I'm a JBoss and JMX novice, but I have programmed BEA WebLogic Startup
classes implementing timers.
It looks to me like a JMX timer would allow you to program scheduled events.
As I understand it, you would do the following (assuming that you are
running in JBoss):
1. add the javax.management.timer.Timer service into jboss.conf
2. write a class that does the following
a. obtain an MBeanServer reference
b. obtain the reference to the Timer object
c. register a listener class that implements the NotificationListener
interface
d. listener class contains code executed when timer event occurs
e. this class sets the timer with the MBeanServer.invoke() method
3. it is loaded as an MBean with an MLET tag in the jboss.config file
Do I have this right?
-----Original Message-----
From: marc fleury [mailto:[EMAIL PROTECTED]]
Sent: Wednesday, February 28, 2001 8:47 AM
To: JBoss-User
Subject: RE: FW: [jBoss-User] Startup servlets when using embedded
Tomcat?
shooting from the hip...
couldn't the timer service of JMX be used for *exactly* the same task?
marc
|-----Original Message-----
|From: [EMAIL PROTECTED]
|[mailto:[EMAIL PROTECTED]]On Behalf Of Swarr, Bob
|Sent: Wednesday, February 28, 2001 11:30 AM
|To: 'JBoss-User'
|Subject: RE: FW: [jBoss-User] Startup servlets when using embedded
|Tomcat?
|
|
|Check some of the proprietary features of BEA WebLogic.
|
|WebLogic has startup and shutdown classes.
|
|These classes can be scheduled so that they run at regular intervals.
|It's a very common business requirement that you might want to perform
|certain tasks at regular intervals.
|
|Robert Swarr
|-----Original Message-----
|From: Dewayne McNair [mailto:[EMAIL PROTECTED]]
|Sent: Tuesday, February 27, 2001 11:32 PM
|To: JBoss-User
|Subject: Re: FW: [jBoss-User] Startup servlets when using embedded
|Tomcat?
|
|
|So, you don't really need a servlet, you just need JBoss to activate a
|method on an object for you when it's starting up, right? There were
|several posts over the last few days about creating MBeans that get
|activated at startup time -- sounds like exactly what you need. Create an
|MBean, register it with JBoss... should do the trick. There's nothing to
|say (I think) that it has to hang around -- it should be able to
|do its work
|and bail (I haven't used this method yet, so, if that's not right, someone
|speak up).
|
|-- Dewayne
|
|----- Original Message -----
|From: "mbiolabs" <[EMAIL PROTECTED]>
|To: "JBoss-User" <[EMAIL PROTECTED]>
|Sent: Tuesday, February 27, 2001 8:44 PM
|Subject: Re: FW: [jBoss-User] Startup servlets when using embedded Tomcat?
|
|
|> Thanks Dewayne
|>
|> I should have mentioned this earlier, I'm running JBoss 2.0 Final with
|Tomcat
|> 3.2b7 (a fairly old download, I know, but so far I haven't needed a newer
|> version), with the 1.3 jdk.
|>
|> I'll try the <load-on-startup> element, that should should work if the
|servlet
|> actually executes it's code (which sets up a cache of entity beans that
|other
|> servlets, later, through client GET and POST requests, interact with). If
|all it
|> does is load the class, it's not much use - it has to execute too. I've
|used
|> that element in a web.xml for JRun, come to think of it, I'm not sure why
|I
|> thought JBoss didn't support that functionality (it is a J2EE standard
|> after-all). Hopefully, that will do the trick. Sun does have
|this to say
|about
|> the element:
|>
|> Loading servlets at server startup may fail under certain conditions.
|The
|> J2EE server can load a servlet and call a servlet's
|> init method when the server is started, but the results are
|unpredictable.
|> Such servlets include those that are registered in
|> the web.xml file with a <load-on-startup> element.
|>
|> Hopefully JBoss does this reliably. Have you tried a startup
|servlet like
|this
|> in JBoss?
|>
|> I suppose the T3StartupDef in WebLogic is somewhat similar in concept
|(both get
|> run when the server starts up), but the servlet I have in mind
|executes on
|> startup, leaves a cache of beans behind, and bails. Those T3StartupDefs
|usually
|> listen for events continually. I've used those, they're a little messy,
|but
|> seem to work in the end. I don't think I'd use them for what I want do.
|>
|> Thanks Dewayne, I think that should work.
|>
|>
|>
|> Dewayne McNair wrote:
|>
|> > Sorry for jumping in late... I wasn't paying attention when this thread
|got
|> > started, but...
|> >
|> > Are you talking about a _servlet_ that is loaded via the
|'<load-on-startup>'
|> > element in a web.xml? Or, are you talking about an _object_ that is
|loaded
|> > on startup -- an object that implements T3StartupDef in Weblogic, for
|> > example. Or, something else?
|> >
|> > Also, just for the record, what version of JBoss & Tomcat are
|you using?
|> >
|> > -- Dewayne
|> >
|> > > Thanks David
|> > >
|> > > This is a little disappointing, as this sort of thing is a 3 line
|> > properties
|> > > file addition in other application servers (although expensive ones).
|I
|> > > will try to set this up, but if it takes longer than a day I will be
|> > forced
|> > > to un-embed Tomcat, or pay for this type of functionality.
|> > >
|> > > This must have been overlooked with the initial design. It's nice to
|have
|> > > the app server and the servlet runner working together in
|the same VM,
|but
|> > > if the functionality of the servlet runner isn't as much as it would
|be by
|> > > itself, it's not much use to serious development. I hope parsing
|> > server.xml
|> > > will clear this up.
|> > >
|> > >
|> > >
|> > >
|> > > Castro, David wrote:
|> > > >I believe you can do both - though I have not done it
|myself. I will
|not
|> > > >speak too much to what I do not know; if you are familiar
|with tomcat
|(it
|> > > >sounds like you are) then it should work as you expect.
|> > > >
|> > > >The server.xml in the binary distribution contains the interceptors
|> > > >necessary to get JNDI to function correctly, and I BELIEVE this will
|work
|> > > >even for classes deployed directly through tomcat. You will not get
|> > > >optimized classloading if you deploy directly through tomcat (unless
|you
|> > > >put
|> > > >your interfaces/shared classes in the classpath).
|> > > >
|> > > >I do not know of examples and I am guessing a bit here, so keep
|asking if
|> > > >something does not work as you expect.
|> > > >
|> > > >> -----Original Message-----
|> > > >> From: Colin Payne [mailto:[EMAIL PROTECTED]]
|> > > >> Sent: Tuesday, February 27, 2001 12:04 PM
|> > > >> To: Castro, David
|> > > >> Subject: Re: FW: [jBoss-User] Startup servlets when using embedded
|> > > >> Tomcat?
|> > > >>
|> > > >>
|> > > >> Thanks David
|> > > >>
|> > > >> Are there any simple examples yet to go along with this that
|> > > >> you know of
|> > > >> (parsing server.xml)? Does this mean that you can set up contexts
|in
|> > > >> server.xml as well as JBoss, or is it restricted to one or the
|other?
|> > > >>
|> > > >>
|> > > >> Castro, David wrote:
|> > > >> >Try downloading the new binary -
|> > > >> /newsite/bin/jboss-tomcat-2.1-beta.zip
|> > > >> >
|> > > >> >server.xml is now parsed, so I am thinking that will solve your
|> > > >> >problem...
|> > > >> >
|> > > >> >> -----Original Message-----
|> > > >> >> From: Colin Payne [mailto:[EMAIL PROTECTED]]
|> > > >> >> Sent: Tuesday, February 27, 2001 10:34 AM
|> > > >> >> To: JBoss-User
|> > > >> >> Subject: Re: [jBoss-User] Startup servlets when using
|> > > >> embedded Tomcat?
|> > > >> >>
|> > > >> >>
|> > > >> >> Hi Steve
|> > > >> >>
|> > > >> >> I should clear something up. I have successfully deployed
|> > > >> the simple
|> > > >> >> servlet examples using .war files and simple contexts, that
|> > > >> >> is not what I'm
|> > > >> >> talking about.
|> > > >> >>
|> > > >> >> Rather, I'm talking about a servlet which you can't hit
|> > > >> through a web
|> > > >> >> browser, one that is executed (and has been set up to do so,
|> > > >> >> like you would
|> > > >> >> normally do through Apache's server.xml) when the servlet
|> > > >> >> engine (and JBoss
|> > > >> >> server, in this case) starts up. I want to do this to cache
|> > > >> >> a number of
|> > > >> >> entity beans upon server startup. This is pretty standard
|> > > >> >> functionality,
|> > > >> >> WebLogic and JRun both allow you to do this, for example, as
|> > > >> >> does Tomcat
|> > > >> >> when you use server.xml (which is ignored in the Tomcat-JBoss
|> > > >> >> configuration). There is a big difference between a startup
|> > > >> >> servlet and one
|> > > >> >> that you hit through a GET or POST request.
|> > > >> >>
|> > > >> >> If I can't execute startup servlets with the Tomcat-JBoss
|> > > >> >> configuration,
|> > > >> >> then it's useless to me, I'll have to run Tomcat with Apache,
|> > > >> >> and let JBoss
|> > > >> >> run in its own virtual machine. I must have startup servlets.
|> > > >> >>
|> > > >> >> Please let me know if this is still unclear.
|> > > >> >>
|> > > >> >> JBoss-User wrote:
|> > > >> >> >> Thanks Steve
|> > > >> >> >>
|> > > >> >> >> I'm still a little unclear as to whether the servlet is
|> > > >> >> actually run
|> > > >> >> >(ie. to
|> > > >> >> >> cache some objects) or is the context just registered?
|> > > >> >> >
|> > > >> >> >Well, here it actually runs ... I hit
|> > > >> >> localhost:8080/<context name> and
|> > > >> >> >there's the pages. Is that same format failing there?
|> > > >> >> >
|> > > >> >> >S-
|> > > >> >> >
|> > > >> >> >>
|> > > >> >> >> JBoss-User wrote:
|> > > >> >> >> >> Hello
|> > > >> >> >> >>
|> > > >> >> >> >> Has anyone had any success configuring and deploying a
|> > > >> >> servlet that
|> > > >> >> >> >gets
|> > > >> >> >> >> executed upon the JBoss server startup, when using the
|> > > >> >> >> >> embedded-Tomcat/JBoss configuration?
|> > > >> >> >> >
|> > > >> >> >> >Yes, this was no problem. I put a .war file (standard
|> > > >> >> internal format)
|> > > >> >> >in
|> > > >> >> >> >the
|> > > >> >> >> >deploy directory of jBoss. It notices this at once
|and loads
|it
|> > > >> >> >(default
|> > > >> >> >> >config) and also loads it at startup.
|> > > >> >> >> >
|> > > >> >> >> >As far as configuring, my .war is called "ums.war" and
|> > > >> >> gets assigned
|> > > >> >> >the
|> > > >> >> >> >context "ums", but I am not sure if these two facts
|> > > >> are causally
|> > > >> >> >> >connected.
|> > > >> >> >> >Also, the index.html is not found when loading
|> > > >> >> localhost:8080/ums, but
|> > > >> >> >> >instead
|> > > >> >> >> >the name must be specified
|> > > >> ("localhost:8080/ums/index.html"). I am
|> > > >> >> >pretty
|> > > >> >> >> >sure that all this can be configured correctly through
|> > > >> >> JMX but have no
|> > > >> >> >> >idea
|> > > >> >> >> >how yet. :)
|> > > >> >> >> >
|> > > >> >> >> >You can make .war files easily if you set up your project
|> > > >> >> to use ant.
|> > > >> >> >See
|> > > >> >> >> >"Developing Applications With Tomcat" which is in the
|> > > >> >> docs that come
|> > > >> >> >with
|> > > >> >> >> >TomCat.
|> > > >> >> >> >
|> > > >> >> >> >HTH,
|> > > >> >> >> >
|> > > >> >> >> >S-
|> >
|> > --
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|>
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