:
Frank W. Zammetti wrote:
Dennis Payne wrote:
Frank,
I'm using threads and didn't know I was vulnerable.  

I'm not sure vulnerable is really the right word, but I'll go with 
it :)

Here's how I've done it.  I created a class that implements runnable 
and call its initialize method from a servlet init method at 
application startup.  The initialize method creates a thread and sets 
a low priority for it.

Roughly what I do too, except that my class extends Thread and I kick 
it off from a Struts plug-in.  Same effect though.

 The run method sleeps the thread and wakes it every two minutes.
A processing class contains the methods that queries the database 
(postgres).

Same here.  I think I wake my threads every minute though.
1. Is this what you call a daemon thread?

Nope.  If you take a peak at the javadocs for the Thread class, you'll 
see a method setDaemon(boolean).  This marks a thread as a daemon 
thread.  The difference, if I remember correctly, is that the JVM 
won't shut down until all remaining threads are daemon threads.  
Threfore, if you spawn a normal thread, you can hold up the JVM from 
shutting down properly.

This is in fact the situation I had... My Tomcat instance could never 
be properly shut down because the threads I had spawned where not 
daemon threads.  Marking them as such solved that problem.

To the best of my knowledge, being a daemon thread doesn't implicitly 
say anything about a threads priority.  I think you could have a 
daemon thread set at high priority if you wanted.  I suspect most 
daemon threads are bumped to a lower priority though, as I do.

2. Is this better done using cron?  if so how do I ensure that it runs
with a lower priority than my application code?
Phil

This is a matter of opinion, and there are some reasonable arguments 
for both points of view.

My personal opinion is that if you have some periodic process that is 
going to need portions of your system, whether it's resources 
available in the container or shared code, as you do, then a 
low-priority daemon thread spawned at application startup is a good 
approach, assuming you write it carefully and solidly.

For instance, in my case, my daemon threads do some record aging in 
the database, so to me it makes sense to share the same connection 
pool as the application itself.  I also use a number of classes and 
functions that are part of the webapp itself, and I don't like the 
idea of duplicating the code for a cron job to use (sure, could just 
be a matter of setting up a classpath to those classes, but it's an 
extra dependency, and that doesn't thrill me).

But, if these tasks were volatile in any way, or they had to run 
independently of the app itself no matter what, the cron job approach 
would probably be preferable.

As for ensuring it runs at a lower priority than your application 
code, when running via cron, that's an answer I can't give you.  I'm 
frankly a Unix newbie, more or less, so someone else out there would 
be better suited to answer that.  I think you'd have to have it run at 
a lower priority than your app server, and I'm sure there's switches 
to set priority of jobs, but I don't know them.

Frank,
I also am doing record aging.  I want to move records older than two 
minutes to a centralized server for processing.  Think of it as multiple 
data collection servers and a centralized data processing server.  I'm 
thinking that the daemon to schedule queries against the data collection 
servers should execute on the centralized server. 
I'm wonder if this form of light weight replication is a good practice. 
Does anyone have some insite on this?
Phil

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Re: Including jsp files that exist outside of the web application

You know, I'm not sure how often this comes up for people, but it might 
make a good custom tag... I can imagine simply a version of 
jsp:include that allows for absolute paths.  Sure, it'll tie you to an 
OS to some degree (i.e., change paths from Windows forms to Unix forms), 
but that might be something people can live with.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
[EMAIL PROTECTED] wrote:
On Tue, 28 Dec 2004, Dakota Jack wrote:

What if you don't include the JSP file but include the related JAVA
file and use CLASSPATH?  Will that work?  You cannot, of course, make
this dynamic, since you have class loader issues.  The biggest issue
is the class loader issue.  You might create a set of interfaces and
implemenations outside your web application that allow dynamic
reloading.  I don't see, however, why your edited files are not just
popped into your web application without issues?

We would love to be able to pop our edited files back into the web
application, but we don't see an easy way to do that.  The files must be
dynamic, as they will be edited many times over the lifetime of the
current web application.
So far, symbolic linking out of the web application seems to be the only
way we have found to really do this.
Thank you,
-Raiden
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JSP compilation problem

2004-12-30 Thread Frank W. Zammetti

)
  at
org.apache.catalina.core.StandardPipeline.invoke(StandardPipeline.java:520)
  at
org.apache.catalina.core.ContainerBase.invoke(ContainerBase.java:929)
  at
org.apache.coyote.tomcat5.CoyoteAdapter.service(CoyoteAdapter.java:160)
  at
org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:799)
  at
org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.processConnection(Http11Protocol.java:705)
  at
org.apache.tomcat.util.net.TcpWorkerThread.runIt(PoolTcpEndpoint.java:577)
  at
org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
  at java.lang.Thread.run(Thread.java:595)
One thing... it looks like the servlet got generated, just couldn't be 
compiled for some reason.  I can't figure out why though.  I'm not sure 
where the compiler error output referenced in the Catalina log is.

I've done some Googling for about an hour but haven't come up with 
anything helpful.  Any ideas?  I've confirmed JAVA_HOME is set properly, 
and I copied tools.jar to /common/lib, neither help.  Thanks!

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
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Re: JSP compilation problem

2004-12-31 Thread Frank W. Zammetti

Interesting response... The exact same JSP is compiling on two other 
machines.  Your right though, manually compiling it is a good next step 
(one that I'm ashamed to say I didn't think of myself), so I'm off to do 
that now.  Maybe I have a corrupt file in some minor, hard-to-detect way 
that is causing a problem on this one Tomcat instance.  Thanks for the 
suggestion, it's a logical course of action.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Ryan Stewart wrote:
Quite simply, you have an error in your JSP that is preventing the translated 
servlet from compiling. If you don't know where to look for the compiler 
output, then just go and manually compile the servlet.
-Original Message-
From: Frank W. Zammetti[EMAIL PROTECTED]
To: Tomcat Usertomcat-user@jakarta.apache.org
Date: Thu Dec 30 06:53:31 PST 2004
Subject: JSP compilation problem
[...]
HTTP Status 500 -
type Exception report
message
description The server encountered an internal error () that prevented 
it from fulfilling this request.
exception
org.apache.jasper.JasperException: Unable to compile class for JSP
[...]
root cause
Compile failed; see the compiler error output for details.
[...]
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Re: JSP compilation problem

2005-01-01 Thread Frank W. Zammetti

I did not post twice Ryan.  If two posts appeared, it is the same 
problem with the list processor that we've been seeing for weeks now.

I did post a reply however... I tried your suggestion and manually 
compiled.  I have NO classpath variable in the environment (I thought 
this might have been a classpath issue, and I guess it could still be, 
but I don't see how at this point).  I manually put servlet-api.jar, 
jsp-api.jar and jasper-runtime.jar in /tomcat/common/lib on the 
classpath and compiled, and it compiles cleanly.  So the problem would 
not appear to be a problem with the generated servlet.  Any other ideas?

Thank you!
--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Ryan Stewart wrote:
I answered you yesterday on this. There's generally no reason to post the same 
question two days in a row. Just wait and see if an answer shows up. Your 
problem is (still) that you have one or more errors in your JSP. If you can't 
figure out where the compiler output is, then go and compile the translated 
servlet manually.
-Original Message-
From: Frank W. Zammetti[EMAIL PROTECTED]
To: Tomcat Usertomcat-user@jakarta.apache.org
Date: Thu Dec 30 06:53:31 PST 2004
Subject: JSP compilation problem

Hello.  I'm using Tomcat 5.0.29.  Working from home today and trying to 
run a working application on my laptop, and I'm seeing an exception when 
trying to access the first JSP of the app.  Here's the on-screen display:
[...]
exception
org.apache.jasper.JasperException: Unable to compile class for JSP
[...]
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Re: JSP compilation problem

2005-01-02 Thread Frank W. Zammetti

Very interesting... Switching to JDK 1.4.2 solved the problem.  I didn't 
even do an uninstall/reinstall... I always install my SDK to c:\java, so 
all I did was rename it and copy the directory over from another PC, so 
any paths and registry settings should still be valid, there's just an 
older version in it's place.  I made sure to delete the Tomcat work 
folder for the app, started up Tomcat and tried it, everything worked 
fine... JSP class was generared, servlet compiled, and page came up, no 
problem.

So... Is there actually a problem using JDK 5.0 with Tomcat 5.0.29?  If 
so, what version of Tomcat is OK with 5.0? (assuming any are, which I DO 
assume).  Or is this just some sort of fluke situation?

In any case, my problem is solved, and that was the resolution.
--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Ryan Stewart wrote:
First, I apologize if I came of sounding rude before. As an infrequent visitor 
to this list, I wasn't aware that you are a frequent contributor. I also don't 
seem to have received the other reply you mention. My next thought is that you 
might have two versions of Java installed. If so, which version is Tomcat 
using? Are you sure you compiled the servlet with the same one?
-Original Message-
From: Frank W. Zammetti[EMAIL PROTECTED]
To: Tomcat Users Listtomcat-user@jakarta.apache.org
Date: Sat Jan 01 07:22:09 PST 2005
Subject: Re: JSP compilation problem

I did not post twice Ryan.  If two posts appeared, it is the same 
problem with the list processor that we've been seeing for weeks now.

I did post a reply however... I tried your suggestion and manually 
compiled.  I have NO classpath variable in the environment (I thought 
this might have been a classpath issue, and I guess it could still be, 
but I don't see how at this point).  I manually put servlet-api.jar, 
jsp-api.jar and jasper-runtime.jar in /tomcat/common/lib on the 
classpath and compiled, and it compiles cleanly.  So the problem would 
not appear to be a problem with the generated servlet.  Any other ideas?

Thank you!

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Re: dynamically compile JSPs

2005-01-10 Thread Frank W. Zammetti

Hey, I remember this thread :)
(Mostly because you quoted my comment!)
One solution is to shell out to do the compilation.  I think I 
probably gave it to you last time, but here's the two pertinent lines 
from my compile job that does it:

java -classpath %CP% org.apache.jasper.JspC -v3 -die -d %JSPAppDir% 
-webapp %WebAppDir%

javac -classpath %CP% -d %JspDir% %JspDir%\*.java
...where...
%CP% is the classpath, inclduing servlet.jar
%JSRDir% is the location of the JSP
%WebAppDir% is something like c:\tomcat\webapps\myapp
(I modified this a tad so it's more applicable to you, but don't shoot 
me if you have to hack it slightly)

Now, what I'm thinking, AND I BY NO MEANS ENDORSE THIS AS A GOOD 
SOLUTION, is that you could shell out these two commands, and that I 
think would get the job done.  This is a has a Windows skew to it of 
course, but I can't see any reason it wouldn't work under *nix, if 
that's your environment, which just some minor changes.

I've never tried using JspC from Java code as you did, although I'd 
think that's the way you'd want to go.  I don't know what's wrong with 
the code you provided however, but if you get to that hair-pulling stage 
where you feel like your really stuck, I'm relatively sure the above 
will do it for you, if worse comes to worse.  I guess if this isn't 
something that's going to be happening a lot, it might not be a problem 
this way.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Matt Bathje wrote:
[EMAIL PROTECTED] wrote:
http://jakarta.apache.org/tomcat/tomcat-4.1-doc/jasper/docs/api/index.html 

Usage of the JspC class.  This should be what you want.
I work in Windows 95% of the time, and I'm a simplicity freak, so I 
tend do do things, most of the time, with batch files called from 
UltraEdit.  Anyway, this is relevant because one of the steps in my 
typical build process is a compilation of all JSP's.  I use this class 
to do that.  I can give you the two lines from my batch file that does 
this if it would be helpful, but I tend to think the javadocs will get 
you where you want to go.



This is kind of an old thread I'm replying to - but I implemented what I 
thought would work for this, and haven't been able to get anything 
working reliably. As a refresher, the scenario is this:
- a Tomcat 5.0.x server with Jasper setup in development=false mode
- I upload a jsp page through a web interface, and want it to be 
compiled/usable immediately, instead of waiting for the scheduled jasper 
compilation
- putting ?jsp_compile=true on the page doesn't seem to work
- making development=true isn't an option

After looking through the JspC documentation a little bit, I tried this 
code in my class after the JSP file is uploaded:

JspC antTask = new JspC();
antTask.setArgs(new String[] { uploadTileFilePath });
antTask.execute();
And this does not seem to compile the file reliably. It does seem like 
something is happening, because the upload/compile action takes about 
25-30 seconds longer to load when the jsp compilation code is included. 
In my work directory, the .java and .class files are never updated (new 
time stamp) right away.

Sometimes if I wait a bit (5-10 minutes) the files are updated properly, 
but this seems to be the normal scheduled compilation.

Sometimes if I load the page up in a browser after it has been 
uploaded/compiled, it seems to be compiled on access, but this does 
not always happen.

I was messing around with the code a little bit, and tried this:
JspC antTask = new JspC();
antTask.setArgs(new String[] { -compile, uploadTileFilePath });
antTask.execute();
but this always gave me an error that javax.servlet package could not be 
found.

I then tried:
JspC antTask = new JspC();
antTask.setArgs(new String[] { uploadTileFilePath });
antTask.execute();
antTask.setArgs(new String[] { -compile, uploadTileFilePath });
antTask.execute();
and this seemed to make it (so far) that the JSP page always gets 
compiled the next time it is loaded in a browser.

This is passable if it must be the solution, but what I would really 
like is that the file gets completely compiled during the upload/compile 
action. The reason for this is that I want the person uploading to have 
to deal with the extra processing time, and not the person loading the 
page.

Any help with solving this problem would be greatly appreciated.
Thanks,
Matt
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Re: Long running requests and timeouts?

2005-01-17 Thread Frank W. Zammetti

I can't answer your specific question, but the scenario you describe 
raises a red flag with me in general...

When you potentially have such long-running requests, it's usual a Bad 
Idea(tm) to just allow them to run like this as part of a request.  I 
think it's fair to say that most people would say you should be taking 
some sort of queueing or multithread approach, coupled with polling.

I don't know your usage pattern, but especially if there could be a 
number of such requests coming in at once, you are tieing up server 
resources this way.  You also start running into situations like you 
mention with timeouts (I'm actually surprised the browser itself didn't 
time out after a few minutes).  It also doesn't give a very good 
appearance to the user... it seems like the system has just frozen, 
which it actually hasn't.

If it's feasible, I think you may save yourself some trouble by 
rearchitecting this rather than trying to solve this problem.  You can 
do something as simple as this...

(1) Have a class with two static HashMaps.  One HashMap we'll call 
THREADS and it will store a reference to an object (more on this in a 
second), keyed by userID... In the other that we'll call STATUS you will 
store a Boolean, also keyed by userID.
(2) When one of these long-running requests comes in, spawn a thread to 
handle the XML generation, and put a reference to the thread in that 
THREADS HashMap for the userID your servicing (might want to use 
sessionID instead, it's up to you)... In the STATUS HashMap, store a 
false Boolean (false means the request hasn't completed yet).
(3) Return a Plase Wait page to the user.  Use a simple JavaScript 
timeout to call a status checking function every few seconds that checks 
the value of the Boolean.  If false, just return that Please Wait page 
again.
(4) When the thread completes, it should set that Boolean to true for 
that userID.
(5) When the status checking function finds True, it should (a) get the 
reference to the thread from the THREADS HashMap, (b) get the XML from 
the thread (just store it in a class-level variable and expose it with a 
getter), (b) set some value in the thread object that indicates the 
thread should die, (c) return the XML to the browser.

Does that all make sense?  I don't know if your in a position to 
rearchitect what your doing, but if you are, I very much suggest doing 
so.  Hope this helps!

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Andrzej Jan Taramina wrote:
I have a situation where some requests that get sent to Tomcat are very long 
running (basically batch operations).  I've been testing with a request that 
takes just over 7 minutes to process and returns and XML document as a 
response.

The problem I'm having is that the response gets truncated.  It's always 
truncated at a consistent spot (3207 characters for some reason, that's what 
Firefox reports).

Shorter running requests don't truncate anything, regardless of how long the 
response might be.

I'm running Tomcat 5.0.28 and my Connector in the Tomcat server.xml file 
looks like:

Connector port=80
	maxThreads=150 minSpareThreads=25 maxSpareThreads=75
	enableLookups=false redirectPort=8443 acceptCount=100
	debug=0 connectionTimeout=2 
 	disableUploadTimeout=true /

Is the connectionTimeout value the one that might be contributing to this 
behaviour?

Are there any other timeout settings that might affect this?
Thanks!
Andrzej Jan Taramina
Chaeron Corporation: Enterprise System Solutions
http://www.chaeron.com
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Re: Long running requests and timeouts?

2005-01-17 Thread Frank W. Zammetti

Ok Andrzej, sorry I couldn't be of any real help.  I see what I 
suggested wouldn't apply in your situation, I was just taking a guess 
anyway.  And certainly I understand the pressure of deadlines :)

Perhaps my approach might help someone else that's just lurking, but 
good luck in solving your problem.  I too will be watching to see what 
your solution is, just out of curiosity.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Andrzej Jan Taramina wrote:
Frank:

I don't know your usage pattern, but especially if there could be a 
number of such requests coming in at once, you are tieing up server 
resources this way.  You also start running into situations like you 
mention with timeouts (I'm actually surprised the browser itself didn't 
time out after a few minutes).  It also doesn't give a very good 
appearance to the user... it seems like the system has just frozen, 
which it actually hasn't.

These requests are not going to be called by users through a browser, since 
they are Web Services/REST types of requests.  The only time they might get 
called through a browser is for testing purposes, in which case the tester 
knows that they will be very long running and that's not at issue.

The timeout seems to be affecting scripted invocations of the request as well 
(using the commons-http library), so it doesn't seem to be a browser timeout 
issue as far as I can tell.


If it's feasible, I think you may save yourself some trouble by 
rearchitecting this rather than trying to solve this problem.  You can 
do something as simple as this...

Does that all make sense?  I don't know if your in a position to 
rearchitect what your doing, but if you are, I very much suggest doing 
so.  Hope this helps!

This does make sense, except for the user part, since users will never access 
the URL's involved directly.

Furthermore, these long running tasks will be called by a scheduler, off 
hours, and typically there will be very few such requests a day (maybe 2 or 3 
max).  The requests are really single overnight batch processing runs.

However, deadlines preclude rearchitecting the solution to make it 
asynchronous as you suggest (it's currently synchronous) in the short term.  

Hence my looking for a way to easily fix the timeout issue that causes the 
response to be truncated when Tomcat services a long running request.

Thanks for the inputmost appreciated.
Andrzej Jan Taramina
Chaeron Corporation: Enterprise System Solutions
http://www.chaeron.com



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Re: What is it mean that Java code does not belong in well designed JSP pages?

I certainly wouldn't presume to speak for Craig, so this is just my own 
answer...

Scriplets, that is, code in JSPs inside % %, is generally considered a 
Bad Thing(tm) because it's too easy for business logic to sneak into the 
presentation.

Now, there is I think room for debate about how far to push that idea. 
Some people think that a JSP should be absolutely nothing more than a 
template for display, so you should wind up with nothing but things like 
$=someVar%, or more correctly, something like bean:write 
name=myBean property=myVar /.

However, where there is room for debate is whether using any sort of 
logic whatsoever in a JSP is bad or not.  Taking the JSP as a template 
only idea to it's fullest extent seems to me to imply that logic in ANY 
form is to be avoided, and should not be done in a JSP, whether it's 
using taglibs or not to do it (i.e., logic:equal/ shouldn't even be 
used because it's logic).  I think this is too extreme and limits the 
types of applications you can do... try doing the kinds of apps I do for 
a living for example, which are webapps that look, feel and work like 
fat clients, and you'll be hard-pressed to pull off the kinds of things 
I do without some level of logic in JSPs.

That being said, good design dictates that you need to be careful what 
gets put in your JSPs, whether you use custom tags or not (I'm not a fan 
of custom tags myself in most cases).  Business logic does NOT belong in 
JSPs, and indeed anything other than trivial bits of code probably 
shouldn't be there either.

I'm not entirely sure what the code you posted is doing, but my gut 
feeling is that it's too much for a JSP.  I do things like this all the 
time;

%
  boolean altRow = false;
  String  rowStyle = ;
  for (Iterator it = form.getTOAList().iterator(); it.hasNext(); ) {
if (altRow) {
  rowStyle = cssListboxAltRow;
  altRow = false;
} else {
  rowStyle = ;
  altRow = true;
}
HashMap nextItem = (HashMap)it.next();
BigDecimal toaID = (BigDecimal)nextItem.get(toaID);
String status = (String)nextItem.get(status);
%
tr height=24 class=%=rowStyle%
  td%=status%/td
  td%=toaID%/td
/tr
%
  }
%
...and some will say that's way too much... let's skip the this should 
be a custom tag! argument for the time being... This kind of code I see 
no problem with being in a JSP.  It's strictly presentation-oriented, 
and isn't extensive.

That being said, NOW we can get to the this shouldn't be there at all 
argument... it is a perfectly reasonable argument.  In an environment 
where you have page authors and Java coders, you don't want your page 
authors to have to see code like that.  In fact, in the perfect 
environment where it's split exactly right, they wouldn't even know what 
this code meant.  But, if you had a custom tag that encapsulated that 
functionality, they could just put showTOAList/ and be done with it. 
That's the argument for taglibs (the main one anyway).

However, you have to ask yourself what kind of environment your in... I 
dare say most environments are NOT set up that way... maybe they should 
be, but I don't think the majority are... most places, your page authors 
are your Java coders are your database developers are your business 
analysts, etc.  In that case, I think the argument doesn't carry as much 
weight.

Eh, I guess I'm off on a bit of a tangent.  Most people will tell you 
that code in JSPs is to be avoided, and I'm not going out of my way to 
debate that.  But, I think it's fair to say that if you do have code in 
JSPs, it should be (a) trivial and (b) strictly presentation-related. 
Breaking THOSE rules, which by extension breaks the higher rules, is to 
be avoided at all costs.  Just my opinions.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Dola Woolfe wrote:
I just read this thread and didn't quite understand
it. If it means what it seems to mean on the surface,
I'm doing everything wrong.
Schematically, my typical JSP page looks like the
following (basically 100% code). Is this what Craig is
advising against?
%@ page errorPage=ErrorPage.jsp import=html.*%
[EMAIL PROTECTED] file=InitializePage.jsp%
%
Table table = new Table()
.pAddH(#).pAddH(Action).pLN()
.pAddC(1).pAddL(new Anchor(HelloPage.jsp, Say
hello to my friend.)).pLN()
.pAddC(2).pAddL(new Anchor(GoodByePage.jsp,
Say good bye to my friend)).pLN()
;
MyTemplate template = new MyTemplate (Main
Actions, table);
Page pAgE = new Page(new MyHead(Data Tools), new
Body(template));
%
%= pAgE %
		
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Re: What is it mean that Java code does not belong in well designed JSP pages?

David Johnson wrote:
Using taglibs instead of code adds a level of obfuscation that, IMHO, 
makes it difficult to get work done.  I always end up taking the servlet
that was generated from the JSP and rewriting it so it works correctly,
performs adequately, and generates no side effects.
This has always been my biggest problems with taglibs too, that and the 
fact that it's yet something else a new developer coming on to a project 
has to learn before they can be effective (or at least optimally 
effective).  I prefer all the code being right there in front of me, not 
having to go hunt down source somewhere.

Additionally, I don't like having to recompile a class to make a change 
and then redeploy the class (or worse yet, the whole app).  If it's just 
in a JSP, I can update the app on-the-fly (assuming JSP compilation is 
still active).

That being said, I actually like the idea of Tag Files.  It's not quite 
as bad, it's no worse than a JSP include, although the point about more 
to learn still stands.  But, then it's just usual JSP code, which they 
would already know, so it's still not quite as bad in that regard 
either.  It's kind of amazing that a lot of people don't even know about 
that capability.

Like you said though, what works in one environment may not work in 
another, and taking a hard stand either way is a bad idea.  Heck, I've 
used taglibs on plenty of occasions and it's worked out beautifully. 
Right tool for the job and all that jazz, right?!?

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
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Re: What is it mean that Java code does not belong in well designed JSP pages?

That's a good point Tim... I have to admit I've only used methods a 
couple of times in JSPs, generally preferring all the code be inline 
(except where there would be a lot of duplication, then I tend to make 
utility classes).  You make a good point though, I may start getting 
into that habit myself :)

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Tim Funk wrote:
Essentially you have written a servlet but packaged it as a JSP. Anytime 
it becomes a trivial effort to hand transform a JSP into a servlet 
usually means some refactoring is in order.

Personally I do not mind java code in JSP's but only if its structured. 
I try not to rely on in-line java code - but I try to use methods or 
inner classes for most java coding in a JSP. By doing that - it becomes 
easier to rip the methods and inner classes from the JPS page and into 
an independent object. By doing this - I get rapid turnaround - but 
don't code myself in a hole for when new functionality might be needed 
that might overlap existing pages.

-Tim
Dola Woolfe wrote:
I just read this thread and didn't quite understand
it. If it means what it seems to mean on the surface,
I'm doing everything wrong.
Schematically, my typical JSP page looks like the
following (basically 100% code). Is this what Craig is
advising against?
%@ page errorPage=ErrorPage.jsp import=html.*%
[EMAIL PROTECTED] file=InitializePage.jsp%
%
Table table = new Table()
.pAddH(#).pAddH(Action).pLN()
.pAddC(1).pAddL(new Anchor(HelloPage.jsp, Say
hello to my friend.)).pLN()
.pAddC(2).pAddL(new Anchor(GoodByePage.jsp,
Say good bye to my friend)).pLN()
;
MyTemplate template = new MyTemplate (Main
Actions, table);
Page pAgE = new Page(new MyHead(Data Tools), new
Body(template));
%
%= pAgE %
   
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Re: ?? Sharing the JSTL JARS and Classloading ??

Tony LaPaso wrote:
There's a more important issue at work here than whether or not I have 
to put the JARs in common/lib or shared/lib: When writing code it's 
considered a bad practice (and I think, rightfully so) to copy and 
paste the same code to various locations. Instead, we factor out common 
behavior into separate classes or methods. There's an analogous idea 
involved here --  instead of copying and pasting the same JARs across 
many web applications it makes more sense (to me, anyway), to factor out 
these JARs and make them centrally available. Having said that, I also 
realize the code within the JARs must be written such that the classes 
can be shared.
The flip side of that of course is that you'll potentially run into the 
same problem as Windows: DLL Hell, although it'll be JAR Hell now :)

The point about administrative simplicity is well-taken, but I've always 
been of the mindset that I'd rather have the JARs repeated in each 
webapp because then if I have to change a JAR version for a particular 
app I don't have to go and make sure all the other apps work with that 
version too.

Same problem with DLLs... how many times have you had a version conflict 
with MS Common Controls?  Maybe not recently because some work has been 
done to alleviate this situation, but certainly in the past is arose all 
the time.  The same could happen if you make JARs shared across webapps.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
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RE: persistence after the request response cycle

2004-09-19 Thread Frank W. Zammetti (MLists)

The other common approach is to re-send the data for page 1 as hidden form
fields with the page 2 form submission.  That way, the second time the
servlet is executed, it is getting all the required data as part of
request.

As a general rule (which is broken often for one reason or another!), if
the amount of data is somewhat large (or could be, like a textarea's entry
perhaps), then session tends to be frowned upon because it becomes a
performance concern and a potential problem in a distributed environment. 
But if the size is small, session makes life easier, but be aware that
server resources are being eaten with sessions, therefore if you envision
a rather large client load, it can become an issue (but this tends to be
solvable just by throwing hardware at the problem most of the time).

-- 
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

On Sun, September 19, 2004 6:02 pm, Craig Berry said:
 The usual mechanism for this is to persist intermediate data to a
 session-scope object which is persisted after all data has been
 accumulated.  Struts provides excellent support for this pattern.


 -Original Message-
 From: ian stone [mailto:[EMAIL PROTECTED]
 Sent: Sun 9/19/2004 11:25 AM
 To:   Tomcat Users List
 Cc:
 Subject:  persistence after the request response cycle
 Hi All,

 In my present set up I have a servlet serving a HTML
 page, the HTML page returns the form data via POST
 which the same servlet saves to a MySQL database.

 I'd like to extend the present setup so that after
 receiving the 1st POST data, the servlet responds with
 HTML page 2. HTML page 2 then returns form data via
 POST to the same servlet. The servlet would then save
 the accumulated responses from HTML pages 1  2 to the
 MySQL database.

 How can I get the servlet to remember or persist the
 response of HTML page 1 without writing to the
 database or to file.

 Thanks
 Ian





 ___ALL-NEW Yahoo!
 Messenger - all new features - even more fun!
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Re: Tomcat vs BEA Weblogic?

2004-09-19 Thread Frank W. Zammetti (MLists)

The one comment I would make is that with BEA, you have a certain degree
of accountability that you don't have with an open-source product.  That
can be important in a business environment.

I'm probably starting a religious war by posting this, but to some
companies it is frankly more important to have someone that's on the hook
for problems that arise (and ultimately someone that is legally liable
should it really go bad), and you just don't have that with an open-source
project.  This may or may not be important in your environment, and to be
sure there are plenty of advantages that OSS has over commercial offerings
and you need to weigh those against the downside(s).

I'm not sure I can really comment in terms of how they compare from a
technological standpoint.  I can tell you that WebLogic is a very robust
platform (having previously had some apps running on it), and one benefit
that you might see is that having all the various pieces coming from the
same vendor might make it more stable (think BEA vs. Tomcat w/JBoss and
Axis all pieced together).  This isn't necasserily true, but could be.

On the flip side, all that functionality comes at the price of added
complexity.  Tomcat really is very simple to get going with and to
administer and tune, and if it has all the functionality you need, this
can be a boon to your work.

I do have one app hosted on Tomcat.  It's what I would call a
low-to-mid-size app load-wise (around 75 concurrent users at any given
time, on the order of 5,000 requests per day).  Tomcat gives us fantastic
performance with that load, so my guess it that it will scale quite a bit
further.

The other thing to be careful about, since you said you are inheriting
this app, is if the programmers did anything that is WL-specific that
you'd have to deal with to convert.  If there's nothing, the decision is
in some ways harder because you can justify Tomcat a little bit easier (on
cost if nothing else).  If there's ANYTHING that's WL-specific, if I were
in your shoes, I'd probably stick with WL, just to try and minimize any
problems I might get blamed for.  It might be tough to figure out if
there's anything that might be a problem or not, so possibly it's better
to play it safe.

In short, I'm a big fan of Tomcat, I use it exclusively during development
and use it in production as well, but since you have an existing app
already running on WL, and since it is a business environment, all things
considered, I'd tend towards the side of sticking with WL.  Especially if
your company doesn't have a problem with the price, I think my lean would
increase!

-- 
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

On Sun, September 19, 2004 7:31 pm, Bjørn T Johansen said:
 I am taking over a project that's running on Weblogic 8.1 SP3 today.. They
 are only using
 the jsp-container and it is time to renew the support agreement with BEA.
 So I was just wondering, is it worth it? Or is Tomcat as good as WL or
 maybe better? Does
 WL have features that is missing in Tomcat? When the time comes to use
 EJB, is JBoss as
 good as/better than WL?

 So basically, I would like some advice on why I should/shouldn't continue
 with Weblogic? :)



 Regards,

 BTJ
 --
 ---
 Bjørn T Johansen
 [EMAIL PROTECTED]

 ---
 Someone wrote:
 I understand that if you play a Windows CD backwards you hear strange
 Satanic messages
 To which someone replied:
 It's even worse than that; play it forwards and it installs Windows
 ---

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Re: method level synchronization doesn't work

2004-09-30 Thread Frank W. Zammetti

Why not just let SQL do the update?  Do the following:
update my_table set counter_field = counter_field + 1 (where clause here 
if needed)

(off the top of my head, my syntax might be off)
In other words, why not let the database handle the concurrency issue? 
That's kind of what they're there for (partly anyway).

Malia Noori wrote:
Thank you for replying, but I would appreciate it if you could expand on
your explanation.  Here is my original post:
Actually, the data that I am modifying requires a transaction and
synchronization.  It increments a counter stored in the database.  So, I
have to do a select to get the current value, increment the counter, and
then insert the new value.  So if two threads are accessing it at the same
time, the counter will not be properly incremented.  What's puzzling is
that
method level synchronization does not work while synchronizing on a block
of
code inside a method works. 


Regardless of what persistence mechanism I use (i.e. Hibernate, EJB, etc), I
have to synchronize on the method that increments the counter stored in the
database.  I can't avoid this due to business logic.  Please let me know if
there is alternative to synchronization.   

Thanks,
Malia
-Original Message-
From: QM [mailto:[EMAIL PROTECTED] 
Sent: Thursday, September 30, 2004 3:01 PM
To: Tomcat Users List
Subject: Re: method level synchronization doesn't work

On Thu, Sep 30, 2004 at 01:14:26PM -0400, Malia Noori wrote:
: I thought Tomcat instantiates only 1 instance of JSP servlet to handle all
: requests.  Isn't that the reason why it's not suggested to have instance
: variables?
Close, but not quite. ;)
The servlet spec permits a container to create as many instances of a
servlet class as it sees fit.  The same goes for creating and destroying
a servlet object several times over a context (webapp) lifetime.
That said, a servlet's main methods -- doGet(), doPost(), service() --
may be called concurrently for the same servlet object.  These methods
are thus meant to be thread-safe, and as such they shouldn't modify
object instance variables.  (It's fine to call such variables, as long
as they are read-only or at least treated as such.)
: If it is the case that 2 instance of JSP servlets gets created
: to handle each request, what's the best object to synchronize on?
I missed your original post, so I can say only this: when you find
yourself painted into a corner, it's time to revisit the design stage.
-QM
--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
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Re: method level synchronization doesn't work

2004-09-30 Thread Frank W. Zammetti

Well, I'm not sure it was stated that a return value was needed.  The 
way I read the original post was basically (to paraphrase): I need to 
update a counter field, and the way I intend to do it is to retrieve the 
current value, modify it, and then write it out again as two separate 
queries.  If that's the scenario, I don't see any reason the SQL 
statement I gave (assuming I got the syntax right) wouldn't work just fine.

If your saying that you need to do the update and then retrieve the 
value for some reason, then I agree, it's not as straight-forward.  One 
thing that MIGHT work, although I'd frankly have to go try it myself to 
be sure, is a subquery, something along the lines of:

select (update table set counter=counter+1) as counter from table
Even if the theory is correct, I'm not sure about how 
database-independant it may or may not be.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Mike Curwen wrote:
Ok, since it's been brought forward...
how do you update and retrieve all in one query?  This is for: I need a new
primary key, and I need it to be thread safe.
 
something that would run on mysql?
 
unless you can get this magic query, it's not quite as simple as let the
databse handle it, is it?


-Original Message-
From: Peter Lin [mailto:[EMAIL PROTECTED] 
Sent: Thursday, September 30, 2004 7:42 PM
To: Tomcat Users List; [EMAIL PROTECTED]
Subject: Re: method level synchronization doesn't work

that would be the easiest way.
but you made it too easy, I thought people are suppose to 
suffer and stumble :)

peter
On Thu, 30 Sep 2004 17:46:51 -0400, Frank W. Zammetti 
[EMAIL PROTECTED] wrote:

Why not just let SQL do the update?  Do the following:
update my_table set counter_field = counter_field + 1 (where clause 
here if needed)

(off the top of my head, my syntax might be off)
In other words, why not let the database handle the 
concurrency issue? 

That's kind of what they're there for (partly anyway).
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Re: Reducing network traffic for rollover images

2004-10-02 Thread Frank W. Zammetti

Yep, turns out this is a known issue with IE.  I guess that's the reason 
CSS-based mouseovers aren't used much more often.

You may want to take a different approach here... Consider doing what is 
probably the more common approach, which is to have two versions of your 
menu items, a normal state and a hover state version, and switch them 
via Javascript (using the pre-loading I mentioned).

There does some to be some ways around the CSS problems though having to 
do with layers on top of each other and hiding one or the other.  I 
played for a few minutes to get such an approach to work and I got about 
95% of the way there (still had a problem with the actual content being 
placed properly over the background).

I'd personally just go with the first approach.  Like I said, I think 
it's the more common approach, and even though the CSS approach might be 
more appealing, the other way will probably be more cross-browser (if 
you consider this constant loading of issues in IE, and in Opera and 
some others from what I read, to be a cross-browser concern as I would).

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Robert Hunt wrote:
To clarify:
Watching the Tomcat access log and using permutations of CSS and the
FrankZ/jscript-caching-strategy to achieve the rollover effects, I've found
that the background image is requested:
   IExplore 6.0Netscape 7.2
  -  --
CSSeach mouseover   once per page(1)
JS   once per page(2)  once per page(2)
  each mouseover
(1) upon first hover/mouseover
(2) when the jscript executes

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Re: Reducing network traffic for rollover images

2004-10-02 Thread Frank W. Zammetti

I really think this is a case where we might be trying to hard to be 
innovative... Just do the typical two versions of an image and some 
scripting approach.  Sure, slightly less maintainable, and yes, not 
quite as elegant code-wise, but it's a proven method that works across 
just about any browser (with JS enabled of course, but it degrades 
nicely to just the single normal state image, so no harm there).

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Robert Koberg wrote:
Robert Hunt wrote:
To clarify:
Watching the Tomcat access log and using permutations of CSS and the
FrankZ/jscript-caching-strategy to achieve the rollover effects, I've 
found
that the background image is requested:

   IExplore 6.0Netscape 7.2
  -  --
CSSeach mouseover   once per page(1)
JS   once per page(2)  once per page(2)
  each mouseover
(1) upon first hover/mouseover
(2) when the jscript executes

I have been hoping someone would offer some innovative solution, but 
there really isn't one...

You have to perform some ugly hack. Check http://alistapart.com for some 
solutions.

For example, you could provide the image with both (3?) states and 
adjust the margin to show the correct state:

a
  href=boo
  class=hoverLink normal
  onmouseover=this.className='hoverLink hover'
  onmouseout=this.className='hoverLink normal'boo/a
With the image looking like:
-
|  normal state | 30px in ht
-
|  hover state  | 30px in ht
-
.hoverLink {
background: url(images/states.gif);
}
.normal {
margin-top: 0px;
}
.hover {
margin-top: -30px;
}
something like that... :(
best,
-Rob
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Re: Reducing network traffic for rollover images

2004-10-03 Thread Frank W. Zammetti

I agree, and I actually had typed up almost an identical message but 
then decided not to send it (for some reason that I don't really recall).

I do think the CSS-only approach is a nobel goal and is moving in the 
right direction.  A fairly big problem with using CSS nowadays though is 
browser adherance to standards (read: IE!).  It's not too bad if you 
stick with CSS1, but anything above that tends to become an issue, and 
of course it is what's above CSS1 that is of interest for the most part :)

But yes, I agree completely with Nikola, and that's why I said (and I'm 
pretty sure I did send this message) that we might be trying to get too 
clever with the CSS-only approach.  Going with Javascript and images is 
slightly less convenient to maintain, but it will likely be more 
cross-browser, and will degrade nicely in browser with scripting is 
diabled (you'd only see the usual non-hover state of the image all the 
time).

Speaking of maintenance convenience... I don't like to plug products, 
but I've come to really like Xara WebStyle for buttons and things like 
this.  It makes changes very easy.  I have a rather complex application 
I built at work, and one of the requirements was a TON of tabbed dialog 
screens (the sheets were all dHTML-based, and the tabs were 
image-based because that was the way to achieve the look-and-feel they 
wanted).  Anyway, we're talking about something in the neighborhood of 
400 or so tab images because there was around 100 unique tabs throughout 
the system and each tab has four different versions (normal, hover, 
disabled and highlighted).  WebStyle makes it incredibly easy to create 
the images in a wizard-like way, so when someone needs a new tab or 
slightly different verbiage, no problem, only takes a second to generate 
the image.  For interface element graphics that you think might change 
with any kind of frequency (and to me this means AT ALL!), a program 
like WebStyle can be your best friend.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Nikola Milutinovic wrote:
Robert Hunt wrote:
After some analysis and trial  error, I've found** that the correct 
JS syntax in this application is:

   {HTMLElement}.style.backgroundImage  =  'url( ' + img1.src + ')';
where {HTMLElement} would be this as in:
   a href=xxx onmouseover=this.style.backgroundImage = 'url(' 
+ img1.src + ')'; ...

Why are you using background? Why not a regular image?
a href=... onMouseOver=img1.src = 'img1_over.gif' 
onMouseOut=img1.src = 'img1.gif'
img name=img1 id=img1 src=img1.gif
/a

Or you can use DOM style: onMouseOver=document.getEllementByID( img1 
).src = 'img1_over.gif'

Watching the Tomcat access log and using permutations of CSS and the 
FrankZ/jscript-caching-strategy to achieve the rollover effects, I've 
found that the background image is requested:

   IExplore 6.0Netscape 7.2
CSSeach mouseover   once per page
JS   each mouseover   once per page

Try the real image, that is pre-fetched in a script.
So, as has been 99% of my experience, NS does it right, IE leaves a 
bit to be desired.  heavy sigh  It appears that when 
.style.backgroundImage is modified in IE, another HTTP GET request 
is triggered.  I'm going to see if I can do a swap with a hidden 
element that (already) has the desired style and see if I can fake out 
IE.

I understand what you want to do. You want your rollover to be done in 
CSS, no JScript or JavaScript involved. I'm afraid ther is no ellegant 
way of doing it. Using the background is awkward. That a ellement has 
to wrap something other than thin air. So you'll be placing a 
transparent GIF or something else traslucent inside the tag.

No, image rollovers work best the traditional way.
Nix.
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Re: JSP under /WEB-INF folder

Just from a curiosity standpoint Jack... I've already decided it's not 
an approach I'd advocate, but I am interested to know how you serve 
things like graphics and stylesheets from under WEB-INF.  I assume all 
your graphics are actually server by an Action (a trick I've pulled when 
serving images from a database), and I further assume your stylesheets 
aren't just linked in...

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Dakota Jack wrote:
snip
On Tue, 28 Dec 2004 13:57:33 -0500, Frank W. Zammetti
[EMAIL PROTECTED] wrote:
I think his problem is probably linking to stylesheets and such...
Actually, now I have to ask you... if you put *everything* under
WEB-INF, I assume you are serving all graphics from a fronting web
server then?  Otherwise, any document returned to the user that links
back to a resource under WEB-INF won't be reachable, which was the crux
of his problem as I understood it, that's why he was talking about
includes and such all over the place.  But, if you really are serving
everything from there, how are you doing it?  Just curious at this point :)
--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Dakota Jack wrote:
I don't know why you are saying that css and/or js must be placed
directly under WebRoot.  Why do you?  I can give you various
solutions, once I find out what the problem is supposed to be.  There
is no issue, by the way, with putting your JSP files under WEB-INF.
There are other ways to protect access, but this is, I think, a good
one too.
Jack
/snip
Frank, are you still interested in this?  I just noticed it.
Jack


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Re: JSP under /WEB-INF folder

One thing worth pointing out about this is that you'll lose the benefit 
of fronting your app server with a web server... You won't be able to 
offload the serving of images, stylesheets and such, from the app server 
to the web server.  That's probably not a big problem in many cases 
where a single server with a decent set of specs can handle the load 
anyway, but in a more robust enterprise environment, your really kind 
of defeating the purpose of a fleet of web servers in front of a number 
of app servers.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Dakota Jack wrote:
snip
On Sat, 29 Jan 2005 09:00:39 -0500, Frank W. Zammetti
[EMAIL PROTECTED] wrote:
Just from a curiosity standpoint Jack... I've already decided it's not
an approach I'd advocate, but I am interested to know how you serve
things like graphics and stylesheets from under WEB-INF.  I assume all
your graphics are actually server by an Action (a trick I've pulled when
serving images from a database), and I further assume your stylesheets
aren't just linked in...
/snip
img src='resource.do?file=whatever.jpg'
link
href='resource.do?file=whatever.css'
rel='stylesheet'
type='text/css'
You can also put this sort of Struts protocol into Flash ActionScript, etc.
To be complete on this list:
public final class ResourceAction
extends Action {
  public ActionForward execute(ActionMapping mapping,
   ActionForm form,
   HttpServletRequest request,
   HttpServletResponse response)
  throws IOException,
 ServletException {
String file = request.getParameter(file);
String ext  = file.substring(file.lastIndexOf('.') + 1);
String type = null;
String path = null;
if (gif.equals(ext)) {
  type = image/gif;
  path = path(gif);
} else if (jpg.equals(ext)) {
  type = image/jpeg;
  path = path(jpeg);
} else if (css.equals(ext)) {
  type = text/css;
  path = path(css);
} else if (flash.equals(ext)) {
  type = application/x-shockwave-flash;
  path = path(flash);
} else if (text.equals(ext)) {
  type = text/plain;
  path = path(text);
} else if (js.equals(ext)) {
  type = text/javascript;
  path = path(js);
} else if (png.equals(ext)) {
  type = image/png;
  path = path(png);
} else if (html.equals(ext)) {
  type = text/html;
  path = path(html);
} else if (applet.equals(ext)) {
  type = application/x-java-applet;
  path = classes + File.separator + com + File.separator +
crackwillow + File.separator + applet;
}
String name = Classpath.WEB_INF + path + file;
response.setContentType(type);
response.setHeader(Cache-Control, );
response.setHeader(Pragma, );
response.setHeader(Expires, );
response.addHeader(Content-Disposition,filename= + name);
try {
  FileInputStream fis   = new FileInputStream(name);
  BufferedInputStream bis   = new BufferedInputStream(fis);
  byte[]  bytes = new byte[bis.available()];
  OutputStreamos= response.getOutputStream();
  bis.read(bytes);
  os.write(bytes);
  os.flush();
  os.close();
} catch (IOException ioe) {
  StdOut.log(SiteConstant.ERROR_LOG,ResourceAction: problem file
is:  + name + \n + StackTrace.trace(ioe) + \n +
ioe.getMessage());
}
return null;
  }
  private String path(String fileType) {
return resource + File.separator + content_type +
File.separator + fileType + File.separator;
  }
} ///;-)



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Re: JSP under /WEB-INF folder

 Lo, Frank.  You really don't lose anything.  You just gain a choice.
 There is a lot more to be said on this, but you probably would know
 everything on this anyway, so I will leave it at that.
That's not strictly true though Jack (neither your premise that you 
don't lose anything or that I know everything about this, I almost 
certainly don't!)...

In some environments, as I'm sure you know and probably have even dealt 
with, you have a bunch of web servers in front of a bunch of app 
servers.  The web servers serve static content like images, stylesheets 
and usually server-side includes, things like that, while the app server 
handles JSPs and actual server-side (servlet) code.

Putting everything under WEB-INF removes this choice because every 
request has to be routed to your app servers now.  In larger scenarios, 
the whole point of the web servers (well, most of the point anyway) is 
to offload that work from the app servers and gain efficiency.  Division 
of labor and all that jazz. :)

I'd certainly agree that if a particular situation doesn't call for such 
a distributed environment in the first place, than it's a moot point, 
and what you suggest certainly has some benefits.  But if that's not the 
case, or if it some day might not be the case (i.e., your app might have 
to scale into such an environment), then it could become an issue and 
people should be aware of it before they make their decision.

I also don't know what effect this might have in a true distributed 
environment (i.e., might it be a problem if one request, say for an 
image, is serviced by one machine, while another services the JSP 
execuetion itself?).  This might never arise, or it might not be a 
problem at all even if it does, but it could be something for someone to 
explore is my point.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Dakota Jack wrote:
snip
On Sat, 29 Jan 2005 17:17:03 -0500, Frank W. Zammetti
[EMAIL PROTECTED] wrote:
One thing worth pointing out about this is that you'll lose the benefit
of fronting your app server with a web server... You won't be able to
offload the serving of images, stylesheets and such, from the app server
to the web server.  That's probably not a big problem in many cases
where a single server with a decent set of specs can handle the load
anyway, but in a more robust enterprise environment, your really kind
of defeating the purpose of a fleet of web servers in front of a number
of app servers.
/snip
Lo, Frank.  You really don't lose anything.  You just gain a choice. 
There is a lot more to be said on this, but you probably would know
everything on this anyway, so I will leave it at that.

Jack


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Re: JSP under /WEB-INF folder PROTOCOL PAGES (ProtocolPages)

 in a distributed environment.  I'd be interested to hear your 
thoughts on this point...

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
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[OT] Re: JSP under /WEB-INF folder PROTOCOL PAGES (ProtocolPages)

.
Not following... reading from where?
Well, I bet you are being too humble.  I am happy to say that my wife
just thinks I am the most adorable, wonderful, guy. Go figure, eh?
That's what I like, woman that are easy to please :) (You were left SO 
wide open there I just couldn't resist!)

  Technology seems to get ahead of rumor in our little world of web
work.  So, I definitely would like to revisit this.  I am going to
squeeze getting the *facts* in here soon.
I look forward to your test results :)
This seems to be false to me.  Maybe I misunderstand you.  I don't
think the browser has a clue whether we are looking at src='myCss.css'
or src='resource.do?file=myCss.css'.   Right?
Jack
That's right, the browser doesn't know the difference, but the server 
side does, and I put that in quotes because it's a little tricker in 
this discussion to define it.

Here's a typical sequence chart, simplified a bit:
* Browser requests page from web server-
* Web server returns HTML page-
* Browser parses page and constructs list of resources to retrieve...
* Each image is requested from web server (in parallel, one hopes!)-
* Web server returns images, in many cases from a memory cache-
* Browser renders page.
Nothing unusual there.  So you have 11 total round-trips to the 
server, one for the document, 10 for the images...  It might be the 
same HTTP connection, but that's not definite (in fact I think it's 
definitely NOT the case, HTTP being stateless and all, but there could 
be something I don't know there at a very low level), and ultimately not 
relevant to this discussion anyway because it's still 11 requests, 
whether the actual connection is torn down between them and rebuilt anew 
for each or not.

Now, let's see what happens using ResourceAction, and I'll take the 
simpler case of the page being straight HTML and not a JSP...

* Browser requests page from web server...
* Web server returns HTML page-
* Browser parses page and constructs list of resources to retrieve...
* Each image is requested from web server-
* Web server recognizes .do and passes the request on to app server-
* App server performs whatever functions it needs to in order to fulfill 
the request (in this case we're talking the whole litany of Struts 
functionality, including your Action of course)-
* (Does the app server pass the response back to the web server to 
serve, or does it serve it directly to the client at that point?  I'm 
actually not sure, but let's be optimistic and say the web server is out 
of the equation at this point, although I suspect that's NOT the case) 
In any case, images are returned to client-
* Browser renders page.

There is clearly more work done with the second chart because the app 
server is now involved.  How costly is all that work?

You could make the argument that because any servlet-based application 
is incurring those costs with most requests, what's the big deal about 
adding a few more?  To a degree that would be a reasonable argument, but 
scalability is most certainly at risk because viewed from the point of 
view of the app server, a single page really corresponds to 10 app 
server requests.

Even if it's all done in the most efficient way, those ten requests 
look, for all intents and purposes, like 10 simultaneous USERS (assuming 
1 request per user).  So, maybe your app server can handle 100 
concurrent requests... If the web server was allowed to serve the 
images, your app server still has 100 slots available to service 
requests, which corresponds generally to 100 concurrent users... If it's 
serving 10 images for each physical user though, now you can only 
service 10 concurrent users, so you've reduced your overall server 
capacity (as viewed by outside clients) by 90%.  Ouch.

I fully acknowledge those are rough, worst-case numbers... I certainly 
don't mean to imply that your approach is 90% worse.  Not at all!  Just 
trying to illustrate the problem, as I see it, in certain environments.

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Omnytex Technologies
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Re: [OT] Re: JSP under /WEB-INF folder PROTOCOL PAGES (ProtocolPages)

-INF *or* a database, transparently 
to the user and front-end.  That's a nice bit of flexibility to be sure.

I don't say you are mistaken.  I just think that this is going to be
an interesting little inquiry, if you want to chase it to its end,
which is my normal proclivity.
At this point I don't think either of us could walk away with an actual 
answer :)

I understand. All your comments are quite fair, in my opinion.  We'll
look around and learn a bit here.
I leave the leg-work to you :)
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Re: [OT] Re: JSP under /WEB-INF folder PROTOCOL PAGES (ProtocolPages)

Dakota Jack wrote:
app server = (AS) 
struts server = (SS)
req = request
-- = pass
res = response
You lost me here already... What's the difference between the app server 
and the struts server?  Isn't Struts running IN your app server?

With ResourceAction
___
First case HTML = req (AS) res (AS) = 2
Second image JPEG (say) = req (AS) -- res (SS) = 3
.
Tenth image JPEG (say) = req (AS) -- res (SS) = 3
WIthout ResourceAction
___
First case HTML = req (AS) res (AS) = 2
First image JPEG (say) = req (AS) res (AS) = 2
Second image JPEG (say) = req (AS) res (AS) = 2
.
Tenth image JPEG (say) = req (AS) res (AS) = 2
This is 22 versus 32.  Apparently you forgot (I think?) that the app
server has to handle ten images too.  They don't just go out with the
page, although we are looking at this in a very oversimplified sense.
I don't see how you got 22 OR 32! :)  The first request from the client 
is for the HTML document, right?  So that's one request.  The browser 
then sees ten img tags, regardless of what they point to.  So for each 
one it makes a request.  That's 10 requests, right?  So it's 11 in all 
from the client to the server (ignoring for the moment whether 
server means app server alone or web server in front of app server, or 
whatever other configuration you might dream up).

The only different between the two approaches we've been discussing is 
what on the server is going to handle each of those 11 requests... Is 
it a web server sending back a static HTML page for the first request, 
and then an image for each of the subsequent 10 image requests, or is it 
a web server returning the HTML page and then an app server returning 
the images, or an app server returning the page AND the images?

There is no question that the AS is quicker with HTML than the SS, but
I am not so sure about the images.  The SS may be faster.  There is
lots of room here for tuning.
Let me ask you this question... If you are accessing a web site, and you 
connect directly to the Internet, is that, ignoring things like 
caching and such, generally going to be faster than going through a 
proxy?  I'd hope you would say yes.  Now, clearly, if the proxy is doing 
caching and/or other optimizations, it might turn out to be faster, but 
that further proves my point: the web server is like the proxy in this 
example.

--
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Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
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Re: [OT] Re: JSP under /WEB-INF folder PROTOCOL PAGES (ProtocolPages)

Dakota Jack wrote:
I am certain on this one, because you can do this sort of thing
*without* the web or app servers at all.  I do this fairly frequently
with code not unlike and heavily borrowing in principle from Jason
Hunters HttpMessage and HttpsMessage in COS.  The ResourceAction sends
the response and ends the whole process by returning null.
I agree, obviously you can take Tomcat for instance and use it to serve 
everything... I have a production app that is a single server running 
Tomcat and Oracle and that's it, no web server anywhere, everything is 
served from Tomcat whether it's a JSP, an image, an HTML document or 
whatever else.

The question that's in my mind though is what happens when you have a 
web server in front of Tomcat?  Just rendering to the response in a 
servlet might not be enough in that case... Think of a proxy analogy... 
Does the web server almost appear like a proxy?  In other words, a 
request comes in to the web server, does it (a) pass the connection to 
the app server to fulfill, at which point it's done and can service more 
requests, or (b) does it ask the app server for the resource, whatever 
it is, wait for the response from the app server and send it along to 
the client when the app server is done responding?  Same idea as a 
network proxy.

The point being, just because the app server CAN serve everything, 
doesn't necasserily mean it WILL with a web server in front.

But again, I don't know the answer here, it's just a question in my mind.
ceteris paribus
/snip
Heh, I meant to tell you last time, this is Latin, not Greek.  LOL   ///;-)
Really??  Well, I have something to yell at my Macroeconomics professor 
for then!  I know for sure she said it was Greek! :)

Funny aside... My Macroeconomics professor... her last name, and I 
couldn't have made this up, is Economopolous.  That just rules!

But now your pushing those caching decisions back on the browser, right?
 I thought one of your basic premises was to not trust the browser to
construct URLs and such?  Wouldn't you have the same distrust for
caching? (and probably worse since that is at least at the users'
discrection)
/snip
The answers are no, yes, no.  Setting caching in the response object
is not equivalent to setting caching in the meta tags.  This is why
the ResourceAction has an edge.  Note also that the setting of cache,
pragma and expires are runtime alterable, and can override the meta
tags, in ResourceAction.  I left those decisions out of the code I
sent you.  Did you notice where I added in it response to someone's
query on that?
I did notice, but my point is that the browser settings would override 
any tags or headers you set.  I might be wrong about that, but that 
would be my expectation.  After all, what good is a setting in my 
browser that says don't cache anything if a web site designer can come 
along and overrule that?  Surely the FOSS community would be up in arms 
over their loss of freedom, right?!? ;)

--
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Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
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Re: [OT] Re: JSP under /WEB-INF folder PROTOCOL PAGES (ProtocolPages)

I still don't understanding the 32 and 22... What do the [2] and [3]'s 
represent?

Dakota Jack wrote:
Too late when I sent this.  Let me make the necessary alterations to
the nomenclature.  Sorry!
web server = df. (WS)
app server = df. (AS)
request= df. req
response   = df. res
  = df. passing the control
With ResourceAction
1.0  WS req WS res HTML  [2]
1.1  WS req  AS res [3]
1.2  WS req  AS res [3]
1.3  WS req  AS res [3]
1.4  WS req  AS res [3]
1.5  WS req  AS res [3]
1.6  WS req  AS res [3]
1.7  WS req  AS res [3]
1.8  WS req  AS res [3]
1.9  WS req  AS res [3]
1.10 WS req  AS res [3]
 Total 32
Without ResourceAction
1.0  WS req WS res HTML  [2]
1.1  WS req AS res [2]
1.2  WS req AS res [2]
1.3  WS req AS res [2]
1.4  WS req AS res [2]
1.5  WS req AS res [2]
1.6  WS req AS res [2]
1.7  WS req AS res [2]
1.8  WS req AS res [2]
1.9  WS req AS res [2]
1.10 WS req AS res [2]
 Total 22
However, let me note, once again, that we can make it 22 to 22 by
simply sending the attributes that are relevant back to a different
server.  For example, we could have
  img src='http://blahblahblah.com/ResourceAction.do?file=whatever.gif'
Doing this, if we are talking about serving images to a large-scale
site, we could get rid of both the WS and the AS and use a SCS (small
custom server) optimized for this situation.  I do this sort of thing
constantly, *sub rosa*, on my sites.  This is probably quicker than
using WS to serve the images, and certainly so if the images are in
any way dynamic in nature and if we make use of the multithreading
opportunities that crop up in this situation.  But, this is going
afield.  And, this is only looking at the upside too.
Jack

If we are talking about dynamically-created resources, then I would tend 
to agree with your view.  But we have, at least as far as I was 
concerned, been talking about strictly static resources.

In that case, your basic premise boils down to, as I see it:
An app server running ResourceAction can serve resources more 
efficiently than a web server.

Again, strictly talking about static resources, I would be absolutely 
SCHOCKED to learn this is the case under most circumstances.  That would 
be like saying a Cadillac could beat a NASCAR vehicle in 1 ten-lap 
race... It might be able to under some circumstances, like the NASCAR 
driver being drunk!, and certainly there are some very nice trade-offs 
to driving the Caddy like more room and a better stereo, but in general 
you wouldn't expect the Caddy to lose.

A bit of hyperbole there, but the underlying point is what's important.
--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
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Re: [OT] Re: JSP under /WEB-INF folder PROTOCOL PAGES (ProtocolPages)

Dakota Jack wrote:
The good is that the web site designer knows when a change has been
made and the assumption is that you are going to see what the web site
designer has to offer.  No?
Jack
I concur with the assumption, but I don't see it making any 
difference... Remember that what we affectionately refer to as the web 
these days is really a lot more than what it was originally.  One of the 
things that was originally intended is that the client is in complete 
control.  If the user wants to request a resource from a server, and 
they tell their browser via a setting that no, I WANT you to go ask 
that server EVERY SINGLE TIME for the resources, NEVER use what you 
might have in the local cache, then they should be allowed to do that, 
and whatever the web site creator wants you to do is irrelevant.  Same 
idea when the user can override fonts and colors and the like with their 
own local settings.

Nowadays though, us web app/site designers think WE know how best a 
client should view our site, and we actually go out of our way to make 
it so... how many times have you visited a site where the font is too 
small and the usual font size adjustments don't make any difference?  So 
you have to go in to setting and uncheck that User Font Sizes Specified 
By Site option.  Annoying, and not what was originally intended.

This is of course all only relevant to the extent that it supports my 
point, that anything you do on the server side to try and control 
caching is either (a) useless because the end user can override it 
anyway or (b) not in keeping with the spirit of the web, at least, not 
as originally intended.

Now I'm off on a bit of a tangent though :)
--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
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Tomcat control from Ant

2005-02-17 Thread Frank W. Zammetti

Hello all.  I have an Ant build script for an application that stops
Tomcat if it's running, deletes the work folder for the application (so I
can ensure all JSPs get recompiled) and starts Tomcat again.  Here's the
two relevant tasks:


target name=tomcat_cleanup
  delete dir=${app_base_dir}/../../work/Catalina/localhost/toa /
/target

target name=start_tomcat
  exec executable=${catalina_home}/bin/startup.bat os=Windows XP
spawn=true
env key=CATALINA_HOME value=${catalina_home} /
  /exec
/target


app_base_dir is properly defined (I know because the work folder DOES get
deleted) pointing to the root of the webapp, as is cataline_home (because
Tomcat DOES start up).  Here's the problem... When I access the first page
on my application (index.jsp in the root of the webapp), I get the
following:


The file or path you specified (..\..\..\\bin\bootstrap.jar) is invalid
relative to C:\tomcat
org.apache.tools.ant.util.FileUtils.resolveFile(FileUtils.java:761)
org.apache.tools.ant.Project.resolveFile(Project.java:1293)
snip - I'm beting the whole stack trace isn't important


Anyone have any ideas?  Funny thing is, if I manually run startup.bat,
sure enough everything works perfectly as it should.  I don't get it. 
Thanks all!

-- 
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

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Re: Tomcat control from Ant

2005-02-17 Thread Frank W. Zammetti

I figured it out... kinda of obvious after the fact actually...

My catalina_home Ant property was defined as ../../../

You see, all the paths in the build script are defined relative to the
build file, which is always in the directory source in the root of the
webapp.  Everything else works this way, but not catalina_home.

I defined it as c:\tomcat instead and everything works again.  It would be
nice if I could define in relatively like all the rest, so if anyone has
any ideas, I'm all ears.  But, failing that, I can live with this one
absolute path in the build script.

Sorry for the list noise :)

-- 
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

On Thu, February 17, 2005 11:02 am, Frank W. Zammetti said:
 Hello all.  I have an Ant build script for an application that stops
 Tomcat if it's running, deletes the work folder for the application (so I
 can ensure all JSPs get recompiled) and starts Tomcat again.  Here's the
 two relevant tasks:


 target name=tomcat_cleanup
   delete dir=${app_base_dir}/../../work/Catalina/localhost/toa /
 /target

 target name=start_tomcat
   exec executable=${catalina_home}/bin/startup.bat os=Windows XP
 spawn=true
 env key=CATALINA_HOME value=${catalina_home} /
   /exec
 /target


 app_base_dir is properly defined (I know because the work folder DOES get
 deleted) pointing to the root of the webapp, as is cataline_home (because
 Tomcat DOES start up).  Here's the problem... When I access the first page
 on my application (index.jsp in the root of the webapp), I get the
 following:


 The file or path you specified (..\..\..\\bin\bootstrap.jar) is invalid
 relative to C:\tomcat
   org.apache.tools.ant.util.FileUtils.resolveFile(FileUtils.java:761)
   org.apache.tools.ant.Project.resolveFile(Project.java:1293)
 snip - I'm beting the whole stack trace isn't important


 Anyone have any ideas?  Funny thing is, if I manually run startup.bat,
 sure enough everything works perfectly as it should.  I don't get it.
 Thanks all!

 --
 Frank W. Zammetti
 Founder and Chief Software Architect
 Omnytex Technologies
 http://www.omnytex.com

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Re: JavaMail API ?

2005-03-01 Thread Frank W. Zammetti

I wouldn't have expected to see them in Tomcat frankly... Although 
sending eMails from a webapp is relatively common, it's not common 
enough to be included with an app server (well, except for Websphere, 
which generally includes everything under the sun!)

I am kind of surprised it hasn't been incorporated into JDK1.5 though, 
that would have been a reasonable expectation.  Is it perhaps rolled 
into J2EE instead?  I don't know.  Same for JAF.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
David Smith wrote:
No mistake that I know about.  JAF and JavaMail are both separate 
downloads from Sun's site and have been all along.  Licensing issues 
probably prevent them from being included in the Tomcat dist.

--David
Nikola Milutinovic wrote:
Nikola Milutinovic wrote:
Hi all.
I'm running Tomcat 5.5.7 on Windows XP and Sun JDK 1.5.0_01 I notice 
that JavaMail API is missing from BOTH Tomcat and JRE. There is no 
javax.mail.* hierarchy in ${JAVA_HOME}/lib/rt.jar


It is also missing JAF (Java Activation Framework).
I mean, no problem, I CAN get a hold of those JARs, but really, what's 
the story? A simple mistake on Sun's or TC team's part?

Nix.
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.


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Re: Accessing the context path within a Servlet/JSP

2005-04-04 Thread Frank W. Zammetti

See HttpServletRequest.getContextPath()
J Malcolm wrote:
I have looked at the JavaDocs, but I can't find a method that will give me
the context path for a web app:
(i.e. Context path=/abcxyz docBase=...)  All I want is the /abcxyz
string precisely as defined in the context tag.
I have tried getPath() from the servletContext, but it returns part of the
host name as well.  That doesn't make sense either, but that's the way it's
working for me... It returns jndi: for the protocol (???) Am I doing
something else wrong here?
I found the getServletContextName() method.  But that is an optional
parameter on the context tag, and I can't risk using something that might
not be defined.
I'm currently parsing up the URL object returned from
servletContext.getResource(/);  But this is a hack.  Surely there is a
better way to get the root URL context for a web app... (?)
Suggestions??  (BTW... Tomcat 5.5.7)
Thanks.
Jerry

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--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
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[OT] Re: development environment

2005-04-22 Thread Frank W. Zammetti

* Pentium IV 2.8GHz, 2G RAM, dual 21 monitors (CRT's... they're still 
far better to me, screw size!)

* Windows XP Professional as main OS and Redhat8/WinNT/Win98/Mandrake in 
VMWare for testing

* UltraEdit  Directory Opus - This is essentially my development 
environment, these two are where I spend 90% of my time during the day

* Tomcat locally for all development as well as an instance on the 
Redhat VM, a secondary PC next to me (lesser hardware specs, but still 
decent) running Windows 2000 has WebSphere 5.1 which is our production 
app server of choice

* Maxthon and Firefox for testing
* Oracle 9i for all database development
* SourceSafe for some things, CVS for others (we are moving to all CVS, 
but SS is still in use right now)

That's the important stuff I figure.  That's at work by the way, but I 
have an almost identical setup in my home office (laptop instead of 
secondary PC is the big difference), configured in a very similar way, 
so with the full VPN access to work, I can work almost as effectively at 
home as at work, not to mention work on my own stuff off-hours.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Patrick Lacson wrote:
hi All,
I'm curious to what everyone's dev environment looks like.  Here's mine:
hardware
Penium IV 2.0Ghz / 1GB Ram
OS
Windows XP Pro
IDE / Tools
Eclipse 3.x / Emacs

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Re: Nervous about Sessions ...

There *technically* isn't any requirement that things you store in 
session be serializable.  However, since some app servers use databases 
or file systems to persist session information, and that many times is 
implemented using serialization, and since serializable is usually (if 
not always) necessary in a clustered environment to replicate the 
session between nodes, you probably do for all intents and purposes only 
want to store serializable objects in session, just to future-proof 
your app.

Yes, you can store simple java types, and no, you do not *have* to use 
beans (although I think this is generally considered a best practice in 
most cases).  If you do use beans though, you will probably want to make 
sure you only use serializable types in the bean, or mark them transient 
as Viorel mentioned, as per the point made in the first paragraph above.

But again, there's nothing that says you have to do any of this... if 
you KNOW you are only going to run on a single server and if you KNOW 
your app server is only storing session in memory, there is nothing that 
says any object you put in session, on it's own or by virtue of members 
it contains, must be serializable.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
David Whitehurst wrote:
If I use the session to store things, 1. Can I use simple java types? 
2. Do I have to use Java Beans (extends serializable)?

David Whitehurst
Viorel Dragomir wrote:
Yes.
But you can set some attributes of the objects as [ transient ] to not 
be serialized. So you don't have to make all objects in the package 
serializable.


Viorel Dragomir
.
..
---

- Original Message - From: David Whitehurst To: 
tomcat-user@jakarta.apache.org Sent: Wednesday, April 27, 2005 11:31
Subject: Nervous about Sessions ...

Long ago a multi-client, multi-Oracle application was written using 
Struts.  Recently, we had a 4 in 22,000 record data integrity issue.  
I found one client implementation that used prepared statements but 
the primary key was being used e.g. update mytable set a= ?, b=? 
where pri_key =  + pkey +  ' ; ...whoa! I said, called the 
developer and we had a talk.

Then, I also found that where we use a HashMap object it is not 
synchronized.  I suspect that was the data problem, i.e. two records 
saved by two different people, and the data was the same for the 
different records in the same Oracle second.

I'm looking for comments about the use of this HashMap on requests 
but I'm also nervous now where I use Strings in the session e.g. a 
clientname, username, etc. My concern started when I read the posts 
about the non-serializable objects in the session.  Do all java 
objects placed in the session have to be serializable?
Thanks,

David L. Whitehurst
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Re: set header in all responses

A filter is an ideal solution for this... It has the benefit of being 
app-specific, so should you ever want to host another app in the same TC 
instance that doesn't require those headers, they won't be set 
automatically (i.e., at the server-level).

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Rodrigo Avila wrote:
Hi all!
Is possible to put this headers in all responses generated by Tomcat?
response.setHeader(Pragma,no-cache); response.setHeader
(Cache-Control,no-history);
response.setDateHeader(Expires,-1); 

Thanks the attetion.
 


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Re: set header in all responses

Filters:
http://java.sun.com/products/servlet/Filters.html
--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Rodrigo Avila wrote:
right... I need to all apps in an TC instance use these headers... how
I do it? I don't know how use filters / valves...
Thanks!




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Re: RES: Nervous about Sessions ...

Hi Paul,
No, I don't know of any changes... I'm actually wondering if this is a 
restriction the latest servlet spec places on objects in session... I 
tend to doubt Tomcat would be imposing such a restriction unless the 
spec indicated such a restriction... I myself might learn something 
here! :)  Does anyone reading this know a definitive answer?

Frank
Paulo Alvim wrote:
Hi Frank,
I think this post is related to mine:
We had a few non-serializable objects stored in session in TC 5.0.28 but
after migrating the app TC 5.5.9 is throwing
java.lang.IllegalArgumentException: setAttribute: Non-serializable
attribute.
...when we try to put a non-serializable in the session. We are using a JSTL
recommended form like:
(...)
javax.servlet.jsp.jstl.fmt.LocalizationContext lc =
   new javax.servlet.jsp.jstl.fmt.LocalizationContext(bundle);
   javax.servlet.jsp.jstl.core.Config.set(session,
javax.servlet.jsp.jstl.core.Config.FMT_LOCALIZATION_CONTEXT,lc);
(...)
Do you know about any changes related to that in TC 5.5.x?
Thank you!
Paulo
-Mensagem original-
De: Frank W. Zammetti [mailto:[EMAIL PROTECTED]
Enviada em: quarta-feira, 27 de abril de 2005 12:59
Para: Tomcat Users List
Assunto: Re: Nervous about Sessions ...
There *technically* isn't any requirement that things you store in
session be serializable.  However, since some app servers use databases
or file systems to persist session information, and that many times is
implemented using serialization, and since serializable is usually (if
not always) necessary in a clustered environment to replicate the
session between nodes, you probably do for all intents and purposes only
want to store serializable objects in session, just to future-proof
your app.
Yes, you can store simple java types, and no, you do not *have* to use
beans (although I think this is generally considered a best practice in
most cases).  If you do use beans though, you will probably want to make
sure you only use serializable types in the bean, or mark them transient
as Viorel mentioned, as per the point made in the first paragraph above.
But again, there's nothing that says you have to do any of this... if
you KNOW you are only going to run on a single server and if you KNOW
your app server is only storing session in memory, there is nothing that
says any object you put in session, on it's own or by virtue of members
it contains, must be serializable.
--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
David Whitehurst wrote:
If I use the session to store things, 1. Can I use simple java types?
2. Do I have to use Java Beans (extends serializable)?
David Whitehurst
Viorel Dragomir wrote:

Yes.
But you can set some attributes of the objects as [ transient ] to not
be serialized. So you don't have to make all objects in the package
serializable.

Viorel Dragomir
.
..
---

- Original Message - From: David Whitehurst To:
tomcat-user@jakarta.apache.org Sent: Wednesday, April 27, 2005 11:31
Subject: Nervous about Sessions ...
Long ago a multi-client, multi-Oracle application was written using
Struts.  Recently, we had a 4 in 22,000 record data integrity issue.
I found one client implementation that used prepared statements but
the primary key was being used e.g. update mytable set a= ?, b=?
where pri_key =  + pkey +  ' ; ...whoa! I said, called the
developer and we had a talk.
Then, I also found that where we use a HashMap object it is not
synchronized.  I suspect that was the data problem, i.e. two records
saved by two different people, and the data was the same for the
different records in the same Oracle second.
I'm looking for comments about the use of this HashMap on requests
but I'm also nervous now where I use Strings in the session e.g. a
clientname, username, etc. My concern started when I read the posts
about the non-serializable objects in the session.  Do all java
objects placed in the session have to be serializable?
Thanks,
David L. Whitehurst
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Re: Images CSS not loaded after the request passes through a Servlet Filter

2005-04-28 Thread Frank W. Zammetti

Question: are the requests for images and CSS files also going through the
filter?  I'm wondering if those requests are getting forarded to the logon
page too, which obviously wouldn't work.

-- 
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

On Thu, April 28, 2005 1:25 pm, Roberto said:
 Hi,

 I have a small java application, in which a servlet processes the request
 and then
 calls a JSP to present the data. Everything is OK with that configuration.
 Then, I decided
 to create a servlet filter, to redirect every request to that application,
 to a login page first.

 The code of that filter is the following:

 **
 public final class ApplicationFilter implements Filter {
 private FilterConfig _fc = null;

 public void init(FilterConfig filterConfig)
 throws ServletException {
 this._fc = filterConfig;
 }

 public void doFilter(ServletRequest request,
 ServletResponse response,
 FilterChain chain)
 throws IOException,
 ServletException {

 try {
 RequestDispatcher rd =
 _fc.getServletContext().getRequestDispatcher(/login);
 rd.forward(request, response);
 } catch (Exception e) {
 System.out.println(Exception:  + e.getMessage());
 e.printStackTrace();
 }
 }

 -- (the rest was intentionally omitted) --
 ***


 The redirection works great, BUT all images and CSS referenced in the JSP
 file are not
 loaded after the request passes through the filter. The application runs
 perfectly, and takes
 the user to the login screen, and after that, to the application. The
 application does some
 database queries and returns the data correctly. BUT, everything without
 images or the
 styles defined in the CSS file.

 Just to make a test, I put the CSS file contents directly inside the JSP
 file, and it
 worked great. In this case, images were not loaded also...

 The process flows like this:

 Request -- Filter -- login (a servlet) -- login.jsp -- queryDB (a
 servlet) -- queryDB.jsp

 When I disable the filter, in the web.xml file, everything works as would
 be
 expected.

 The configuration in web.xml is OK: all servlets are set, as is the filter
 itself.

 I'm using Tomcat 5.0.28 on a Gentoo Linux system, with POSIX threads and
 kernel
 2.6.9. The hardware is a P IV HT 3.2 Ghz.

 I also checked the archives of this list, but was unable to find any
 reference to a problem
 like this one. Does anyone know what is happening ?

 Regards,
 Roberto



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Re: Concurrency Issue With a SessionListener.

2005-05-03 Thread Frank W. Zammetti

I had to do almost the exact same thing a while back...
I'm not sure what the source of your lockup is, although I can say my 
code synchronized on what would be your activeSessions Set any place it 
was accessed (probably more than I had to frankly)... I'm not even sure 
there would have been concurrency issues anyway frankly, but it seemed 
like a good idea at the time :)

One issue I'm not sure you have thought of though, and I suppose it 
could have to do with the lockup, although I'm not sure how... your list 
of users will be unique to each node in the cluster.

You would have an instance of ActiveUsersListener on each node, and each 
of those would have its own activeSessions Set, so you wouldn't have a 
consolidated list of users on your site, you'd have a list of users on a 
given node in each instance of the listener... further, if a user hits 
one node during logon, and then is directed to another, and during that 
request you try and retrieve the session from activeSessions, it won't 
be there because its in the version of activeSessions on the first node.

Where specifically does the lockup occur, meaning, is it during logon or 
a listing of users?  I'd bet you can see enough in the log to at least 
tell what method your in (well, not as the code is posted... throw some 
log outputs in sessionCreated(), sessionDestroyed() and getActiveUsers() 
so you can at least see the last place you wind up... hell, I'd put log 
messages around every single line in this listener so I could tell 
exactly where it was failing.

Frank
Jacob Champlin wrote:
I am having issues with a SessionListener I have written. The purpose of 
the Listener is to maintain a List of Active Users on the site. Here is 
the code for the Listener.

// BEGIN CODE
public class ActiveUsersListener implements Serializable, 
HttpSessionListener {

public static Set activeSessions = new HashSet();
public void sessionCreated(HttpSessionEvent event) {
activeSessions.add(event.getSession());
}
public void sessionDestroyed(HttpSessionEvent event) {
activeSessions.remove(event.getSession());
}
public static List getActiveUsers() {
List users = new ArrayList();
Iterator sessionIter = activeSessions.iterator();
HttpSession session = null;
EmoUser user = null;
while (sessionIter.hasNext()) {
  session = (HttpSession) sessionIter.next();
  user = (EmoUser) session.getAttribute(EmoUser.SESSION_KEY);
  if (user != null  user.hasLoggedIn()) {
users.add(user);
  }
}
return users;
}
}
// END CODE
I then have a webpage that calls ActiveUsersListener.getActiveUsers() to 
list out all the active users on the site. Note: I don't just store the 
User objects because the user object doesn't get created until the user 
logs in.

So the problem I am having is that this code works fine on a single box 
under Tomcat 5.5.4 . However, as soon as we go into a cluster we get 
lockups in Tomcat. The server is completely unresponsive, and there are 
no log/error messages.

Because of this I am assuming we have a concurrency issue, however I 
have no idea where the problem is.

A few more bits of information, we persist sessions to file system on 
shut down, and we use in memory session replication only when 
session.setAttribute() is called (DirtyFlag).

Thank you in advance for any help.
Jacob Champlin
EMO Corporation
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http://www.omnytex.com
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Re: compile against servlet.jar but must run tomcat with servlet-ap1.jar

2005-05-09 Thread Frank W. Zammetti

As a generality, a compilation should set up all required environment 
setting with each build run.  Those settings should be transitory, i.e., 
should not persists beyond that build.  So in your case you would add 
servlet.jar to the classpath temporarily, compile, and revert the 
classpath (which may happen automatically depending on how you do your 
build).

If you are using an IDE, it will almost certainly handle this for you 
via some sort of classpath setup screen.  An IDE wouldn't be worth much 
if it didn't at least handle this for you :)

If you are working from a plain command line, you have some choices...
First, write a batch file or shell script, depending on your 
environment, to do your compile.  This script would include setting the 
classpath, your javac command, and possibly restoring the classpath to 
what it was before.  Note that if on Windows you execute a batch file, 
the change to classpath is only valid for the life of that command line 
invocation, so there's no need to restore anything (unless you are 
going to sit at a command prompt in the same window and build a couple 
of times).

Second, use Ant or Maven or some other build tool.  I suggest this 
option if you aren't using an IDE for sure.

It sounds like you might be doing some sort of teaching based on the 
fact that it's a getting started project... If your going to be 
teaching anyway, or if you are just learning yourself, I suggest taking 
the dive into Ant right away.  I like Ant myself, some prefer Maven... 
the choice is yours, but I think it's fair to say that Ant is a little 
more popular at this point... Maven might be king a few months down the 
road though.  In any case, neither is difficult at all once you get the 
basics down, and it will save you a lot of trouble in the long-run.

Frank
Fred Cook wrote:

Hi All,
We our new to Tomcat and have a bit of an odd problem.  We are  
developing a getting started project.  We have found that we must 
compile with servlet.jar in our CLASSPATH, but Tomcat will not run with 
servlet.jar in the CLASSPATH.  Tomcat will run with servlet-api.jar, but 
the test program will not compile with servlet-api.jar in the 
CLASSPATH.  To be more specific we get a:

package javax.servlet.http does not exist
error when compiling against servlet-api.jar
Similar errors ocure when running Tomcat with servlet.jar
Changing the CLASSPATH everytime we decide to compile or run isn't much 
fun.  Anybody got an idea on why this is happening, and what the 
solution is.

Tomcat vs 5.5.7
apache vs 2.0.53
RH 8.0
JDK 1.5
-Fred
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Re: Free reporting s/w that works with apache+tomcat

2005-05-10 Thread Frank W. Zammetti

Take a look at DataVision.  I think you'll like it.  I wrote an article 
a while back specifically dealing with using it in web applications. 
Although the article uses servlets and you say your using JSPs (just 
JSP's?) it should still be applicable.

http://www.omnytex.com/articles
Feel free to ping me if you decide to use it and need some help getting 
going beyond the article and included documentation.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
U K Laxmi wrote:
I'm developing a web application using apache+tomcat
on windows 2000 machine. I'm using Ms Access 2003 as
the backend. I'm using JSP for developing web
application. I'm developing some web based reports in
HTML. But when i export them to Excel, it doesn't look
exactly same as that of HTML report. Moreover i need
some header and footer information appear in the
report. That i'm unable to achieve using JSP and HTML.
So, i'm looking for a free reporting software that can
meet above functionality and can work with
apache+tomcat. If anyone know any work worunds for my
problem, pls inform me. It will be a great help to me.
Thank you.
		
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Re: Free reporting s/w that works with apache+tomcat

2005-05-10 Thread Frank W. Zammetti

Hi,
CSV files don't generally contain header and footer information... you 
can get column headers in the first row, that's about it.  I don't 
believe DataVision will export to Excel natively, but check the docs in 
case I'm wrong.

Do you really mean header and footer in the sense of a Word document? 
It's a bit unusual to have such a thing in an Excel document (although 
not at all unheard of), so I'm wondering if maybe you mean something a 
little different, i.e., maybe just column headers and some sort of totals?

Frank
U K Laxmi wrote:
Thank you for the information. I read your report and
it looks interesting. I went to DataVision web site
and found that it can export comma separated files ie.
CSV file. Will it be possible to retain header and
footer information with a .CSV file? I basically want
excel files as the report output. B'coz the end user
needs to send to those reports to it's vendors. Excel
is the most desired format for them. Pls give your
feedback on this before i start implementing on this.
Thank you.
--- Frank W. Zammetti [EMAIL PROTECTED] wrote:
Take a look at DataVision.  I think you'll like it. 
I wrote an article 
a while back specifically dealing with using it in
web applications. 
Although the article uses servlets and you say your
using JSPs (just 
JSP's?) it should still be applicable.

http://www.omnytex.com/articles
Feel free to ping me if you decide to use it and
need some help getting 
going beyond the article and included documentation.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
U K Laxmi wrote:
I'm developing a web application using
apache+tomcat
on windows 2000 machine. I'm using Ms Access 2003
as
the backend. I'm using JSP for developing web
application. I'm developing some web based reports
in
HTML. But when i export them to Excel, it doesn't
look
exactly same as that of HTML report. Moreover i
need
some header and footer information appear in the
report. That i'm unable to achieve using JSP and
HTML.
So, i'm looking for a free reporting software that
can
meet above functionality and can work with
apache+tomcat. If anyone know any work worunds for
my
problem, pls inform me. It will be a great help to
me.
Thank you.
		
__ 
Yahoo! Mail Mobile 
Take Yahoo! Mail with you! Check email on your
mobile phone. 

http://mobile.yahoo.com/learn/mail 



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Omnytex Technologies
http://www.omnytex.com
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Re: Sessions and keep-alives

2005-05-12 Thread Frank W. Zammetti

If you can use Javascript (and can require it), what you could do is set a 
timer in app B's onLoad event to call a Javascript function in app A from app B 
(parent.myFunction();)... This function could refresh whatever the current page 
is in some interval less than your timeout period.  You'll have to ensure all 
pages of app A have that refresh function in page-scope, and that all pages in 
B set that timer and make the call.

If a full-page refresh isn't feasible, you can make an AJAX call to app A that 
does really nothing, but that should be enough to keep the session from timing 
out.

Does that all make sense? (I'm not sure I described it well)

Frank W. Zammetti

-Original Message-
From: Patrick Lacson[EMAIL PROTECTED]
Sent: 5/13/05 12:56:43 AM
To: Tomcat Users Listtomcat-user@jakarta.apache.org
Subject: Re: Sessions and keep-alives
  I've considered iframes, but unfortunately not an option for us.

From what I understand AJAX can make async calls to the HTTP server
from the webapplication only, not on behalf of another.  So if the
popup application is webapp B, and the parent webapp A, how can I call
the webapp A server from webapp B for the keep-alive?


On 5/12/05, Tim Funk [EMAIL PROTECTED] wrote:
 The simplest kludge is an iframe that is hidden and uses a META refresh.
 
 Or look at using ajax.
 
 -Tim
 
 Patrick Lacson wrote:
 
  hi All!
 
  I'm involved in a project that integrates two disparate web
  applications: webapp A is using WebSphere and webapp B is using
  Tomcat.
 
  The integration involves Single Sign On, with webapp A being the
  primary webapp from which webapp B is launched.  webapp B is launched
  as a popup-window.
 
  My question is: how can i ensure that while the user is working on the
  webapp B popup, the parent window webapp A, does not time-out?
 
  Thanks in advance!
 
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-- 
Patrick

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Re: Sessions and keep-alives

2005-05-12 Thread Frank W. Zammetti

If you can use Javascript (and can require it), what you could do is set a 
timer in app B's onLoad event to call a Javascript function in app A from app B 
(parent.myFunction();)... This function could refresh whatever the current page 
is in some interval less than your timeout period.  You'll have to ensure all 
pages of app A have that refresh function in page-scope, and that all pages in 
B set that timer and make the call.

If a full-page refresh isn't feasible, you can make an AJAX call to app A that 
does really nothing, but that should be enough to keep the session from timing 
out.

Does that all make sense? (I'm not sure I described it well)

Frank W. Zammetti

-Original Message-
From: Patrick Lacson[EMAIL PROTECTED]
Sent: 5/13/05 12:56:43 AM
To: Tomcat Users Listtomcat-user@jakarta.apache.org
Subject: Re: Sessions and keep-alives
  I've considered iframes, but unfortunately not an option for us.

From what I understand AJAX can make async calls to the HTTP server
from the webapplication only, not on behalf of another.  So if the
popup application is webapp B, and the parent webapp A, how can I call
the webapp A server from webapp B for the keep-alive?


On 5/12/05, Tim Funk [EMAIL PROTECTED] wrote:
 The simplest kludge is an iframe that is hidden and uses a META refresh.
 
 Or look at using ajax.
 
 -Tim
 
 Patrick Lacson wrote:
 
  hi All!
 
  I'm involved in a project that integrates two disparate web
  applications: webapp A is using WebSphere and webapp B is using
  Tomcat.
 
  The integration involves Single Sign On, with webapp A being the
  primary webapp from which webapp B is launched.  webapp B is launched
  as a popup-window.
 
  My question is: how can i ensure that while the user is working on the
  webapp B popup, the parent window webapp A, does not time-out?
 
  Thanks in advance!
 
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Patrick

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Re: Sessions and keep-alives

2005-05-13 Thread Frank W. Zammetti

I'm curious how this would work?  If I open a page with an invisible GIF,
there's no way (without scripting and such) to have the GIF refresh,
right?  Or is there something I'm missing?

You can set a meta refresh on the page, but not the GIF itself, as far as
I know anyway.

-- 
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

On Fri, May 13, 2005 12:04 pm, Tim Diggins said:
 I'd just include this invisible gif on every page (request) of webapp B.
 (bone-headed solution, but why get more tricksy until you need it).

 -- Tim

 Patrick Lacson wrote:
 Interesting solution Tim.. so webapp B would invoke this invisible gif
 from webapp A on an interval basis?

 -P

 On 5/13/05, Tim Diggins [EMAIL PROTECTED] wrote:

Hi Patrick -

If not an iframe, why not a gif... There's nothing (in principle I
think*) stopping you having a jsp page that returns a (tiny, invisible)
gif (with the right mimetype) and with appropriate expires/cache-control
headers to make sure that it gets got each time.  That's the way some
web-counters work, for example, and I can't see it would create a
problem... (I don't however know whether you can maintain two session
cookies at the same time... Would work however with a param-based
 session).

--Tim

* I have done this in similar kinds of situations with python  php, but
not tomcat.


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Re: delete temporary content after session timeout

2005-05-14 Thread Frank W. Zammetti

Write a SessionListener... it has two methods, one that fires when a 
session is created, one when it is destroyed.  That should do the trick 
for you.  That's not a Tomcat-specific solution either, so it should be 
rather portable should you ever need to move to another app server.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Bob Wobbler wrote:
Hi,
I have an app that uploads user files in a temporary folder. I want to 
delete them when the session ends. I know I could solve this with a 
cron-job, but I'm looking for a way to solve it with Tomcat.

Does anyone have an idea how to solve it?
Thx for your help in advance,
cheers,
Robert
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Re: delete temporary content after session timeout

2005-05-14 Thread Frank W. Zammetti

Let's see...
(1) You are correct, it's nothing more than an entry in web.xml. 
Remember, this isn't a Tomcat-specific thing, it's a J2EE thing (servlet 
spec specifically I think), so it's YOUR APP'S web.xml.  The entry is 
simply:

listener
listener-classcom.company.app.MySessionListener/listener-class
/listener
Assuming that class is available to the classloader, your all set.
(2) I'm not too familiar with the Spring framework, but since it's still 
built on top of the servlet spec, this would apply just the same, it 
should be independant of app server and framework in use.  Spring may 
have it's own mechanism for doing this, but given the choice I'd chose 
the standard approach, which is a listener.

(3) I don't have any good references handy, but just Googling 
SessionListener will turn up plenty of hits.  Just to save you some 
time, here's the basic structure of a SessionListener class:

package com.company.app.MySessionListener
import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpSessionEvent;
public class MySessionListener implements HttpSessionListener {
  /**
   * This method is called by the servlet container just after http 
session is
   * created.
   *
   * @param bevent/b HttpSessionEvent
   */
  public void sessionCreated(HttpSessionEvent event) {
  }

  /**
   * This method is called by the servlet container just before http 
session is
   * destroyed.
   *
   * @param bevent/b HttpSessionEvent
   */
  public void sessionDestroyed(HttpSessionEvent event) {
  }

}
Couldn't be simpler!  You can do event.getSession() in both if you need 
to do anything with the session (like, for the OP, if you have a 
reference to the user ID who's directory you want to purge of temporary 
files).

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Tim Diggins wrote:
that sounds very useful, not something I've done before -- can I ask a 
few questions -

1) how does one bind that into Tomcat -- declare a session listener in 
(I presume) web.xml?

2) as I'm using Spring Framework, is this still relevant (or is there a 
spring-specific way of binding in a session listener --- sorry, ought to 
ask that on a spring list...)

3) can you recommend the best reference material / sites on managing 
sessions (standard tomcat docs seem to have nothing on sessions I can 
find.)

Tim
Frank W. Zammetti wrote:
Write a SessionListener... it has two methods, one that fires when a 
session is created, one when it is destroyed.  That should do the 
trick for you.  That's not a Tomcat-specific solution either, so it 
should be rather portable should you ever need to move to another app 
server.


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Re: How to do Downtime with a Apache/Tomcat webapp

2005-05-17 Thread Frank W. Zammetti

I had a similar requirement in my app... We had a two-hour window per 
day when the app was unavailable because background tasks were 
processing.  The server was still up, and so was the app technically, 
but it was not available.

I wrote a filter to take care of this.  I had a flag in application 
context to tell if the app was up or not too, so that if I had to make 
the app unavailable during a time when it normally was available, I just 
set the flag.  I also defined a single user that was still allowed to 
get in (another context parameter).  This works out great.

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com
Len Popp wrote:
I've been thinking about the same problem, but I haven't gotten around to 
working on it seriously.
 How about this: Instead of fiddling with the JkMount directives in Apache, 
swap the web.xml in your Tomcat app so it points to a minimal servlet that 
returns the Out of service page for all requests.
 Does that sound like it would work? It would be less disruptive because you 
don't have to restart Apache (if there's more to the web site than the one 
Tomcat app). Plus this will work with stand-alone Tomcat.

On 5/15/05, Richard Mixon (qwest) [EMAIL PROTECTED] wrote: 

I'm curious how folks handle letting users know that their webapp is
down when doing maintenance.
We've got a pretty standard setup. Our informational/static site is
served by Apache 2.0.x. We use mod_jk to link to a page in our
webapplications, triggering CMA for authentication and login. We run
Tomcat 5.5.x. Although we actually have Tomcat clustered, there are
still times when we need to make the application unavailable. (i.e.
doing database schema changes, etc.).
I would like for a page to be displayed that says the application is
temporarily not available.
So, what's the best way to do this?
One way I can think of is to modify the JkMount directives so that may
context name was not mapped to Tomcat, but instead to a static page -
the just do a restart. Trouble is some of our users have bookmarks into
various pages/actions in the application - we would somehow have to mapp
all pages that began with the context name to this single page. This
sounds a bit messy.
Is there a more straightforward way of doing this?
Thank you - Richard
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Re: Can a servlet receive its own request?

2005-05-18 Thread Frank W. Zammetti

You *probably* could do this... I'm not 100% sure.

What I *AM* sure about though is that this would be pretty ugly :)

I'm not sure what you mean by Outside server processes request and
responds with POST response (also via https). though...

Is the idea that the request to the outside server is to be asychronous,
or will your servlet be awaiting a reply?  If the former, then you
probably can go with your approach and it won't be all that ugly... it's
essentially nothing more than another request coming in to the servlet,
same as always, your just going to process it differently...  as long as
you get enough information back to be able to complete the transaction,
it should work fine.  Just treat the initial request to your servlet and
the response back from the outside server as two separate requests and you
should be fine.

If however, as I suspect might be the case, your servlet is going to
actually be awaiting a reply from the outside server, then you should look
at using Commons HTTPClient.  I'm relatively sure it supports SSL
connections, and then all your doing is making a remote request, awaiting
the response and processing accordingly.  It'd be just like using the
standard URL object, but it's more robust than that.

-- 
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

On Wed, May 18, 2005 11:58 am, Michael Mehrle said:
 Simple question, but it's driving me nuts. I really don't want to get into
 the whole web service business - all I need is for a servlet to be the
 recipient of its own request. Or - in other words - can a servlet act like
 a
 web browser - just without the GUI?

 Use case:

 - Servlet issues https request to an outside server (via
 getServletContext().getRequestDispatcher(https://www.someoutsideserver/) )
 - Outside server processes request and responds with POST response (also
 via
 https).
 - Servlet [somehow] is able to be the recipient of the response.
 - Servlet parses the response and stores data to the database.

 Notes:

 - The servlet is not the default servlet on that tomcat instance.
 - Everything happens via https and I expect the outside server will listen
 on 443 and tomcat on 8443

 ANY suggestions would be very helpful - this seems to be a tricky one.

 TIA,

 Michael



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Re: Can a servlet receive its own request?

2005-05-18 Thread Frank W. Zammetti

I don't think saying it's silly is really helpful, or even necessarily
accurate...

If the idea is that the request to the outside server is meant to to
asynchronous, i.e., maybe it feeds a queue or something, then it's a
reasonable model.  It doesn't sound like that's what the OP meant, but if
it was, it would be reasonable.

Of course, even in that case the servlet is not receiving its own
request, it is simply making a request, at which point it is done, and at
some future time receiving a request with the results.

I agree with you that Web Services need not be as complicated as some make
it out to be... no need to involve SOAP or XML-RPC or any other of the
numerous alphabet soup entries.  I was doing Web Services seven years
ago, long before I heard the term.  I suppose you could say that's not
standards-compliant, which is one of the goals behind Web Services of
course... if everyone used the same mechanisms than theoretically it would
all be interoperable with no effort, and that's not the case if you
essentially cook up your own protocols, but since the reality is that even
following the standards you rarely get that right now, it's not such a
problem :)

-- 
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

On Wed, May 18, 2005 2:53 pm, Will Hartung said:
 From: Michael Mehrle [EMAIL PROTECTED]
 Sent: Wednesday, May 18, 2005 8:58 AM


 - Servlet issues https request to an outside server (via
 getServletContext().getRequestDispatcher(https://www.someoutsideserver/)
 )
 - Outside server processes request and responds with POST response (also
 via
 https).
 - Servlet [somehow] is able to be the recipient of the response.
 - Servlet parses the response and stores data to the database.

 Your problem is with the whole model.

 There is no reason why a Servlet can't send an HTTP(S) request to another
 server.

 But the server that you are making the request shouldn't be making an
 independent POST back to you, rather it should just send you the data you
 want back as the reply body. You then parse the reply and move on.

 IF you insist that the reply be in the manner of a POST from the other
 server (really really silly IMHO), then, simply, you need to make the
 request to the other server be the last thing your Servlet does. Then when
 the POST comes back, you pick up where you left off, tracking your state
 through a request parameter.

 So, your Servlet may start with a request like:
 http://otherserver.com/processData?mysession=123stage=1

 Then the otherserver replies with a POST to:
 http://yourserver.com/yourServlet?mysession=123stage=2

 You use the mysession information to maintain your state between requests.
 But the key is that your servlet ends each time, and Tomcat then restarts
 it
 when the POST comes back.

 It's still a silly idea. You don't need Webservices, SOAP, XML-RPC, etc to
 talk to another server via HTTP. You can easily stream serialized Java
 objects to each other if you want, use the simple Java Properties file
 format for your responses, etc. I think if you have control over both
 servers, WEB RPC can be very simple for a limited domain. If you don't
 have control over the other server, then you do what you have to do.

 I mean, seriously:

 public class AddNumberServlet extends HttpServlet {
 public void doGet(HttpServletRequest request, HttpServletResponse
 response)
 throws ServletException, IOException {
 PrintWriter out = response.getWriter();
 String arg1 = request.getParameter(arg1);
 String arg2 = request.getParameter(arg2);
 int i1 = Integer.parseInt(arg1);
 int i2 = Integer.parseInt(arg2);
 int result = i1 + i2;
 out.println(answer= + result);
 }
 }

 public class RequesterServlet extends HttpServlet {
 public void doGet(HttpServletRequest request, HttpServletResponse
 response)
 throws ServletException, IOException {
 PrintWriter out = response.getWriter();

 URL reqURL = new
 URL(http://otherserver/AddNumberServlet?arg1=2arg2=4);
 Properties result = new Properties();
 result.load(reqURL.openStream());
 String answer = result.get(answer);
 out.println(HTMLBODYWhen you add up 2 and 4 you get  +
 answer
 + /BODY/HTML);
 }
 }

 There. Instant web service.

 Error checking and robustness are left as an exercise for the reader, but
 you can see that you don't need a 500 page book to get some data from
 another web server.

 Not to discount the XML-RPC and SOAPs, they have their place most
 certainly.
 No doubt XML-RPC started just like this and grew from there (and then into
 SOAP), but its just a simple example of how easy this can be when you have
 control over the whole shebang.

 Regards,

 Will Hartung
 ([EMAIL PROTECTED])


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Re: Where do -Xms32m, -Xmx256m, and -Xrs go in the Tomcat 5.0.28 batch files?

And just to let you know, should you ever need/want to run Tomcat as a
service, it's a different story at that point.  At least on Windows, those
settings are stored in the registry.  If you ever need to go down that
road, I highly suggest a look at Tomcat Service Manager:

http://web.bvu.edu/staff/david/index.jsp?section=softwaresubsection=tcservcfgpage=overview

Of course, if your not on Windows or not running as a service, you already
have your answer :)

-- 
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

On Mon, May 23, 2005 10:11 am, Dakota Jack said:
 Thanks for the assistance.

 I finally figured this out, for future people trying to find the same
 answer.  The environmental variables at the top of catalina.bat can be
 set there.  So, I added:

 SET CATALINA_OPTS=-Xms512m -Xmx512m -Xrs

 after


 rem
 rem   CATALINA_OPTS   (Optional) Java runtime options used when the
 start,
 rem   stop, or run command is executed.
 rem

 in catalina.bat.



 On 5/23/05, Parsons Technical Services [EMAIL PROTECTED]
 wrote:
 Jack,

 To use the batch files you need to set it as an Environment Variable.
 The
 catalina.bat file will the pick it up and add it to command line.

 If you are wanting to do some quick testing, I think you MAY be able to
 include it on the command line with startup.bat. I don't run on Windows
 so I
 can't test it.

 If you look in the catalina.bat you will see the comments at the top
 talking
 about the variables. If you look in startup.bat you will see where it
 picks
 up the command line variables.

 The .sh files are the nix OS equivalent to the Windows .bat files.

 Doug

 - Original Message -
 From: Edao, Aliye [EMAIL PROTECTED]
 To: Dakota Jack [EMAIL PROTECTED]
 Cc: Tomcat Users List tomcat-user@jakarta.apache.org
 Sent: Monday, May 23, 2005 2:57 AM
 Subject: AW: Where do -Xms32m, -Xmx256m, and -Xrs go in the Tomcat
 5.0.28
 batch files?


 Hi Jack,

 The answer is CATALINA_HOME/bin/catalina.sh

 CATALINA_OPTS=-Xmx512m -Xss1024k  -XX:+PrintGCDetails -server ...


 
 Mit freundlichem Gruß / kind regards

 SBS ORS GD AHS OA42
 Otto-Hahn-Ring 6
 D - 81739 München
 Tel. (089) 636-41024
 Fax (089) 636-49347

 Dr. Aliye Edao
 mailto:[EMAIL PROTECTED]



 -Ursprüngliche Nachricht-
 Von: Dakota Jack [mailto:[EMAIL PROTECTED]
 Gesendet: Montag, 23. Mai 2005 08:48
 An: Tomcat Users List
 Betreff: Where do -Xms32m, -Xmx256m, and -Xrs go in the Tomcat 5.0.28
 batch
 files?


 I am running out of memory when running some imaging ops with Tomcat
 5.0.28 and need to set the java command with the attributes -Xms32m,
 -Xmx256m, and -Xrs.  However, danged if I can figure out how to do
 that.  I am using the simple startup.bat and shutdown.bat.  Where is
 the place I plugin with those values?  Thanks?
 --
 You can lead a horse to water but you cannot make it float on its
 back.
 ~Dakota Jack~

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 For additional commands, e-mail: [EMAIL PROTECTED]





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 --
 You can lead a horse to water but you cannot make it float on its back.
 ~Dakota Jack~

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Re: Where do -Xms32m, -Xmx256m, and -Xrs go in the Tomcat 5.0.28 batch files?

http://web.bvu.edu/staff/david/index.jsp?section=softwaresubsection=tcservcfgpage=downloads

-- 
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

On Mon, May 23, 2005 10:56 am, Dakota Jack said:
 Hi, again, Frank,

 Where can I get a copy of the code/binaries for Java Service Manager
 (the update of Tomcat Service Manager)?  I went to this site but there
 seems to be no reference to any downloads.

 On 5/23/05, Frank W. Zammetti [EMAIL PROTECTED] wrote:
 And just to let you know, should you ever need/want to run Tomcat as a
 service, it's a different story at that point.  At least on Windows,
 those
 settings are stored in the registry.  If you ever need to go down that
 road, I highly suggest a look at Tomcat Service Manager:

 http://web.bvu.edu/staff/david/index.jsp?section=softwaresubsection=tcservcfgpage=overview

 Of course, if your not on Windows or not running as a service, you
 already
 have your answer :)

 --
 Frank W. Zammetti
 Founder and Chief Software Architect
 Omnytex Technologies
 http://www.omnytex.com

 On Mon, May 23, 2005 10:11 am, Dakota Jack said:
  Thanks for the assistance.
 
  I finally figured this out, for future people trying to find the same
  answer.  The environmental variables at the top of catalina.bat can be
  set there.  So, I added:
 
  SET CATALINA_OPTS=-Xms512m -Xmx512m -Xrs
 
  after
 
 
  rem
  rem   CATALINA_OPTS   (Optional) Java runtime options used when the
  start,
  rem   stop, or run command is executed.
  rem
 
  in catalina.bat.
 
 
 
  On 5/23/05, Parsons Technical Services
 [EMAIL PROTECTED]
  wrote:
  Jack,
 
  To use the batch files you need to set it as an Environment Variable.
  The
  catalina.bat file will the pick it up and add it to command line.
 
  If you are wanting to do some quick testing, I think you MAY be able
 to
  include it on the command line with startup.bat. I don't run on
 Windows
  so I
  can't test it.
 
  If you look in the catalina.bat you will see the comments at the top
  talking
  about the variables. If you look in startup.bat you will see where it
  picks
  up the command line variables.
 
  The .sh files are the nix OS equivalent to the Windows .bat files.
 
  Doug
 
  - Original Message -
  From: Edao, Aliye [EMAIL PROTECTED]
  To: Dakota Jack [EMAIL PROTECTED]
  Cc: Tomcat Users List tomcat-user@jakarta.apache.org
  Sent: Monday, May 23, 2005 2:57 AM
  Subject: AW: Where do -Xms32m, -Xmx256m, and -Xrs go in the Tomcat
  5.0.28
  batch files?
 
 
  Hi Jack,
 
  The answer is CATALINA_HOME/bin/catalina.sh
 
  CATALINA_OPTS=-Xmx512m -Xss1024k  -XX:+PrintGCDetails -server ...
 
 
  
  Mit freundlichem Gruß / kind regards
 
  SBS ORS GD AHS OA42
  Otto-Hahn-Ring 6
  D - 81739 München
  Tel. (089) 636-41024
  Fax (089) 636-49347
 
  Dr. Aliye Edao
  mailto:[EMAIL PROTECTED]
 
 
 
  -Ursprüngliche Nachricht-
  Von: Dakota Jack [mailto:[EMAIL PROTECTED]
  Gesendet: Montag, 23. Mai 2005 08:48
  An: Tomcat Users List
  Betreff: Where do -Xms32m, -Xmx256m, and -Xrs go in the Tomcat 5.0.28
  batch
  files?
 
 
  I am running out of memory when running some imaging ops with Tomcat
  5.0.28 and need to set the java command with the attributes -Xms32m,
  -Xmx256m, and -Xrs.  However, danged if I can figure out how to do
  that.  I am using the simple startup.bat and shutdown.bat.  Where is
  the place I plugin with those values?  Thanks?
  --
  You can lead a horse to water but you cannot make it float on its
  back.
  ~Dakota Jack~
 
  -
  To unsubscribe, e-mail: [EMAIL PROTECTED]
  For additional commands, e-mail: [EMAIL PROTECTED]
 
 
  -
  To unsubscribe, e-mail: [EMAIL PROTECTED]
  For additional commands, e-mail: [EMAIL PROTECTED]
 
 
 
 
 
  -
  To unsubscribe, e-mail: [EMAIL PROTECTED]
  For additional commands, e-mail: [EMAIL PROTECTED]
 
 
 
 
  --
  You can lead a horse to water but you cannot make it float on its
 back.
  ~Dakota Jack~
 
  -
  To unsubscribe, e-mail: [EMAIL PROTECTED]
  For additional commands, e-mail: [EMAIL PROTECTED]
 
 




 --
 You can lead a horse to water but you cannot make it float on its back.
 ~Dakota Jack~



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Re: How to change the value of a form's text field by scriplet?


You might not be asking this, but...

Scriplets execute on the server, not on the client.  The results of a 
scriplet are in essence inserted into the response.


So in that regard, no, you can't use a scriplet to change the value of a 
text field as you would with Javascript because Javascript executes on 
the client *AFTER* the response has been completely rendered and 
returned to the broser, while a scriplet executes *WHILE* the response 
is being rendered and *BEFORE* it is returned to the client.


Does that answer the question, or did I misinterpret?

Frank

Cassius V. de Magalhaes wrote:

Hello,

I would like to change the value of a form's text field by scriplet, is it 
possible, please?
Through Javascript, I can use the form name plus the name of the field, for 
example,
myform.address.value='xxx'. I know I can do myform.address.value='%= something %', 
where something is a
scriplet variable declared previously. Is it possible to change the value of a 
form field inside of a scriplet
just as we can by a javascript code, please?

TIA,
Vinicius.


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--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com


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Re: How to change the value of a form's text field by scriplet?


I should also mention, you can certainly do something like this:

script
function changeIt() {
  myForm.myField.value = %=someValue%;
}
/script

...but that's not much different than just setting the value of the 
field with a scriplet.  However, if you perhaps have some discrete 
values that you want to be able to change the field to, like maybe 
something like a previous value button, and you have the value at the 
time the JSP is interpreted, you can do this and just call changeIt() in 
response to onClick() of the button.  That's something of a hybrid.


Frank

Frank W. Zammetti wrote:

You might not be asking this, but...

Scriplets execute on the server, not on the client.  The results of a 
scriplet are in essence inserted into the response.


So in that regard, no, you can't use a scriplet to change the value of a 
text field as you would with Javascript because Javascript executes on 
the client *AFTER* the response has been completely rendered and 
returned to the broser, while a scriplet executes *WHILE* the response 
is being rendered and *BEFORE* it is returned to the client.


Does that answer the question, or did I misinterpret?

Frank

Cassius V. de Magalhaes wrote:


Hello,

I would like to change the value of a form's text field by scriplet, 
is it possible, please?
Through Javascript, I can use the form name plus the name of the 
field, for example,
myform.address.value='xxx'. I know I can do 
myform.address.value='%= something %', where something is a
scriplet variable declared previously. Is it possible to change the 
value of a form field inside of a scriplet

just as we can by a javascript code, please?

TIA,
Vinicius.


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.





--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com


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Re: Adding content/JSPs on the fly

2005-05-27 Thread Frank W. Zammetti


Could you instead store the JSP in a database?

Let's say you have a table with the following structure:

jsp_nameString
jsp_content BLOB

jsp_name is your primary key and is literally a JSP name.

Now, create a servlet filter that examines the path that was requested 
and pulls out the file name part... so the path might be 
/my/app/page1.jsp, you just want the page.jsp part.


Now, get the BLOB from the database based on that JSP name.  Convert the 
BLOB to a string and stick it in request, then forward to a JSP that is 
the following:


%=(String)request.getAttribute(theJSPContent)%

And that's that.  You could create a screen specifically for uploading a 
JSP and storing it in the database.


Would something like this suite your needs?  I realize it's not as 
straight-forward as one might like, but it's not too bad either.


--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

Will Hartung wrote:

From: Steve Kirk [EMAIL PROTECTED]
Sent: Friday, May 27, 2005 11:44 AM




It sounds reasonable, but probably isn't tested or by design, so


probably


best to just have a go.  Re portability, the best advice I can offer is an
old chestnut: read the servlet spec.  This is particularly relevant in


this


case.  The spec is generally pretty good at telling you you pretty
accurately if (a) what you want to do should/must be supported or (b) what
you want do do is forbidden.  Of course there are some areas that it does
not have a view either way on, but I find it to be an invaluable


document -


I have it on shortcut from my taskbar and consult it often.  It's at least
as useful as the javadocs or TC docs.

For those of you that don't know where to find it, it's here, under
specifications.
http://java.sun.com/products/servlet/reference/api/index.html

Choose the servlet spec version appropriate to your TC version as


described


in the table on the tomcat home page:
http://jakarta.apache.org/tomcat/index.html



I'm reasonably familiar with the specification. One of the notable bits
about it is simply the fact that within the spec, you're pretty much not
guaranteed writeable access to the file system at all (save for a temporary
area, and it's simply that -- temporary). But the reality is that most
engines give you access to the disk that way.



Just one more specific point on your note Will - I would have thought if
anything that you want it to be a precondition that the webapp NOT be
deployed as a war.  I've a feeling that if TC explodes the war, then it
might not check the exploded FS for changes.  Don't take this as gospel
though, this is a hazy half-remembered bit of info.



As far as I know, the Servlet spec doesn't have a deployment method outside
of a WAR. It's pretty much a container behavior to actually explode the WAR
on to the file system, yet, most obviously do for performance reasons.

But it does bring up a basic problem, for example, if by some fluke the app
is redeployed, all of that new data is blasted away by the WAR..that would
be Bad.

But I can't see another (easy) way to create JSPs on the fly, or in fact to
create any other content that can be served directly the server.

It's an annoying nit of the spec, to me, that it doesn't expose this
behavior to the developer. For example, unlike EJBs (which has a specified
limitation on accessing the disk), the Servlet spec does allow you to access
the disk, though perhaps not within the WAR hierarchy. But, there is no way
to, say, forward to a static resource that the server can then handle in
its own internally optimal way. Rather, I have to open the static
resource, determine the content type (I can get that from the Servlet spec),
and then feed it into the output stream, when in fact it would simply be
easier to do req.serveStatic(/tmp/mynewgraphic.gif) or some such thing,
or be able to forward outside of the web app (i.e. to a actual file rather
than a URL).

Simply, the application structure and such are pretty much isolated from the
developer. I can't add anything dynamically to the security domain, for
example, which means if I want that kind of capability in my application, I
have to essentially implement ALL of the container security -- mapping, role
checks, etc. Container security is an all or nothing. Be happy with its
limited funcitonality or dump it entirely.

So, now if I want dynamic templating in my Webapp, I, technically, have to
dump JSP completely and switch to something like Velocity. All of the power
of JSP, tag libraries, etc. is gone. I imagine that I could mimic the JSP
environment, compile the JSP myself, compile the java myself, load the class
myself and feed the output into the standard output stream, but that seems
like a silly wheel to reinvent when I have a full container here that DOES
THAT ALREADY, doncha think?

Mind, I may still just Do It, open up paths to the disk and plonk files and
JSPs in place and see what happens, but it's a flaming hoop

Re: Cross-site scripting vulnerability

2005-05-27 Thread Frank W. Zammetti


I notice the more... at the end of that... do you have the more by chance?

Cross-site scripting (CSS) vulnerabilities are, generally-speaking, 
concerned with situations where a server-side process generates HTML 
dynamically and there is a possibility of input data that has not been 
scrubed of certain dangerous characters (i.e., ()%, etc.) being 
inserted into the generated code.  Proper crafting of such input data 
can result in code being executed as trusted when it clearly should not be.


(As amazing as it seems, I found the following page from Microsoft, of 
all sources!, to be a good explanation of the problem: 
http://support.microsoft.com/default.aspx?scid=kb;en-us;252985)


As such, a tool that says a server is an enabling vector for such a 
vulnerability is not being especially helpful because virtually *any* 
server-side code that doesn't deal with such characters is potentially 
an enabling vector.  If it narrows down the location of the apparent 
vulnerability, i.e., specified a path it tested maybe, it might point at 
something legitimately of concern.  If it's just saying Hey, Tomcat 
could be used to craft a CSS hack, well, yes, it COULD, but then so 
could *anything* server-side that generates HTML!


(Ironically, I spent most of today dealing with a servlet filter written 
by another team at my company that deals with cross-site scripting 
vulnerabilities, but which seems to have some unexpected side-effects, 
so I had to get up to speed on CSS vulnerabilities in a hurry!)


Frank

Narses Barona wrote:

Our security tool produces the following warning against Tomcat 4.1.29 :

[HTTP/8080/TCP] Server is an enabling vector for cross-site scripting 
exposure in clients [trace-1]. More...


I seached the mailing list and found several references to cross-site
scripting.  Based on the information, I am lead to believe that the
problem is not with the product, but with the examples or some other 
non-critical piece of code.  I have removed the 
jakarta-tomcat-4.1.29/webapps/examples directory and its' content, but

the problem persists.  Is there some other file/directory that needs
to be removed to fix this problem?  I noticed one reference to a 
SnoopServlet, but can't find any file by that name.


Narses Barona




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Validating a session

This might seem bizarre, but...

Assume that a request contains a session ID as a parameter.  Is there a
way *programmatically* to validate that session ID?

In other words, the query string contains the session ID, and in a servlet
I need to be able to ask the container if it is valid or not.  But, for
reasons that would probably make your head spin if I explained, I cannot
simply allow the container to do it, I need to be able to do it from my
own code.

Moreover, this can't be a Tomcat-specific solution.

Any takers? :)

-- 
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Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

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Simple question on HTTP return codes

I fear I should know this answer, but...

How can one, from a servlet (or Struts Action maybe) throw a specific
HTTP return code?  I need to return a 403 from a servlet if certain things
are not present in the request... is it just a matter of setting a
particular header, or is there something to throw, like an exception?

Thanks all!

-- 
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

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Re: Simple question on HTTP return codes

Yep, I *should* have known that :)...

The sendError() method of HttpServletRequest does it.  Sorry for wasted
bandwidth!

-- 
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

On Tue, May 31, 2005 3:13 pm, Frank W. Zammetti said:
 I fear I should know this answer, but...

 How can one, from a servlet (or Struts Action maybe) throw a specific
 HTTP return code?  I need to return a 403 from a servlet if certain things
 are not present in the request... is it just a matter of setting a
 particular header, or is there something to throw, like an exception?

 Thanks all!

 --
 Frank W. Zammetti
 Founder and Chief Software Architect
 Omnytex Technologies
 http://www.omnytex.com



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Re: Validating a session

Thanks Jack, that's a good reference.  It didn't really answer my specific
question, not that I could see immediately anyway, but I solved the
problem a different way anyhow, so it's all good.  I bookmarked that
anyway, could be a good reference down the road for something.

-- 
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

On Tue, May 31, 2005 2:51 pm, Dakota Jack said:
 The following is a pretty good, even if ugly, article on session ids,
 Frank.  Very comprehensive and it should cover in some part whatever
 you are working on:

 http://www.technicalinfo.net/papers/WebBasedSessionManagement.html

 On 5/31/05, Frank W. Zammetti [EMAIL PROTECTED] wrote:
 This might seem bizarre, but...

 Assume that a request contains a session ID as a parameter.  Is there a
 way *programmatically* to validate that session ID?

 In other words, the query string contains the session ID, and in a
 servlet
 I need to be able to ask the container if it is valid or not.  But, for
 reasons that would probably make your head spin if I explained, I cannot
 simply allow the container to do it, I need to be able to do it from my
 own code.

 Moreover, this can't be a Tomcat-specific solution.

 Any takers? :)

 --
 Frank W. Zammetti
 Founder and Chief Software Architect
 Omnytex Technologies
 http://www.omnytex.com

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 ~Dakota Jack~

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Re: Simple question on HTTP return codes


Cool, good to know there is a difference.  Thanks!

Frank

Dakota Jack wrote:

Just a small note, Frank.  You use sendError(int sc) for errors but
setStatus(int sc) for codes that are not errors.

On 5/31/05, Frank W. Zammetti [EMAIL PROTECTED] wrote:


Yep, I *should* have known that :)...

The sendError() method of HttpServletRequest does it.  Sorry for wasted
bandwidth!

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

On Tue, May 31, 2005 3:13 pm, Frank W. Zammetti said:


I fear I should know this answer, but...

How can one, from a servlet (or Struts Action maybe) throw a specific
HTTP return code?  I need to return a 403 from a servlet if certain things
are not present in the request... is it just a matter of setting a
particular header, or is there something to throw, like an exception?

Thanks all!

--
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com




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Re: Which is best practice for stowing objects, request or session context?

2005-06-04 Thread Frank W. Zammetti

Digby has the right idea... It's not a question of which is better, 
it's a question of which is appropriate for what you are doing.


Many people do not deal in clustered environments, nor do they deal 
frankly with high scalability requirements.  I have to deal with both of 
those concerns in my daily work.  One of the things you learn in a hurry 
is that storing anything in session that doesn't really need to be there 
has a negative impact on both.  Even in a single-server environment, 
scalabilty can be adversely affected fairly quickly when session size 
isn't a concern to a developer.


My rule of thumb is to put everything in request unless I know for sure 
there is a reason to put it in sesion.  This might be a need across 
multiple pages as Digby says, or just because I know it is somewhat 
expensive to reproduce the content (i.e., maybe a complex SQL query). 
And when I do have to put anything in session, I try and store the 
smallest amount of data I possibly can to accomplish what I'm doing.


I have never had a situation where I needed application context by the 
way, not for something that deals with request servicing.  I don't know 
if it is true these days to be honest, but back when I did nothing but 
Microsoft-based development, it was a pretty well-known fact that it was 
more expensive to store things in session than in request, and even more 
expensive to store things in context than session.  Even if that isn't 
true today in the Java world, I still proceed as if it is because that 
mentailty tends to push stored data/objects down to where they should be 
in terms of lifetime and scope.


Frank

Digby wrote:
IMHO, I would suggest storing objects for the shortest time possible. If 
an object is only going to be used once, there's no point clogging up 
memory with lots of unused objects, which won't be garbage collected 
until the session is destroyed.


My rule of thumb is to use the request when it's a one-off, the session 
if it might be used by another page, and the application if it will be 
used by more than one user (which is quite rare).


Digby


Adrian Beech wrote:


Hi all,

A work colleague mentioned on Friday it would be better to place objects
(beans and the like) which had been created in a servlet into the request
context when exposing them to the JSP.  To date all the code I've written
stores beans and the like in the session context and all has appeared 
to be
fine thus far.  I understand the nature of the various contexts and 
how they

relate to the process life cycle, etc.

Can someone please shed some light on this and possibly explain the 
merits

of placing the objects in either context?  For example, what are the
pitfalls of using the request context?  Is there any material around 
which

adequately details when or when not to use the specific contexts?

Cheers.
AB




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Re: IE-Page not found problem

2005-06-06 Thread Frank W. Zammetti

Moving on to a more helpful answer...

Have you tried using something like HTTPWatch to see what's going on?  IE
seems to display that page generically for a host of different problems,
and viewing the underlying HTTP transaction might narrow things down a
bit.

Also, you could ask your users to turn off the friendly messages
option... I'm not certain, but I believe they will get you slightly more
helpful (to you) messages with that option turned off.  It's under
Tools...Internet Options... Advanced... Show Friendly HTTP Error Messages.

-- 
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

On Mon, June 6, 2005 10:22 am, Joe Plautz said:
 Simple, test with IE as well.

 sudip shrestha wrote:
 I have a struts-hibernate powered webapp running off a debian box, jdk
 1.5 and tomcat 5.5.7
 I have IE users complaining about page not found problems from time to
 time where as Firefox users never. I myselft have never encountered
 this problem as I use FirefoxThis led me to thinking that this
 might be a IE problem...Any suggestions on how to move ahead on the
 problem?

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Re: IE-Page not found problem

2005-06-06 Thread Frank W. Zammetti

Please see my previous post in this thread for some actual help
(potentially anyway).

-- 
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

On Mon, June 6, 2005 11:14 am, sudip shrestha said:
 I have no idea why you are continuing on this pathBut all I am
 looking for is suggestions on how to debug this problem with IE, if
 there is any.  I am not offerring any excuse!!  It's my work related
 work.  I have had few issues with IE in the past such as url
 redirection problem but I have managed to find the fix for those.  So,
 I was thinking maybe somebody in the users list have had some kind of
 positive experience with this in the past.  Frank's suggestion on this
 regard was constructive.  I work in a huge company...suddenly asking
 users to change the browser is not exactly the pratical solution
 either.

 On 6/6/05, Joe Plautz [EMAIL PROTECTED] wrote:
 Sorry for not including the smiley face but, dude, you're informing of a
 problem that exists within a browser that is used by the vast majority
 of web users and for some reason refused to test with it. Works on my
 box is not a valid excuse.

 Here's a link to a html validator, http://validator.w3.org/

 Here's a link that explains a lot of the known issues,
 http://www.howtocreate.co.uk/wrongWithIE/

 sudip shrestha wrote:
  Dude:  Read the email first...
  I am informing of the problem after we experienced with IE...
 
  On 6/6/05, Joe Plautz [EMAIL PROTECTED] wrote:
 
 Simple, test with IE as well.
 
 sudip shrestha wrote:
 
 I have a struts-hibernate powered webapp running off a debian box,
 jdk
 1.5 and tomcat 5.5.7
 I have IE users complaining about page not found problems from time
 to
 time where as Firefox users never. I myselft have never encountered
 this problem as I use FirefoxThis led me to thinking that this
 might be a IE problem...Any suggestions on how to move ahead on the
 problem?
 
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Re: Tomcat, SSL, IE, and .pdf downloads

2005-06-07 Thread Frank W. Zammetti

Ironically, I ran into this last week as well.

However, I was running my app on Websphere, and the cause (and solution)
was subtly different...

It is a Struts-based application.  I had the nocache RequestProcessor
setting in effect.  This caused PDF generation to fail under SSL, same as
the referenced issue.

Removing the setting resolved the issue, but I then had to create a quick
filter that would set the same cache headers the nocache setting does but
allows me to define a list of paths that they should NOT be set for.  So,
now everything in the app gets the cache headers set EXCEPT the three
paths accessed to generate PDFs, and life is good again.

The point is be sure that it's no Tomcat setting the headers... and even
if it is and you turn that off, be sure they aren't getting set anywhere
else, like Struts, or some other app code.

-- 
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

On Tue, June 7, 2005 2:46 pm, Mark Thomas said:
 This seems to be a popular subject today. Try looking at
 http://marc.theaimsgroup.com/?l=tomcat-userm=111811136603781w=2

 Mark

 Panichi, Mary-Beth wrote:
 Greetings ~

 We're having issues downloading .pdf files in SSL.  I've been all over
 the web trying to find solutions.  The issue appears to be interaction
 between Tomcat and InternetExplorer.  IE appears to be corrupting the
 pdf files.  There's an IE patch out there, but we've patched past that.
 The fix that they list, to uncheck the don't allow encrypted data to be
 cached to disk,  works, but it's a setting that for security reasons we
 don't want to leave unchecked.

 I've tried all manner of setting headers for cache-control, etc..  We're
 dynamically generating the .pdf files, and streaming them to the jsp
 page.   I've tried also saving the pdf's physically to the server and
 then getting them, but that didn't work either.

 Has anyone run into this issue?  Does anyone have a solution?  I've seen
 lots of suggestions out there, but nothing that actually works.

 Thanks!

 Mary Beth Panichi


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Re: Probably an easy answer

2005-06-10 Thread Frank W. Zammetti

If it is a class member you could conceivably use reflection to see if a 
given object/class has a member you name... if it's local though, no, 
it's a purely compile-time check.


Do you really mean declared or do you perhaps mean initialized?

Frank

Charles P. Killmer wrote:

Is there a way to, at runtime, check if a variable is declared?  I have
some code that I want to behave differently depending on whether or not
a variable has been declared.  I tried using a try catch block but it
gets caught at compile time.

Thanks
Charles

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RE: Probably an easy answer

The only other possible way I can think of, and I would have to do so
experimenting to see if/how exactly it would work, would be something
like:

try {
  Object a = b; // Where b might be declared or might not be
} catch () { // Not sure what exception would be thrown
  // Do something when b wasn't declared
}

I'm assuming there is a runtime exception to check for... that may not be
true at all... part of me suspects there isn't... that's why I'd have to
do some experimenting :)

In fact, being in a JSP this might be the best option because I'm not sure
how you could use reflection as I suggested, i.e., what object would you
inspect when the field you want to check for is a JSP variable?  I'm not
sure.

-- 
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

On Mon, June 13, 2005 8:58 am, Charles P. Killmer said:
 Thanks.  And I do mean declared.  I have a jsp that is included by a few
 other jsp's.  Some of them declare a variable and some do not.  Right
 now I have two files that are almost identical.  One expects the
 variable to be present and the other does not.  I am looking to
 consolidate these two files.

 Charles

 -Original Message-
 From: Frank W. Zammetti [mailto:[EMAIL PROTECTED]
 Sent: Friday, June 10, 2005 5:46 PM
 To: Tomcat Users List
 Subject: Re: Probably an easy answer

 If it is a class member you could conceivably use reflection to see if a
 given object/class has a member you name... if it's local though, no,
 it's a purely compile-time check.

 Do you really mean declared or do you perhaps mean initialized?

 Frank

 Charles P. Killmer wrote:
 Is there a way to, at runtime, check if a variable is declared?  I
 have some code that I want to behave differently depending on whether
 or not a variable has been declared.  I tried using a try catch block
 but it gets caught at compile time.

 Thanks
 Charles

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RE: Probably an easy answer

Yeah, I wasn't sure that would work... Seemed like it would still be a
compile error, but worth a shot.

I'm out of ideas at the moment.  I agree with what another poster said
though... seems like there must be a better way to check than whether a
variable is declared or not.  I understand the problem you are trying to
solve, I actually dealt with a similar issue with included code needing a
Javascript variable that may or may not be present, but in this case I'm
not sure of a good answer.

-- 
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

On Mon, June 13, 2005 10:19 am, Charles P. Killmer said:
 I tried the try catch block and that led me to asking this forum.  I
 tried a generic catch (Exception e)  and it resulted in a compile error.
 My suspicion is that this is not an easy thing to do.

 Any brainstorms out there?

 Charles

 -Original Message-
 From: Frank W. Zammetti [mailto:[EMAIL PROTECTED]
 Sent: Monday, June 13, 2005 8:34 AM
 To: Tomcat Users List
 Cc: Tomcat Users List
 Subject: RE: Probably an easy answer

 The only other possible way I can think of, and I would have to do so
 experimenting to see if/how exactly it would work, would be something
 like:

 try {
   Object a = b; // Where b might be declared or might not be } catch
 () { // Not sure what exception would be thrown
   // Do something when b wasn't declared }

 I'm assuming there is a runtime exception to check for... that may not
 be true at all... part of me suspects there isn't... that's why I'd have
 to do some experimenting :)

 In fact, being in a JSP this might be the best option because I'm not
 sure how you could use reflection as I suggested, i.e., what object
 would you inspect when the field you want to check for is a JSP
 variable?  I'm not sure.

 --
 Frank W. Zammetti
 Founder and Chief Software Architect
 Omnytex Technologies
 http://www.omnytex.com

 On Mon, June 13, 2005 8:58 am, Charles P. Killmer said:
 Thanks.  And I do mean declared.  I have a jsp that is included by a
 few other jsp's.  Some of them declare a variable and some do not.
 Right now I have two files that are almost identical.  One expects the

 variable to be present and the other does not.  I am looking to
 consolidate these two files.

 Charles

 -Original Message-
 From: Frank W. Zammetti [mailto:[EMAIL PROTECTED]
 Sent: Friday, June 10, 2005 5:46 PM
 To: Tomcat Users List
 Subject: Re: Probably an easy answer

 If it is a class member you could conceivably use reflection to see if

 a given object/class has a member you name... if it's local though,
 no, it's a purely compile-time check.

 Do you really mean declared or do you perhaps mean initialized?

 Frank

 Charles P. Killmer wrote:
 Is there a way to, at runtime, check if a variable is declared?  I
 have some code that I want to behave differently depending on whether

 or not a variable has been declared.  I tried using a try catch block

 but it gets caught at compile time.

 Thanks
 Charles

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 http://www.omnytex.com


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Re: Help/Examples setting up security settings

 with all this in it?  Let's walk through it...

(1) User enters http://mysite.com/admin/page1.jsp

(2) The container looks through the defined security-constraint's and
looks for one with a url-pattern element that matches the requested URL.
 In this case it finds one.

(3) So, security kicks it.  Now the login-config element is looked at
and we see that form-based authentication is in use.  So, the page named
in the form-logon-page element is displayed.  Note that if you were
using basic auth, the user would get a popup box.

(4) In either case, they enter their username and password.

(5) At this point, we get into container-specific stuff... basically,
whether it is a lookup against an LDAP directory, or against a Tomcat XML
file, or something else entirely, j_security_check (a servlet) is
responsible for this.  It looks up the user, and assuming they are found,
returns the group they are in.  Might be AdminRole in this case, might be
PlainOldUserRole, or something else.  P.S., if the user isn't found, or
their password is not correct, a 403 error is returned.,  You can name
what page to display in this case by adding to web.xml:

  error-page
error-code403/error-code
location/jsp/badLogon.jsp/location
  /error-page

(6) So, the container then has the group the authenticated user is in...
So it consults the security-role elements and finds a match.  It then
looks again at the security constraints that the URL mapped to and see if
the group the user is in is defined as having rights to that resource.

(7) Assuming the group the user is in has rights, the original request
goes through. This might be confusing... remember that the reason the
login screen was displayed was because the user requested a constrained
resource... you can think of that request as being placed on hold, in a
sense, until the user is authenticated.  Once they are, the original
request continues and the resource is returned.  Let me see if my ASCII
art is up to the challenge...


| Request for /admin/page1.jsp |

  ||
  \/

| Security intercept: login page shown |

  ||
  \/
-
| Login form submit |
-
   ||
   \/
---
| User validated and belongs to allowed group |
---
  ||
  \/
-
| Request forwarded to /admin/page1.jsp |
-

Ok, hope that gets the point across.  So, but the end of that chain, the
page1.jsp is now displayed, the user is happy :)  Note that this process
as outlined is conceptual... there could be some details in how the
container does it's thing that I got wrong... from your perspective, and
the perspective of what the user sees though, it is correct.

I think that's everything.  Hope that helps!

-- 
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

On Mon, June 13, 2005 1:55 pm, Gagnon, Joseph M  \(US SSA\) said:
 Hello,

 Does anyone have any examples of how to set up my deployment descriptor
 (web.xml in Tomcat 5.5.9) to do BASIC authentication (of any of the
 other methods, for that matter)?

 I've looked at various sources of information on the web (including some
 of Sun's sites), but have not yet found good examples (more than one
 would be great), from soup to nuts, with good explanations along the
 way, describing the various elements involved (what they do and why (or
 why not) they are needed).

 A lot of these sources provide copious amounts of information, but not
 good working examples that I can either use directly, or at least learn
 from.  Many times example chunks of code are provided, but it's not made
 clear what each element does.  Also, quite often only one example of a
 specific usage (say: FORM based authentication) is provided, but others
 are not.

 I guess the basic gripe I have is that there's a lot of information
 provided for this technology, but very little information provided that
 actually helps someone who's just learning this stuff, actually learn
 HOW to use it.

 Now there's a caveat: I'm investigating possibly using JSP for a
 work-related project.  I am looking at adding some functionality to an
 existing web application that is currently written as an ASP app.  Among
 other things, I am trying to evaluate JSP to see what advantages it may
 (or may not) provide over the existing ASP.

 At this point, I'm trying to take a small part (essentially the front
 end) of the ASP app. and JSP-icize it to see what's involved in creating
 the same (or similar) functionality.  Unfortunately I keep running into
 problems that for the most part, result from my lack of knowledge in
 this technology area.

 I do not want

Test, please ignore

Sorry for the disturbance... trying to troubleshoot a posting issue...
this will be the only such post to this list from me.  Sorry again!

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RE: [OT] Help/Examples setting up security settings

Thanks very much Chuck!  I'm glad I can help whenever I can.  I know how
overwhelming some of this stuff can be, to me as much as anyone else, and
I also know how it feels to not be able to find explanations that are easy
to understand.  If I can make that situation just a little better, I am
happy to do so. :)

-- 
Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

On Mon, June 13, 2005 3:45 pm, Caldarale, Charles R said:
 From: Frank W. Zammetti [mailto:[EMAIL PROTECTED]
 Subject: Re: Help/Examples setting up security settings

 Having just spent a couple of weeks integrating a new
 security framework into an existing app, a framework
 that works in concert with J2EE security, let me see
 if I can help... Hang on, this is going to be a long
 post!...

 Frank -

 I've been perusing this list for some time now, and I have to say that
 you provide some of the most concise and lucid explanations I've ever
 seen.  It's a pleasure to read them.  Thank you very much.

  - Chuck


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RE: Help/Examples setting up security settings

On Tue, June 14, 2005 9:26 am, Gagnon, Joseph M  \(US SSA\) said:
 Very simple stuff. However, when I try to login (by loading the
 login.jsp page), I get the following error from Tomcat:

 HTTP Status 404 - /SPID_JSP/j_security_check
 
 

 type Status report

 message /SPID_JSP/j_security_check

 description The requested resource (/SPID_JSP/j_security_check) is not
 available.

 
 
 Apache Tomcat/5.5.9

 Obviously, there are some other things that I need to do, but I don't
 know what they are. Also, I'm curious how to direct control to the
 success page once authentication passes and the login succeeds.

Hmmm... The only thing that strikes me odd is what is being requested...
Every time I've seen it, j_security_check is in the root... I wonder if
Tomcat doesn't recognize j_security_check as being a special servlet if
it isn't in the root?  Just for chuckles, move your JSPs to the root of
your webapp, that should result in /j_security_check being what the form
is submitted to, see if that solves the problem (I *think* you could make
the action of your form ../j_security_check instead of moving
everything, that should do the same thing and would be easier).  If that
doesn't work then there is probably something else specific to Tomcat that
needs to be done to enable that servlet that I am not aware of.

As for the question of directing control to the success page, this is one
of those things that is a bit confusing at first... you really don't
direct control anywhere... what should happen is the URL your users should
access *IS* the success page, assuming the succcess page is a constrained
resource... in other words, write your application with the assumption
that a user is already authenticated and that really the login page IS NOT
part of your application.  Then, when they try to access the success page,
the request will be intercepted and the login page shown.  If they enter
valid credentials, THEN the success page will be returned to them
automatically.

That part usually confuses people at first (I think it did me too for a
few minutes when I first dealt with this).  Just remember, it's an
intercept-based security mechanism... when the user tries to hit a
protected resource, the request is intercepted and they are challenged
to authenticate themselves.  Conceptually, think of the original request
as having been put on hold.  Once they authenticate, the request
continues where it left off, you have nothing special to do.

 I'm really very new at web programming, so I'm sure there are either a
 lot of stupid things I'm doing, or stuff I need to do, but am not.

No, I think you've managed to get pretty far essentially on your own... 
Good job!  :)

Frank

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Re: Help/Examples setting up security settings

 dump, except this time,
the page header shows what I expect: Get Environment Data.

First, why didn't I get presented with the login page? Isn't that what
was supposed to happen?

Second, I don't understand the dual behavior observed above. Why should
I get what happens in scenario 1? The file requested exists at the
location specified. What gives? Why does scenario 2 allow me to access
my page as I would expect to?

Obviously, I don't know diddly-squat about how this technology works and
is meant to be used. Everything I try ends up either a drop dead failure
or confuses me even more than I already was. There does not seem to be
any consistency to the behaviors I've been seeing. If someone asked me
right now whether to recommend using JSP, I'd have to say No. I can't
even get a simple test scenario to work.

I'm trying to hold off on buying any books on the subject, because I'm
not sure which ones would be the best to get (although I have some
ideas) and more importantly, because I am trying to evaluate the
technology and the feasibility (not to mention the do-ability) of
potentially converting an existing ASP application to JSP. The books
would be purchased through my department, and I don't want to have a
bunch of books bought that I may end up not using, if the decision ends
up being that we won't go the JSP route.

I realize that it's difficult for someone reading this to get the full
picture of my situation. I've tried to include all pertinent
information.

If anyone can help me out, I would sure appreciate it. (Thanks again
Frank Zammetti for the information you've provided so far.)

Thanks,
Joe Gagnon



-Original Message-
From: Frank W. Zammetti [mailto:[EMAIL PROTECTED] 
Sent: Tuesday, June 14, 2005 9:39 AM

To: Gagnon, Joseph M (US SSA)
Cc: Tomcat Users List
Subject: RE: Help/Examples setting up security settings

On Tue, June 14, 2005 9:26 am, Gagnon, Joseph M  \(US SSA\) said:


Very simple stuff. However, when I try to login (by loading the
login.jsp page), I get the following error from Tomcat:

HTTP Status 404 - /SPID_JSP/j_security_check








type Status report

message /SPID_JSP/j_security_check

description The requested resource (/SPID_JSP/j_security_check) is not
available.








Apache Tomcat/5.5.9

Obviously, there are some other things that I need to do, but I don't
know what they are. Also, I'm curious how to direct control to the
success page once authentication passes and the login succeeds.



Hmmm... The only thing that strikes me odd is what is being requested...
Every time I've seen it, j_security_check is in the root... I wonder if
Tomcat doesn't recognize j_security_check as being a special servlet
if
it isn't in the root?  Just for chuckles, move your JSPs to the root of
your webapp, that should result in /j_security_check being what the form
is submitted to, see if that solves the problem (I *think* you could
make
the action of your form ../j_security_check instead of moving
everything, that should do the same thing and would be easier).  If that
doesn't work then there is probably something else specific to Tomcat
that
needs to be done to enable that servlet that I am not aware of.

As for the question of directing control to the success page, this is
one
of those things that is a bit confusing at first... you really don't
direct control anywhere... what should happen is the URL your users
should
access *IS* the success page, assuming the succcess page is a
constrained
resource... in other words, write your application with the assumption
that a user is already authenticated and that really the login page IS
NOT
part of your application.  Then, when they try to access the success
page,
the request will be intercepted and the login page shown.  If they enter
valid credentials, THEN the success page will be returned to them
automatically.

That part usually confuses people at first (I think it did me too for a
few minutes when I first dealt with this).  Just remember, it's an
intercept-based security mechanism... when the user tries to hit a
protected resource, the request is intercepted and they are challenged
to authenticate themselves.  Conceptually, think of the original request
as having been put on hold.  Once they authenticate, the request
continues where it left off, you have nothing special to do.



I'm really very new at web programming, so I'm sure there are either a
lot of stupid things I'm doing, or stuff I need to do, but am not.



No, I think you've managed to get pretty far essentially on your own... 
Good job!  :)


Frank

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Frank W. Zammetti
Founder and Chief Software Architect
Omnytex Technologies
http://www.omnytex.com

Re: Concurrent login detection - how?

A SessionContextListener gets called when a session times out, or is 
otherwise invalidated.  This is how you do it.  I did this in an app 
some time ago... I just needed to maintain a list of who was logged in. 
   You can do something simple like I did: have a UsersList object with 
a single static HashMap in it.  In that HashMap goes User objects.  When 
the session is created, the listener is called, and you put the User 
object in it.  When the session is destroyed, you remove it.  I keyed 
the HashMap off user ID, you can do it however you like.  Just be sure 
to take concurrency into account and it works rather well.  You could do 
it to a database if your requirements make that a better choice.


Frank

Michael Mehrle wrote:
That actually goes to the heart of my question: HOW do I detect when 
their session times out? ;-)
I know the 'strategy' of doing this, but I don't know how to capture a 
timed-out session - technically. Any input would be welcome.


TIA,

Michael

- Original Message - From: David Rickard 
[EMAIL PROTECTED]

To: Tomcat Users List tomcat-user@jakarta.apache.org
Sent: Tuesday, June 14, 2005 9:53 AM
Subject: Re: Concurrent login detection - how?




Remove IDs from the List when users log out (and add a
ServletContextListener to catch people who leave the site without logging
out--remove their IDs when their sessions time out);

At 09:22 AM 6/14/2005, you wrote:

What is the best way to detect two people being logged in 
concurrently using
the same account? This is one aspect of my efforts to restrict 
fraudulent
access. Again, I don't want to use Acegi since it seems to break the 
rest of

my app. So, what's the best way to do this 'traditionally'?

Thanks!

Michael


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Re: IE-Page not found problem

I realize this is the Tomcat list, but I suspect many people here use 
Struts in developing their apps... I think it is worth noting that 
Struts provides a nocache switch for the Request Processor that does 
the same thing (setting the no cache headers).   I found this out the 
hard way about two weeks ago when I ran into this very problem, but it 
turned out to be caused by this Struts option as I was running under 
Websphere.  The point being that even if you can disable the option in 
Tomcat (and I'm not sure you can?), if you are using Struts you still 
could experience the same issue if you aren't aware the the headers 
could be set in two places.


FYI, I wound up writing a filter that lets me define paths that WILL NOT 
have the cache headers set, all others they are set for (because all but 
three paths in my app needed the headers set, the 3 were where PDFs get 
generated).  I use this in place of the Struts setting.  This filter 
will appear in my Sourceforge JavaWebParts project, in case anyone else 
might be interested.


Frank

Mark Leone wrote:


Maybe IEs implementation existed before HTTP 1.1 and before the 
no-store option was introducted, which seems to clarify the matter 
of what isn't allowed to be stored to disk, there is nothing else in 
the specififcation that mandates the user-agent or cache can not (in 
the process of serving the orginary request) store it to disk (if the 
implementation needs to).



That's a charitable way to look at it, and an interesting observation. 
However, MS explicitly justifies the behavior in reference to the 
no-cache directive (see second link below), and I believe that neither 
the HTTP 1.0 Pragma semantics nor the HTTP 1.1 Pragma and Cache-Control 
semantics support the behavior. Given, as you pointed out, that the 
no-store option in HTTP 1.1 clears it up, then I think IE's 
implementation is even more unreasonable, as there is a check-box for 
HTTP 1.1 support.


I've worked with dynamic HTML for quite a few years and can't remember 
stumbling over this problem, what is the simplest server response that 
triggers this problem in IE ?



The problem occurs when using IE over an SSL connection, when the server 
includes either cache-control: no-cache or pragma: no-cache headers, 
or both, in the response, and the user is attempting to download a file 
that is not rendered in the browser (e.g., the file is either to be 
saved to disk or launched in some app other than a browser). Note that 
IE does not manifest the problem when the no-cache directives are sent 
in the response for non-SSL connections. I believe that Tomcat sends the 
no-cache directives when serving a resource from a protected context, 
i.e. one for which a security-constraint is defined.


(Mary-Beth reported here earlier that she got IE to behave properly by 
unchecking the option Do not save encrypted pages to disk, but I tried 
this and it did not alleviate the problem. I believe Mary-Beth was 
dealing with a different issue. It's worth noting that MS does not list 
unchecking this option as a workaround in their bug report response for 
this issue.)


The Tomcat bug report on it can be found here:

http://issues.apache.org/bugzilla/show_bug.cgi?id=27122

And the IE bug report and MS response can be found here:

http://support.microsoft.com/?id=316431

The issue is especially vexing IMO because of how it manifests. IE 
actually draws the download box with the progress bar, showing the 
correct web address and even the correct mime type of the resource. Then 
instead of beginning the download it suddenly throws up a window that 
says the site is unreachable.


-Mark




Darryl


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http://www.omnytex.com


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Re: IE-Page not found problem

 Yes, it can be done with a simple valve. See earlier message in this 
 thread for details, or follow the link to the Tomcat bug database in my 
 previous message.

I missed that thread, but this is good to know.  Thanks!

Keep in mind, this is not just a problem  with pdf files. It will happen 
 when IE uses SSL to download *any*  file that is not being rendered in 
the browser, when the no-cache  directive is included in the response.

Absolutely.  Worth having this clearly stated for the archives for sure.

Frank

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Re: IE-Page not found problem