[Lift] Re: [Lift committers] Re: Meeting
2009/4/16 David Pollak feeder.of.the.be...@gmail.com:
Taking the discussion to the main list
On Thu, Apr 16, 2009 at 10:23 AM, Jonas Bonér jo...@jonasboner.com wrote:
2009/4/16 David Pollak feeder.of.the.be...@gmail.com:
On Thu, Apr 16, 2009 at 7:08 AM, Jonas Bonér jo...@jonasboner.com
wrote:
2009/4/16 David Pollak feeder.of.the.be...@gmail.com:
It'd be optimal if you could discuss the JTA stuff in the public
forum.
In
terms of AOP, I'm really not kidding that AOP is not going to happen
in
Lift.
You don't like annotations? E.g. @Transactional etc.?
I'm not keen on annotations, but I can live with them.
I am firmly against anything that re-writes byte-code after the
compilation
phase for production code. Once the Scala-Maven plugin supports
compiler
plugins, then there's a lot of stuff that can be done at compile-time.
The AOP stuff I have done is based on dynamic proxies no bytecode munging.
OKay... I need to see some example to fully understand why a proxy needs AOP
rather than either (1) compile-time proxy generation or (2) the built-in
Java reflect proxy thingy.
You can impl AOP using many different techniques. I proposed the
simplest one (used by Spring, Guice etc.). Using a regular JDK Dynamic
Proxy (which is the 'build in Java reflect proxy thingy'). What is
your question?
So, what does AOP give us that can't be done at another phase?
AOP is not about a specific phase. It can be done at:
* compile time
* class load time
* runtime
Can be done with:
* Bytecode mods
* Generated proxy
* Dynamic proxy
* JVM-level hooks
Semantics to annotations.
Can you help out with an example?
Annotate a class with f.e.
@transactional(type=Required) class Foo { ..}
and have all methods in this class being invoked under a transaction
with Required semantics
or annotate a specific method
@transactional(type=RequiresNew) def foo { ..}
to get the same behavior for a method only
Annotations is the way most JEE devs are used to handle these things
since it is the approach both Spring, Guice, EJB 3 etc. etc. has
taken.
The stuff I have written allow using AspectJ pointcuts as well.
E.g. f.e. apply transactions to all methods in the service layer:
match('* com.biz.service.*(..)')
Or to a specific method:
match('void Store.buy(Item)')
But you could just use call-by-name:
transactional(TransactionType.Required) { // tx begin
.. // do stuff in TX
} // tx commit or rollback
But that pollutes the code, makes it harder to change, configure and
is not declarative.
Perhaps give the user options?
But you guys choose.
I am here to serve :-)
/Jonas
Thanks,
David
--
Lift, the simply functional web framework http://liftweb.net
Beginning Scala http://www.apress.com/book/view/1430219890
Follow me: http://twitter.com/dpp
Git some: http://github.com/dpp
--
Jonas Bonér | Crisp AB
http://jonasboner.com
http://crisp.se
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[Lift] Re: Object typecast to Mapper
Hi David,
thanks, this is working fine. Problem is resolved.
But dynamic binding is feature of java then why Scala don't support
this.
This is an important feature.
Thanks again
Amit Kumar Verma
On Apr 13, 10:10 pm, David Pollak feeder.of.the.be...@gmail.com
wrote:
I think it's best to use the built-in JSON creation code and keep the code
as JsCmd as long as possible.
Here's a snippet that will place the JSON for all the Users in the page.
I'm including the whole project as well:
class HelloWorld {
def json: NodeSeq = Script(jsonForAll(User))
private def jsonForAll[T : Mapper[T]](meta: MetaMapper[T]): JsCmd =
JsArray(meta.findAll.map(_.asJs) :_*)
}
If you have further questions, please update the project and mark the places
in the code where you have a question and we'll work from there.
Thanks,
David
On Mon, Apr 13, 2009 at 2:07 AM, Amit Kumar Verma cdac.a...@gmail.comwrote:
Hi David,
Thanks for ur replies, I just want to make a generic function which
will take an object of mapper and returns the json string of the same.
I have written only two function
1. This will be called by ajax call :
def getJSONString(xhtml: Group):NodeSeq = {
getJSONStringGeneric(TestGearLogin) // here 'TestGearLogin' is
a mapper object
}
2. function to make JSON string i.e
def getJSONStringGeneric(anyObject :Any):NodeSeq = {
var sJSONString = {\bindings\: [;
anyObject match {
case mm: MetaMapper[_] = // this line is giving error
mm.findAll.map(userdetails = {
var tempJSON = ;
val ret = new StringBuilder
ret.append({)
ret.append(userdetails.getSingleton.appendFieldToStrings
(userdetails))
ret.append(})
tempJSON = ret.toString();
// some manipulation for making correct JSON
tempJSON = tempJSON.replaceAll(\\{,\\{\);
tempJSON = tempJSON.replaceAll(\\},\\\});
tempJSON = tempJSON.replaceAll(=,\:\);
tempJSON = tempJSON.replaceAll(, , \,\);
tempJSON += ,;
sJSONString +=tempJSON
});
}
sJSONString = sJSONString.substring(0,sJSONString.length-1); //
for slicing the last comma
sJSONString += ]};
Text(sJSONString);
}
I changed the code as you suggested but getting the error as I posted.
Please advise.
Thanks
Amit Kumar Verma
On Apr 10, 9:46 pm, David Pollak feeder.of.the.be...@gmail.com
wrote:
I think the .asJs method on all Mapper instances should give you the
object
in JavaScript representation.
If you can post an entire file, I can work on helping you if the above
doesn't work.
On Thu, Apr 9, 2009 at 6:53 AM, Amit Kumar Verma cdac.a...@gmail.com
wrote:
copied the the same code but getting this error
type arguments [_] do not conform to trait MetaMapper's type parameter
bounds [A : net.liftweb.mapper.Mapper[A]]
TravelMerchantTest/src/main/
scala/com/vtech/travelmerchant/snippet default.scala line 142
1239284830763 85593
Actually I am trying to make the JSON object using a mapper object. My
function is this :
def getJSONStringGeneric(anyObject :Any):NodeSeq = {
//Console.println(anyObject.getClass
+anyObject.getClass);
//Console.println(anyObject.getClass.getName
+anyObject.getClass.getName);
//var objTemp = anyObject.asInstanceOf[MetaMapper
[TestGearLogin]];
var sJSONString = {\bindings\: [;
anyObject match {
case mm: MetaMapper[_] =
mm.findAll.map(
(userdetails: Mapper[_]) ={
var tempJSON = ;
val ret = new StringBuilder
ret.append({)
ret.append(userdetails.getSingleton.appendFieldToStrings
(userdetails))
ret.append(})
// ret will be like
{username=222,password=222,audit_dt=2009-04-06
00:00:00.0,login_pid=26}
tempJSON = ret.toString();
tempJSON = tempJSON.replaceAll(\\{,\\{\);
tempJSON = tempJSON.replaceAll(\\},\\\});
tempJSON = tempJSON.replaceAll(=,\:\);
tempJSON = tempJSON.replaceAll(, , \,\);
tempJSON += ,;
sJSONString +=tempJSON
}
)
}
sJSONString = sJSONString.substring(0,sJSONString.length-1); //
for slicing the last comma
sJSONString += ]};
Text(sJSONString);
}
but not getting a way of doing this. Please advise.
Thanks
Amit Kumar Verma
On Apr 9, 6:14 pm, David Pollak feeder.of.the.be...@gmail.com wrote:
Howdy,
Scala is a static language, so the class for casting must be known at
compile time.
[Lift] Road Map of Lift
Hi David, We are using the lift-scala framework for our development and thinking about it even more seriously. Can you please give some information on Roadmap of development of Lift framework. It will be more useful if it will give a brief description on areas on which framework is working on. Thanks Amit Kumar Verma --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: Liftweb without Maven?
On Fri, Apr 17, 2009 at 10:21 AM, Alexander Kellett lypa...@gmail.comwrote: hey sean, i hope you're open to other possibilities than buildr/raven :) i myself have no real interest in messing with maven after my terrible experiences from when i was working on java code full time.. i just verified that it takes just a few minutes to install sbt and get a running lift app :) you can find the things needed in Marks Harrah's reply to this thread and sbt can be found at http://code.google.com/p/simple-build-tool/ I'm also not very keen on using maven for my builds but I think it's fine as a black box tool for generating artifacts. Recently, we've moved all our Ant builds to Gradle which has been a (mostly) pleasant experience. It has dependency management (and can use maven repos) but you use a Groovy DSL to specify your build. There's a patch to make Gradle work with scala apps (haven'tried it), but I was wondering if anybody has used it for Scala or even Lift? /Jeppe --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: Liftweb without Maven?
Well, maybe the archetype code could be generalized and go into sbt. We can continue discussing that on the sbt mailing list if you are interested. The remaining part is just dependency declarations for the hello-lift example. Thanks, Mark On Thursday 16 April 2009, Alexander Kellett wrote: excellent, thanks for finishing this off mark! is it possible this might get into a later sbt release or does this belong somewhere in the lift source tree? thank you! Alex On Thu, Apr 16, 2009 at 7:11 PM, Mark Harrah dmhar...@gmail.com wrote: Hi, Thanks for putting effort into this. The inline dependency declarations replace the pom.xml, so it isn't needed. You can also declare the archetype as a dependency and extract and process it. I have attached a project definition that does not require downloading the zip manually or processing with sed (it does require sbt, of course). Put it in 'project/build/src' directory in your new project directory. Then do: $ sbt bootstrap jetty-run (fill in the name and other info when prompted) Thanks again, -Mark On 4/16/09, Alexander Kellett lypa...@gmail.com wrote: attached a replacement for the sbt script provided, with inline comments for getting it to work. barely tested and trivial. not yet verified that this works without a preexisting maven install. will automate more at weekend. will look into getting the blocking-on-page-load modification into sbt/lift somehow also given that it has its own continuous compile system. On Thu, Apr 16, 2009 at 3:57 PM, David Pollak feeder.of.the.be...@gmail.com wrote: On Wed, Apr 15, 2009 at 9:37 AM, Alexander Kellett lypa...@gmail.com wrote: On Wed, Apr 15, 2009 at 5:26 PM, David Pollak feeder.of.the.be...@gmail.com wrote: While we are a community that welcomes newbies and tries to work with as many different people and with as many different styles as possible, there are things that we've collectively learned. We've found that Maven is preferable for our style of development. If you want to use Ant, there's nothing stopping you and we'd welcome some Ant scripts for building Lift, but we're not going to stop what we're doing and write one for you just because you demand that we do so. Please go back and write the Ant scripts yourself and contribute to the community rather than being rude to us because we don't do things the way you want. That will demonstrate that you are willing to contribute in rather than demand and insult when your demands are not met. many people are scared by maven. myself included after my previous fun with getting lift working. is there a way to get a self contained hello world zip up on github if it is not already there? afaiu maven also allows for local caches, could that that be placed in the zip, or is it simply too big? i think that might scare people much less than pasting the very opaque four liner which asks questions i do not know the answer to :) I am all in favor of an Ant build script or an SBT-based build script. Both would be great contributions. I do not have time for them, but anyone out there who has skills with Ant and/or SBT, I'll buy you a beer or two if you spend a couple of hours putting together examples. My rant is against the attitude that somehow the Lift community should instantly change its priorities because one person has a different perspective on things. We are not waiters in a restaurant. We are not serving peoples whims. We are a collaborative community. Anybody who treats the folks in this community as wait-staff fundamentally misunderstands the ethos of the Lift community. The Lift community is a place that I like being because almost everybody is willing to roll up their sleeves and help. Marius, Derek, Tyler, Charles, Jorge, Tim, etc. roll up their sleeves and help all comers. Each of these guys can be making more money and/or spending time with their friends and family rather than helping newbies, but when they came to the community, they were newbies and I helped them and they have perpetuated that spirit. Newbies help us by asking questions, by learning Lift, by making suggestions, by contributing code, and ultimately by helping other newbies. We welcome different perspectives, but we do not welcome insulting attitudes. Had the conversation gone more along the lines of any chance you'll change your priorities to support Ant? Not for 1.1, but perhaps you can help. I can write Ant Scripts, but I need some guidance about the dependencies... The poster would have gotten what he wanted and the whole Lift community would have benefited. So, yes, I am in favor of lots of different build options. Are committers, we have limited time and will officially support Maven. If someone else comes along and demonstrates Ant, SBT, etc.
[Lift] Re: Road Map of Lift
1.1 thread: http://groups.google.com/group/liftweb/browse_thread/thread/aca84784b81a6a2c/5539edffc1c874d1?lnk=gstq=1.1#5539edffc1c874d1 On Apr 17, 5:27 am, Amit Kumar Verma cdac.a...@gmail.com wrote: Hi David, We are using the lift-scala framework for our development and thinking about it even more seriously. Can you please give some information on Roadmap of development of Lift framework. It will be more useful if it will give a brief description on areas on which framework is working on. Thanks Amit Kumar Verma --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: Road Map of Lift
On Fri, Apr 17, 2009 at 6:05 AM, Timothy Perrett timo...@getintheloop.euwrote: Just in addition to this - Lift is very community driven, if there is something you really believe should make it into Lift core then we'll gladly listen to people's input and discuss it openly. That's exactly right. We strive to be as transparent as possible with Lift development. Tyler pointed you to the 1.1 thread. We respond to community need as well as the needs that we each have for the projects that we're working on. I place a priority on features (and defects) related to public and/or reference Lift implementations. I place a very very high priority on fixing defects for production Lift sites. Are there features or needs that you have for your project? Cheers, Tim On 17/04/2009 13:48, TylerWeir tyler.w...@gmail.com wrote: 1.1 thread: http://groups.google.com/group/liftweb/browse_thread/thread/aca84784b81a6a2c/5 539edffc1c874d1?lnk=gstq=1.1#5539edffc1c874d1 On Apr 17, 5:27 am, Amit Kumar Verma cdac.a...@gmail.com wrote: Hi David, We are using the lift-scala framework for our development and thinking about it even more seriously. Can you please give some information on Roadmap of development of Lift framework. It will be more useful if it will give a brief description on areas on which framework is working on. Thanks Amit Kumar Verma -- Lift, the simply functional web framework http://liftweb.net Beginning Scala http://www.apress.com/book/view/1430219890 Follow me: http://twitter.com/dpp Git some: http://github.com/dpp --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: Object typecast to Mapper
On Fri, Apr 17, 2009 at 2:00 AM, Amit Kumar Verma cdac.a...@gmail.comwrote:
Hi David,
thanks, this is working fine. Problem is resolved.
But dynamic binding is feature of java then why Scala don't support
this.
I'm sorry, I don't understand what dynamic binding is. Scala supports
casting just like Java.
This is an important feature.
Thanks again
Amit Kumar Verma
On Apr 13, 10:10 pm, David Pollak feeder.of.the.be...@gmail.com
wrote:
I think it's best to use the built-in JSON creation code and keep the
code
as JsCmd as long as possible.
Here's a snippet that will place the JSON for all the Users in the page.
I'm including the whole project as well:
class HelloWorld {
def json: NodeSeq = Script(jsonForAll(User))
private def jsonForAll[T : Mapper[T]](meta: MetaMapper[T]): JsCmd =
JsArray(meta.findAll.map(_.asJs) :_*)
}
If you have further questions, please update the project and mark the
places
in the code where you have a question and we'll work from there.
Thanks,
David
On Mon, Apr 13, 2009 at 2:07 AM, Amit Kumar Verma cdac.a...@gmail.com
wrote:
Hi David,
Thanks for ur replies, I just want to make a generic function which
will take an object of mapper and returns the json string of the same.
I have written only two function
1. This will be called by ajax call :
def getJSONString(xhtml: Group):NodeSeq = {
getJSONStringGeneric(TestGearLogin) // here 'TestGearLogin' is
a mapper object
}
2. function to make JSON string i.e
def getJSONStringGeneric(anyObject :Any):NodeSeq = {
var sJSONString = {\bindings\: [;
anyObject match {
case mm: MetaMapper[_] = // this line is giving error
mm.findAll.map(userdetails = {
var tempJSON = ;
val ret = new StringBuilder
ret.append({)
ret.append(userdetails.getSingleton.appendFieldToStrings
(userdetails))
ret.append(})
tempJSON = ret.toString();
// some manipulation for making correct JSON
tempJSON = tempJSON.replaceAll(\\{,\\{\);
tempJSON = tempJSON.replaceAll(\\},\\\});
tempJSON = tempJSON.replaceAll(=,\:\);
tempJSON = tempJSON.replaceAll(, , \,\);
tempJSON += ,;
sJSONString +=tempJSON
});
}
sJSONString = sJSONString.substring(0,sJSONString.length-1); //
for slicing the last comma
sJSONString += ]};
Text(sJSONString);
}
I changed the code as you suggested but getting the error as I posted.
Please advise.
Thanks
Amit Kumar Verma
On Apr 10, 9:46 pm, David Pollak feeder.of.the.be...@gmail.com
wrote:
I think the .asJs method on all Mapper instances should give you the
object
in JavaScript representation.
If you can post an entire file, I can work on helping you if the
above
doesn't work.
On Thu, Apr 9, 2009 at 6:53 AM, Amit Kumar Verma
cdac.a...@gmail.com
wrote:
copied the the same code but getting this error
type arguments [_] do not conform to trait MetaMapper's type
parameter
bounds [A : net.liftweb.mapper.Mapper[A]]
TravelMerchantTest/src/main/
scala/com/vtech/travelmerchant/snippet default.scala line 142
1239284830763 85593
Actually I am trying to make the JSON object using a mapper object.
My
function is this :
def getJSONStringGeneric(anyObject :Any):NodeSeq = {
//Console.println(anyObject.getClass
+anyObject.getClass);
//Console.println(anyObject.getClass.getName
+anyObject.getClass.getName);
//var objTemp = anyObject.asInstanceOf[MetaMapper
[TestGearLogin]];
var sJSONString = {\bindings\: [;
anyObject match {
case mm: MetaMapper[_] =
mm.findAll.map(
(userdetails: Mapper[_]) ={
var tempJSON = ;
val ret = new StringBuilder
ret.append({)
ret.append(userdetails.getSingleton.appendFieldToStrings
(userdetails))
ret.append(})
// ret will be like
{username=222,password=222,audit_dt=2009-04-06
00:00:00.0,login_pid=26}
tempJSON = ret.toString();
tempJSON = tempJSON.replaceAll(\\{,\\{\);
tempJSON = tempJSON.replaceAll(\\},\\\});
tempJSON = tempJSON.replaceAll(=,\:\);
tempJSON = tempJSON.replaceAll(, , \,\);
tempJSON += ,;
sJSONString +=tempJSON
}
)
}
sJSONString = sJSONString.substring(0,sJSONString.length-1);
//
for slicing the last
[Lift] How do you debug snippet code
Are there any debugging tools or techniques for stepping through snippet code? I would be interested in hearing from anyone on this subject. Glenn Silverman --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: [Lift committers] Re: Meeting
I'm currently giving AOP a try
herehttp://github.com/mighdoll/aspecting/tree/master(not in lift).
I was looking for a cleaner way to create objects with
observable properties. I like that an aspect allows for observable objects
that are idiomatic to use and write, and don't require any extra
boilerplate.
The scala class needs only to add the marker trait Observable.
class Model extends Observable {
var prop:String = _
}
Modifications to the instance will then trigger the aspect, notifying
an observer.
val model = new Model()
m.prop = whee
Run that and the test observer sees the change and prints:
change observed example.mo...@6abf2d5e= prop:whee
I'm getting more tempted to use aspectJ because it enables such a
simple and idiomatic
approach to writing model objects that are:
* Concise to write
* Use the normal idioms for working with mutable scala objects.
* Compatible with java libraries, including JPA...
The sources are in src.
To try it yourself, use this script which runs mvn.
./tryMe
On Fri, Apr 17, 2009 at 4:26 AM, Josh Suereth joshua.suer...@gmail.comwrote:
You can impl AOP using many different techniques. I proposed the
simplest one (used by Spring, Guice etc.). Using a regular JDK Dynamic
Proxy (which is the 'build in Java reflect proxy thingy'). What is
your question?
So, what does AOP give us that can't be done at another phase?
AOP is not about a specific phase. It can be done at:
* compile time
* class load time
* runtime
Can be done with:
* Bytecode mods
* Generated proxy
* Dynamic proxy
* JVM-level hooks
Semantics to annotations.
Can you help out with an example?
Annotate a class with f.e.
@transactional(type=Required) class Foo { ..}
and have all methods in this class being invoked under a transaction
with Required semantics
or annotate a specific method
@transactional(type=RequiresNew) def foo { ..}
to get the same behavior for a method only
Annotations is the way most JEE devs are used to handle these things
since it is the approach both Spring, Guice, EJB 3 etc. etc. has
taken.
I use this all the time in java, because there is no other good option
for transactions in java. It's basically the best method. However I don't
believe this is the case in Scala, and I'd rather think through the options
and determine the best one.
The stuff I have written allow using AspectJ pointcuts as well.
E.g. f.e. apply transactions to all methods in the service layer:
match('* com.biz.service.*(..)')
Or to a specific method:
match('void Store.buy(Item)')
Point-cuts after-the fact seem a decent use of transactions. This is under
the following assumptions:
1) Your code will be used in more than one configuration type
2) Your transaction granularity is determined by the configuration of your
module, not by the module itself.
Regarding 2, I think all-to-often real world problems begin to break this
assumption, making internal business logic and external transaction
configuration dependent on each other.
But you could just use call-by-name:
transactional(TransactionType.Required) { // tx begin
.. // do stuff in TX
} // tx commit or rollback
But that pollutes the code, makes it harder to change, configure and
is not declarative.
Perhaps give the user options?
How is it not declarative? I agree that Aspects really do give you better
configuration abilities for code, however I'm not sure transactions are
ideally suited for AOP. I think Java is not ideally suited for
transactional code, so we use AOP.
I'd love to hear your response! This is something I've been mulling
through recently, and I'm still on the fence for Transactions should be
done using AOP on the JVM
-Josh
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[Lift] Re: [Lift committers] Re: Meeting
Lee,
The reason that Lift has the richer MappedField and Field objects in Mapper
and Record is to programmatically add this kind of functionality to fields.
No, it's not PoJos, but it's as syntactically clean and a lot easier to
understand/debug.
Thanks,
David
On Fri, Apr 17, 2009 at 9:47 AM, Lee Mighdoll leemighd...@gmail.com wrote:
I'm currently giving AOP a try
herehttp://github.com/mighdoll/aspecting/tree/master(not in lift). I was
looking for a cleaner way to create objects with
observable properties. I like that an aspect allows for observable objects
that are idiomatic to use and write, and don't require any extra
boilerplate.
The scala class needs only to add the marker trait Observable.
class Model extends Observable {
var prop:String = _
}
Modifications to the instance will then trigger the aspect, notifying an
observer.
val model = new Model()
m.prop = whee
Run that and the test observer sees the change and prints:
change observed example.mo...@6abf2d5e= prop:whee
I'm getting more tempted to use aspectJ because it enables such a simple and
idiomatic
approach to writing model objects that are:
* Concise to write
* Use the normal idioms for working with mutable scala objects.
* Compatible with java libraries, including JPA...
The sources are in src.
To try it yourself, use this script which runs mvn.
./tryMe
On Fri, Apr 17, 2009 at 4:26 AM, Josh Suereth joshua.suer...@gmail.comwrote:
You can impl AOP using many different techniques. I proposed the
simplest one (used by Spring, Guice etc.). Using a regular JDK Dynamic
Proxy (which is the 'build in Java reflect proxy thingy'). What is
your question?
So, what does AOP give us that can't be done at another phase?
AOP is not about a specific phase. It can be done at:
* compile time
* class load time
* runtime
Can be done with:
* Bytecode mods
* Generated proxy
* Dynamic proxy
* JVM-level hooks
Semantics to annotations.
Can you help out with an example?
Annotate a class with f.e.
@transactional(type=Required) class Foo { ..}
and have all methods in this class being invoked under a transaction
with Required semantics
or annotate a specific method
@transactional(type=RequiresNew) def foo { ..}
to get the same behavior for a method only
Annotations is the way most JEE devs are used to handle these things
since it is the approach both Spring, Guice, EJB 3 etc. etc. has
taken.
I use this all the time in java, because there is no other good option
for transactions in java. It's basically the best method. However I don't
believe this is the case in Scala, and I'd rather think through the options
and determine the best one.
The stuff I have written allow using AspectJ pointcuts as well.
E.g. f.e. apply transactions to all methods in the service layer:
match('* com.biz.service.*(..)')
Or to a specific method:
match('void Store.buy(Item)')
Point-cuts after-the fact seem a decent use of transactions. This is
under the following assumptions:
1) Your code will be used in more than one configuration type
2) Your transaction granularity is determined by the configuration of your
module, not by the module itself.
Regarding 2, I think all-to-often real world problems begin to break this
assumption, making internal business logic and external transaction
configuration dependent on each other.
But you could just use call-by-name:
transactional(TransactionType.Required) { // tx begin
.. // do stuff in TX
} // tx commit or rollback
But that pollutes the code, makes it harder to change, configure and
is not declarative.
Perhaps give the user options?
How is it not declarative? I agree that Aspects really do give you better
configuration abilities for code, however I'm not sure transactions are
ideally suited for AOP. I think Java is not ideally suited for
transactional code, so we use AOP.
I'd love to hear your response! This is something I've been mulling
through recently, and I'm still on the fence for Transactions should be
done using AOP on the JVM
-Josh
--
Lift, the simply functional web framework http://liftweb.net
Beginning Scala http://www.apress.com/book/view/1430219890
Follow me: http://twitter.com/dpp
Git some: http://github.com/dpp
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[Lift] getting mvn jetty:run to reload changes to snippets
Hello Lifters! BTW apologies in advance if this is an obvious newbie question - I did a fair bit of searching on the list and saw JavaRebel discussions etc. I've been taking my first baby steps with Scala/Lift (this Scala/Lift malarkey is starting to grow on me) so I followed the getting started guide. My first surprise (after using Rails/JSP etc) was hitting reload on a browser after changing a snippet doesn't reload the snippet code - you've gotta stop/restart mvn jetty:run. (Though changing the template does). I just wondered if someone had figured out the ninja to get the jetty:run plugin to auto-detect snippet changes? This could well be a tooling issue (e.g. when using eclipse with its incremental compiling generating new class files might solve the problem) - I'm using IDEA currently. I did wonder if we could come up with a way to configure the jetty:run plugin to do the right thing though irrespective of your IDE; using the scala incremental compiler maybe? I tried adding a jetty custom scan target to the pom... plugin groupIdorg.mortbay.jetty/groupId artifactIdmaven-jetty-plugin/artifactId configuration contextPath//contextPath scanIntervalSeconds1/scanIntervalSeconds scanTargetPatterns scanTargetPattern directorysrc/main/scala/directory includes include**/*.scala/include /includes /scanTargetPattern /scanTargetPatterns /configuration /plugin which forces a restart fine - but it doesn't know to recompile the Scala code. So I'm wondering if we setup the scala compiler to auto build the code to a classes directory that the jetty plugin can then auto-detect and restart the web app? I just wondered if others had hit this issue come up with an elegant solution; to force incremental compilation of the Scala class files - or maybe I should just switch to eclipse? -- James --- http://macstrac.blogspot.com/ Open Source Integration http://fusesource.com/ --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: getting mvn jetty:run to reload changes to snippets
Switch to the one and only great IDE: Eclipse ;-)But be sure to use the latest Scala IDE for Eclipse (2.7.4 RC1 or later). Then you will have lots of fun! 2009/4/17 James Strachan james.strac...@gmail.com Hello Lifters! BTW apologies in advance if this is an obvious newbie question - I did a fair bit of searching on the list and saw JavaRebel discussions etc. I've been taking my first baby steps with Scala/Lift (this Scala/Lift malarkey is starting to grow on me) so I followed the getting started guide. My first surprise (after using Rails/JSP etc) was hitting reload on a browser after changing a snippet doesn't reload the snippet code - you've gotta stop/restart mvn jetty:run. (Though changing the template does). I just wondered if someone had figured out the ninja to get the jetty:run plugin to auto-detect snippet changes? This could well be a tooling issue (e.g. when using eclipse with its incremental compiling generating new class files might solve the problem) - I'm using IDEA currently. I did wonder if we could come up with a way to configure the jetty:run plugin to do the right thing though irrespective of your IDE; using the scala incremental compiler maybe? I tried adding a jetty custom scan target to the pom... plugin groupIdorg.mortbay.jetty/groupId artifactIdmaven-jetty-plugin/artifactId configuration contextPath//contextPath scanIntervalSeconds1/scanIntervalSeconds scanTargetPatterns scanTargetPattern directorysrc/main/scala/directory includes include**/*.scala/include /includes /scanTargetPattern /scanTargetPatterns /configuration /plugin which forces a restart fine - but it doesn't know to recompile the Scala code. So I'm wondering if we setup the scala compiler to auto build the code to a classes directory that the jetty plugin can then auto-detect and restart the web app? I just wondered if others had hit this issue come up with an elegant solution; to force incremental compilation of the Scala class files - or maybe I should just switch to eclipse? -- James --- http://macstrac.blogspot.com/ Open Source Integration http://fusesource.com/ -- Heiko Seeberger www.heikoseeberger.name OSGi on Scala --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: Lift works on Google App Engine (within the confines of what's possible)
On Fri, Apr 17, 2009 at 4:20 PM, Timothy Perrett timo...@getintheloop.euwrote: I just can't for the life of me figure out why anyone would want to put a Java/Scala app on GAE. The answer to this my good fellow, is simple: Marketing. D'oh! I'm such a dolt... I missed that one. Cheers, Tim -- Lift, the simply functional web framework http://liftweb.net Beginning Scala http://www.apress.com/book/view/1430219890 Follow me: http://twitter.com/dpp Git some: http://github.com/dpp --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: Lift works on Google App Engine (within the confines of what's possible)
On Fri, Apr 17, 2009 at 5:57 PM, David Pollak feeder.of.the.be...@gmail.com wrote: Folks, I've just committed a version of Lift (including the Lift Example) that runs on the Google App Engine. You can see the running demo at: http://liftdemo.appspot.com/ What's missing: - Mapper and Mapper-related stuff. You can use JPA. - Comet. GAE's lack of thread or message queue support is a huge limitation. - Actor-based session-shutdown notification is disabled on GAE. - There's no session affinity guarantee, so there may be problems with migrating sessions (I'll be working with the Google folks on this issue) Okay... so you can build apps on GAE... I have to wonder... who would want to? GAE gives you a highly scalable platform to build CRUD apps. Without a back-end messaging infrastructure, long running processes, threads, inter-session messaging, etc. there's not much in the way of exciting apps to build. Here are a list of apps that could not be built with GAE: - Twitter (requires a message bus and back-ground processing) - Facebook (has many of Twitter's requirements) - GoogleTalk - A travel site (the 30 second request duration means that looking stuff up on a back end service is not possible) - A multi-player game MySQL Game http://mysqlgame.appspot.com/ is actually pretty good multiplayer game on GAE. Here's the description if you never played: --- Are you tired of browser-based games that are thinly veiled interfaces for databases? Finally, there's a game that just *is* a database! THRILL as you insert your very own row in the rows table! With careful selection of SQL queries, you will soon have three or even four-digit numbers in some of the fields in your row! Other queries may allow you to use those numbers to subtract from rows entered by other players -- all while pushing the numbers in your own row even higher! As you master the game, you may find that you have inserted not just one row into the game, but several! --- Anyway, I wouldn't discount GAE. It's certainly not as cool as lift's comet support, but perhaps in the future you can make that happen. It does appear to have different goals than lift, but again, perhaps in the future they will be more aligned. --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] StatefulSnippet Beginner
I'm trying to play around with the StatefulSnippets and can't get it
to hold state. This is what I have for a test:
class Products {
object productVar extends RequestVar(new Product())
def selectedProduct = productVar.is
def search(xhtml: Group): NodeSeq = {
var query = ;
def processSearch() = {
// hard code id for now
val product = Model.createNamedQuery[Product](findProductById,
(id - 1L)).getSingleResult()
Log.info(processSearch: + product.id.toString) // prints 1
productVar(product)
Log.info(post processSearch: + product.id.toString) //
prints 1
S.redirectTo(select.html)
}
val plAttrs = List((size, 40), (maxlength, 80), (style,
width: 98%))
bind(f, xhtml,
query - SHtml.text(query, query = _),
submit - SHtml.submit(Search, processSearch)
)
}
def selectedQuery(xhtml: NodeSeq): NodeSeq = {
Log.info(selectedProduct: + selectedProduct.id.toString) //
HELP!: prints 0
Text(selectedProduct.name(en_US) match { case Some(a) = a.name
case None = No Product Found})
}
}
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[Lift] Re: StatefulSnippet Beginner
I guess it would help to mention that lift:Products.search / is on
index.html and lift:Products.selectedQuery / is on select.html.
On Apr 17, 9:45 pm, bradford fingerm...@gmail.com wrote:
I'm trying to play around with the StatefulSnippets and can't get it
to hold state. This is what I have for a test:
class Products {
object productVar extends RequestVar(new Product())
def selectedProduct = productVar.is
def search(xhtml: Group): NodeSeq = {
var query = ;
def processSearch() = {
// hard code id for now
val product = Model.createNamedQuery[Product](findProductById,
(id - 1L)).getSingleResult()
Log.info(processSearch: + product.id.toString) // prints 1
productVar(product)
Log.info(post processSearch: + product.id.toString) //
prints 1
S.redirectTo(select.html)
}
val plAttrs = List((size, 40), (maxlength, 80), (style,
width: 98%))
bind(f, xhtml,
query - SHtml.text(query, query = _),
submit - SHtml.submit(Search, processSearch)
)
}
def selectedQuery(xhtml: NodeSeq): NodeSeq = {
Log.info(selectedProduct: + selectedProduct.id.toString) //
HELP!: prints 0
Text(selectedProduct.name(en_US) match { case Some(a) = a.name
case None = No Product Found})
}
}
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[Lift] Re: Welcome Atsuhiko Yamanaka to the Lift Committers
Welcome,welcome,welcome ! On Apr 18, 1:42 am, David Pollak feeder.of.the.be...@gmail.com wrote: Folks, I am pleased at announce that Atsuhiko Yamanaka has joined the Lift committers. He did some great Google App Engine work with Lift and has been making other enhancements to the Lift code base. Now he can roll his changes in at will. Welcome Yamanaka-san. Thanks, David -- Lift, the simply functional web frameworkhttp://liftweb.net Beginning Scalahttp://www.apress.com/book/view/1430219890 Follow me:http://twitter.com/dpp Git some:http://github.com/dpp --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
[Lift] Re: Lift works on Google App Engine (within the confines of what's possible)
I'm very skeptic and reluctant to GAE right now with all due respect for Google.I'm used to quite large apps requiring a high degree of control, DB close to the app and tunings for the app, dedicated HW, etc. Yeah I know Google promises lots of these things I just can't see how they can provide HW control for potentially millions of applications deployed ... regardless how much money they have. Might be good though for trivial small web sites where people just wants to see it online ... Br's, Marius On Apr 18, 12:57 am, David Pollak feeder.of.the.be...@gmail.com wrote: Folks, I've just committed a version of Lift (including the Lift Example) that runs on the Google App Engine. You can see the running demo at:http://liftdemo.appspot.com/ What's missing: - Mapper and Mapper-related stuff. You can use JPA. - Comet. GAE's lack of thread or message queue support is a huge limitation. - Actor-based session-shutdown notification is disabled on GAE. - There's no session affinity guarantee, so there may be problems with migrating sessions (I'll be working with the Google folks on this issue) Okay... so you can build apps on GAE... I have to wonder... who would want to? GAE gives you a highly scalable platform to build CRUD apps. Without a back-end messaging infrastructure, long running processes, threads, inter-session messaging, etc. there's not much in the way of exciting apps to build. Here are a list of apps that could not be built with GAE: - Twitter (requires a message bus and back-ground processing) - Facebook (has many of Twitter's requirements) - GoogleTalk - A travel site (the 30 second request duration means that looking stuff up on a back end service is not possible) - A multi-player game So... on a $100/mo box from CalPop, I can run a service that will scale to 20M requests per day. If I'm doing 20M requests per day, I've got a business where I want more control over my infrastructure than GAE gives me. That might be Amazon EC2 where I can power-up and down boxes at will. There are also a number of different scalable storage solutions on Amazon. I just can't for the life of me figure out why anyone would want to put a Java/Scala app on GAE. Thanks, David -- Lift, the simply functional web frameworkhttp://liftweb.net Beginning Scalahttp://www.apress.com/book/view/1430219890 Follow me:http://twitter.com/dpp Git some:http://github.com/dpp --~--~-~--~~~---~--~~ You received this message because you are subscribed to the Google Groups Lift group. To post to this group, send email to liftweb@googlegroups.com To unsubscribe from this group, send email to liftweb+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/liftweb?hl=en -~--~~~~--~~--~--~---
