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From "Patrick Linskey" <>
Subject Re: the pain of post processing bytecode (another beg for a simple reflection/cglib alternative like hibernate)
Date Thu, 17 May 2007 15:22:53 GMT
> Patrick also mentioned writing an IDEA plug-in (not sure if that's the right
> name) that would do the enhancement. I believe he ran into a few snags
> getting access to IntelliJ jars. This or something similar might be a good
> solution for you. Ideally we'll have Eclipse, IDEA and NetBeans plugins
> someday.

I've worked out the snags, actually. Need to figure out how to publish
it now, since it has some dependencies on IDEA jars.


On 5/17/07, Michael Dick <> wrote:
> Hi James,
> I don't know how easy this is to do with IDEA, but what I've done in Eclipse
> is to create the project via mvn eclipse:eclipse then create a run
> definition for org.apache.openjpa.enhance.PCEnhancer. With no other
> classpath tweaking it enhances the entities in the output directory and I'm
> up and running.
> Another alternative would be to use dynamic enhancement when you run in your
> IDE. In eclipse you can just add -javaagent:${} as a
> vm argument and you won't have to run the enhancer at all.
> Patrick also mentioned writing an IDEA plug-in (not sure if that's the right
> name) that would do the enhancement. I believe he ran into a few snags
> getting access to IntelliJ jars. This or something similar might be a good
> solution for you. Ideally we'll have Eclipse, IDEA and NetBeans plugins
> someday.
> Eclipse also allows user defined builders to be run in addition to the
> default java compiler. The builders can be ant scripts or java programs -
> either one should be able to enhance your entities. I have never used IDEA,
> but I suspect it includes a similar concept.
> All that being said I'm not trying to dismiss your idea of adding a cglib
> interface - I'm just sharing what has worked for me and some ideas that
> might also work for you. It's a bit specific to Eclipse, but from what I've
> heard IDEA is a very good IDE and I suspect it can do them as well.
> -Mike
> On 5/17/07, James.Strachan <> wrote:
> >
> >
> > Firstly before I start, openjpa is a great piece of software; I'm
> > particularly fond of the documentation and in particular the query
> > language
> > parts. The CSS for the site is also awesome :)
> >
> > However compared to hibernate, openjpa is still pretty painful to use from
> > an end users perspective and I don't think this should be the case; plus I
> > don't think it'll take much time to fix. While the pain is still fresh in
> > my
> > mind I thought I'd post on how much more painful openjpa is to use in a
> > project. If you're short on time, the basic idea is its that bytecode post
> > processing stuff thats to blame :). Yes I know its probably faster that
> > way
> > - its just so painful for Java programmers to work with. (And yes I know
> > one
> > day we'll all have IDE plugins that hide the bytecode stuff etc etc).
> >
> > So the first thing is having to mess with your build (ant or maven) to get
> > the post processing properly integrated. Depending on if you have
> > persistent
> > entities in your main or test area this can often trip you up a little (as
> > it did me). I don't know about folks on this list but the whole idea of
> > having to mess with my maven build gives me the jitters :). When you get
> > that far & the maven planets are aligned with openjpa, the next hurdle you
> > hit is how do you run stuff in your IDE. If like me you use IDEA and maven
> > 2, the project gets auto-created by default for all projects you work on.
> > However these don't work when you use openjpa as you hit the dreaded
> > 'cannot
> > function at all as you've not run the up front bytecode post processor you
> > dummy!' type error when trying to run stuff in your IDE.
> >
> > So you then add the maven-generated classes to the front of the classpath
> > in
> > your project. Hooray, after a day or two's work, you can now actually use
> > openjpa in your IDE and your build. YAY! The downside is that now when
> > navigating around your Java code, whenever you navigate into an entity
> > bean,
> > IDEA shows you the bytecode - not the source code as its confused since
> > the
> > bytecode generated stuff is different to the source code it knows about.
> > So
> > now you're faced with a dilemma - choose between navigating nicely around
> > your source code - or being able to actually run/debug your application. I
> > won't even get into the refactoring pain or having to continuously run
> > maven
> > builds while developing code to avoid getting code completion/compile
> > errors
> > etc. (I prefer to keep in my IDE where possible).
> >
> > Compare this whole malarkey with hibernate. You add hibernate to your pom,
> > generate your project and you're good to go. No messing with your project
> > build; no messing with some secret ninja IDE stuff to be able to actually
> > run & debug your code while still being able to actually navigate the
> > source. It just works. Now it might work in a crappy & slow way and
> > openjpa
> > might be way way more efficient and powerful and whatnot - but I'd rather
> > have a cheap car that just works than a ferrari that you can only drive on
> > a
> > tuesday if its sunny, but not too hot and refuses to even start if its
> > wet.
> >
> > FWIW I've just given up using openjpa for development; its just way too
> > painful. (I'm even hacking projects I work on so I use openjpa in the
> > maven
> > build but explicitly switch to hibernate in development mode; yeah its
> > more
> > work but at least I can use my IDE properly again).
> >
> > I'm cool with putting post processing into the build system (though that
> > should really only be an optimisation); but please can we have some
> > inefficient but usable reflection/cglib type approach so folks can easily
> > switch from hibernate to openjpa (and stay there) without pulling out our
> > hair & swearing too much - or sneaking back at the first opportunity to
> > get
> > an easy life?
> >
> > Please don't take this mail the wrong way - I truly want openjpa to be a
> > success, its a great piece of software. Its just a bit too hard to use out
> > of the box right now. I'd truly like it to be trivial to switch from
> > hibernate to openjpa and never have to go back.
> >
> > How hard is it to add a reflection/cglib type alternative to the upfront
> > bytecode generation (like hibernate does) to save us from the
> > development-time pain?
> >
> > --
> > James
> > -------
> >
> >
> > --
> > View this message in context:
> >
> > Sent from the open-jpa-dev mailing list archive at
> >
> >

Patrick Linskey
202 669 5907

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