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From Kevin Sutter <kwsut...@gmail.com>
Subject Re: JPA 3.0
Date Wed, 12 May 2010 14:10:41 GMT
:-)  Thanks, Laird.  This is the type of processing that I was envisioning
with Christopher's post.  Neat, cool idea.  But, I'm still looking for the
practicality of the proposal.  From what I am reading on the EclipseLink
site, doing something similar in OpenJPA certainly looks doable.  I just
don't see it rising on my priority list...  :-)  Any other takers?

Kevin

On Wed, May 12, 2010 at 8:39 AM, ljnelson <ljnelson@gmail.com> wrote:

>
> Interestingly, this just came up over in EclipseLink land:
> http://wiki.eclipse.org/EclipseLink/Examples/JPA/Dynamic
>
> Best,
> Laird
>
> On Wed, May 12, 2010 at 9:36 AM, Kevin Sutter [via OpenJPA] <
> ml-node+5041111-372614786-210534@n2.nabble.com<ml-node%2B5041111-372614786-210534@n2.nabble.com>
> <ml-node%2B5041111-372614786-210534@n2.nabble.com<ml-node%252B5041111-372614786-210534@n2.nabble.com>
> >
> > wrote:
>
> > Hi Christopher,
> > Hmmm...  Interesting idea, but is this dynamic mapping really practical?
> >  It
> > sounds like you are looking for the means to dynamically create or change
> > the mappings defined by your Entity and your database Schema.  The
> > attribute
> > types in your Entity definitions will need to match (or at least easily
> > convert to) the types in your database Schema.  Since most customer
> > database
> > schemas are fairly static, I don't quite see the need for dynamic
> mappings.
> >
> >
> > Maybe I need another cup of coffee this morning, but I'd still be
> > interested
> > in hearing a specific, real-world use case where the mappings between
> your
> > Entity and Schema need to be dynamic.
> >
> > Thanks,
> > Kevin
> >
> > On Tue, May 11, 2010 at 11:33 AM, Christopher Gardner <
> > [hidden email] <http://user/SendEmail.jtp?type=node&node=5041111&i=0>>
> > wrote:
> >
> > > Kevin,
> > >
> > > The only use case I can think of is the obvious one: a mapping system
> > > more expressive and typesafe than xml,  while allowing for refactoring
> > and
> > > clutter-free entity code.  However--and this is just coming off the top
> > of
> > > my head as I'm writing--I wonder if there might be needs to compute
> > > mappings
> > > based on dynamic criteria rather than be bound to compiled annotations
> or
> >
> > > static xml (of course, I can't think of what those needs are at the
> > > moment).
> > >
> > > On Tue, May 11, 2010 at 12:21 PM, Kevin Sutter <[hidden email]<
> http://user/SendEmail.jtp?type=node&node=5041111&i=1>>
> > wrote:
> > >
> > > > Hi Christopher,
> > > > Now I see what you meant by a "fluent API"...  To be honest, my
> > viewpoint
> > > > of
> > > > this API was to allow for an alternate means of configuring
> Hibernate,
> > > > other
> > > > than just using XML.  Classic Hibernate only supported configuration
> > > > through
> > > > XML, so this fluentHibernate allowed for a programming-based
> mechanism
> > > for
> > > > configuration.  On the surface, it seems like this would be more
> > > difficult
> > > > to use than just using annotations.
> > > >
> > > > Can you provide any use cases in the JPA sense that would describe
> how
> > > this
> > > > type of configuration API would be helpful?
> > > >
> > > > On a similar vein, we are considering an API to help with
> configuration
> >
> > > of
> > > > the persistence unit.  Since the persistence unit is defined by the
> > > > persistence.xml only, allowing some alternate means via an API would
> be
> >
> > > > welcome.
> > > >
> > > > Kevin
> > > >
> > > > On Tue, May 11, 2010 at 10:27 AM, Christopher Gardner <
> > > > [hidden email] <http://user/SendEmail.jtp?type=node&node=5041111&i=2
> >>
> > wrote:
> > > >
> > > > > Thanks.  I'm in the former camp, i.e., a legacy database.  I'm
> aware
> > of
> > > > the
> > > > > xml alternative.  Though I'm no DotNet developer, I read about an
> > > Fluent
> > > > > NHibernate, which allows you to create a object to store mapping
in
> > > code.
> > > > >
> > > > > http://wiki.fluentnhibernate.org/Getting_started
> > > > >
> > > > > <http://wiki.fluentnhibernate.org/Getting_started>Maybe such
an
> API
> > > > isn't
> > > > > appropriate for a spec, but it would be an interesting alternative
> to
> >
> > > > both
> > > > > annotations and xml for JPA.
> > > > >
> > > > > On Tue, May 11, 2010 at 11:21 AM, Kevin Sutter <[hidden email]<
> http://user/SendEmail.jtp?type=node&node=5041111&i=3>>
> >
> > > > wrote:
> > > > >
> > > > > > Hi Christopher,
> > > > > > You're right, annotations can be verbose.  But, they don't have
> to
> > > be.
> > > > >  It
> > > > > > all depends on whether your application can live with the default
> > > > > > processing
> > > > > > defined by the spec.  We tried to pick the most common default
> > values
> > > > for
> > > > > > the various annotation elements.  If your application can live
> with
> >
> > > the
> > > > > > default processing, then all that is really necessary is the
> > @Entity
> > > > and
> > > > > > @Id
> > > > > > annotations.  But, most legacy applications and schemas can
not
> > live
> > > > with
> > > > > > the default settings, thus the annotations can become verbose.
> > > > >  Flexibility
> > > > > > can be a killer...  But, then we'd be crucified if we didn't
> allow
> > > for
> > > > > the
> > > > > > flexibility...  :-)
> > > > > >
> > > > > > The annotations can also be overridden via orm.xml declarations.
> > >  This
> > > > > > would
> > > > > > keep your base code more readable, while putting the detailed
> gorp
> > > into
> > > > > the
> > > > > > xml file(s).  Maybe this would be more suitable for your
> > environment.
> > > > > >
> > > > > > Not sure what you mean by "fluent API".  Any specific examples
to
> > > help
> > > > > with
> > > > > > this discussion?
> > > > > >
> > > > > > Thanks,
> > > > > > Kevin
> > > > > >
> > > > > > On Tue, May 11, 2010 at 10:10 AM, Christopher Gardner <
> > > > > > [hidden email]<
> http://user/SendEmail.jtp?type=node&node=5041111&i=4>>
> > wrote:
> > > > > >
> > > > > > > Vis-a-vis all JPA specs, streamlining annotations would
be
> nice.
> > >  The
> > > > > > > annotations can be verbose.  Maybe a fluent API would be
in
> > order.
> > > > > > >
> > > > > > > On Tue, May 11, 2010 at 10:46 AM, Kevin Sutter <[hidden
email]<
> http://user/SendEmail.jtp?type=node&node=5041111&i=5>
> > > >
> > > > > > wrote:
> > > > > > >
> > > > > > > > Hi Chris,
> > > > > > > > Sorry to hear that you are frustrated with JPA 2.0.
 Can you
> > > > > elaborate?
> > > > > > > >  The
> > > > > > > > JPA Expert Group is currently soliciting feedback
for the
> next
> > > > > revision
> > > > > > > of
> > > > > > > > the JPA spec (2.x or 3.0).  Here's the e-mail address
for
> this
> > > > > > > > correspondence [1].  But, if there are distinct improvements
> > that
> > > > are
> > > > > > you
> > > > > > > > looking for, maybe they could be entertained by the
OpenJPA
> > > > community
> > > > > > > > first.  Bugs and/or Features can be entered into our
JIRA
> > system
> > > > [2]
> > > > > > for
> > > > > > > > future consideration.  Of course, community involvement
can
> > help
> > > > > speed
> > > > > > up
> > > > > > > > this process.
> > > > > > > >
> > > > > > > > Thanks for the input,
> > > > > > > > Kevin
> > > > > > > >
> > > > > > > > [1]  [hidden email]<
> http://user/SendEmail.jtp?type=node&node=5041111&i=6>
> > > > > > > > [2]  https://issues.apache.org/jira/browse/OPENJPA
> > > > > > > >
> > > > > > > > On Tue, May 11, 2010 at 9:12 AM, C N Davies <[hidden
email]<
> http://user/SendEmail.jtp?type=node&node=5041111&i=7>>
> >
> > > > > wrote:
> > > > > > > >
> > > > > > > > > I'm so frustrated by JPA 2.0 but can't seem to
find an JSR
> > for
> > > > JPA
> > > > > 3
> > > > > > or
> > > > > > > > > anything. Can anyone point me it?
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > Thanks J
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > > Chris
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > > >
> > > > > > > >
> > > > > > >
> > > > > >
> > > > >
> > > >
> > >
> >
> >
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