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From "Shiva Kumar H R" <shiv...@gmail.com>
Subject Re: [Discuss] Model for deployment plans in GEP - Move from EMF to XMLBeans or JAXB?
Date Tue, 04 Mar 2008 08:41:15 GMT
There have been further discussions on this in IRC and in JIRA. As
recommended in
http://mail-archives.apache.org/mod_mbox/geronimo-dev/200802.mbox/%3c5da94e5a0802212321m4b282128q89add861e150c64f@mail.gmail.com%3e
I am summarizing those discussions below:
(Tim, DJencks, DBlevins & Yun Feng - Please correct if am wrong)

1) JAXB/XMLBeans/DConfigBeans:
a) On a further discussion about XMLBeans and JAXB, we saw that writing
deployment code might turn out be much easier by using JAXB rather than
XMLBeans.

b) On a discussion about whether GEP should ideally be using JSR-88
DConfigBeans, we wondered if JSR-88 DConfigBeans are a dead idea & should be
left alone, because No One other than Geronimo even thinks about trying to
implement them.

So we concluded that it is worth experimenting with JAXB.

2) Hints from OpenEJB about using JAXB:
a) On a discussion about how OpenEJB uses JAXB, it seems schemas are
compiled only once (instead of compiling during every build as is currently
done both in Geronimo and GEP) and checked in to the source stream.
I too don't see any point in compiling G schemas during every build of GEP,
and the one time compilation & check in approach of OpenEJB looks ideal to
me for GEP also. This would lead to significant savings in build time.
Please point out if I am missing something.

b) It seems that the real beauty (& ease of use) of JAXB comes from the
ability to customize JAXB generated classes (like (i) adding interfaces,
(ii) removing all their wrappers for simple types like string, int, boolean
etc, (iii) using Maps instead of Lists for auto indexing things that can be
keyed, etc). OpenEJB uses those customizations. To keep the Customized JAXB
classes and Schema in sync, OpenEJB has unit tests that read in xml
documents, write them out again, then compare the results. A similar
approach could be used in GEP also.

3) Handling multiple schema versions
I guess JAXB could help us better with multiple version of schemas. (I mean
a single set of JAXB classes being able to read/write say geronimo-web.xmlin
v1.1, v2.0, v2.0.1 etc). We need to explore this more.

Tim, Yun Feng and myself are looking at completing this refactoring at the
earliest so that we could then focus on other JIRAs/features & release GEP
2.1. Yun Feng already has a patch that has ported good amount of GEP onto
JAXB and I am looking at committing it tomorrow.

If you forsee any concerns with the approaches above, kindly reply.

-- 
Thanks,
Shiva

On Tue, Feb 12, 2008 at 2:16 PM, Shiva Kumar H R <shivahr@gmail.com> wrote:

> Please see 11-Feb IRC chat btw djencks, shivahr & mcconne
> http://servlet.uwyn.com/drone/log/bevinbot/geronimo/20080211 for further
> discussions on this.
>
> As recommended by DJencks we will experiment using JAXB in GEP 2.1.
>
> --
> Thanks,
> Shiva
>
>
> On Feb 11, 2008 9:22 PM, David Jencks <david_jencks@yahoo.com> wrote:
>
> >
> > On Feb 11, 2008, at 7:16 AM, Shiva Kumar H R wrote:
> >
> > I went through following tutorials of JAXB & XMLBeans:
> >   a) Java Architecture for XML Binding (JAXB)
> >   http://java.sun.com/developer/technicalArticles/WebServices/jaxb/
> >   b) Tutorial: First Steps with XMLBeans
> >   http://xmlbeans.apache.org/documentation/tutorial_getstarted.html
> >
> > Also searched for comparisons btw them. Latest one I could find is the
> > following blog from Jan'2005: http://technology.amis.nl/blog/?p=321
> >
> > I am yet to see the value add JAXB brings over XMLBeans. Am I missing
> > something?
> >
> >
> > My $0.02:
> >
> > xmlbeans is a complete and accurate representation of the xml infoset.
> >  As a result, you can easily manipulate the xml, but you get a slightly
> > peculiar java object model that exactly represents the schema and cannot be
> > modified.
> >
> > jaxb is focussed on the java pojos and lets you modify the pojos
> > considerably from the xml while still providing accurate mapping.  This can
> > be much more convenient for directly constructing a pojo tree from xml
> > suitable for configuring server components.  It provides fewer validity
> > checks than xmlbeans.
> >
> > Openejb is using jaxb and I think their deployment code is pretty simple
> > for the complexity they have to deal with.
> >
> > thanks
> > david jencks
> >
> >
> >
> >
> > On Feb 11, 2008 4:44 PM, Shiva Kumar H R <shivahr@gmail.com> wrote:
> >
> > >
> > >
> > > > Despite my liking for xmlbeans and its unique strengths I think a
> > > > very strong argument can be made for moving the deployer code to jaxb.
> > > >
> > > Interesting!! Let me do some quick learning of jaxb and start a
> > > separate thread on this.
> > >
> > >
> > > >
> > > > thanks
> > > > david jencks
> > > >
> > > > On Feb 8, 2008, at 12:30 AM, Shiva Kumar H R wrote:
> > > >
> > > > 2) Geronimo Eclipse Plug-in (GEP):
> > > >     a) Model framework for Geronimo deployment plans:
> > > > Currently it is EMF (Eclipse Modeling Framework). With every update
> > > > to Geronimo deployment schema, it's a major pain to generate new EMF
> > > > classes. If however, GEP uses the same model framework as that of Geronimo
> > > > server (XMLBeans), then at least this problem would be solved. IIUC JSR-88
> > > > DConfigBeans would be the ideal model framework for GEP - in that case
even
> > > > if the model framework of server changes in future, GEP would be unaffected.
> > > >
> > > > --
> > > > Thanks,
> > > > Shiva
> > > >
> > > >
> > > >
> > >
> > >
> > > --
> > > Thanks,
> > > Shiva
> >
> >
> >
> >
> > --
> > Thanks,
> > Shiva
> >
> >
> >
>

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