[hibernate-dev] Entity name in the context of JPA2 meta model (HHH-5709).

Steve Ebersole steve at hibernate.org
Wed Nov 3 10:24:53 EDT 2010 

We were just discussing this on IRC.  Yes I think adding a new attribute to 
PersistentClass to capture the value of @Entity.name specifically (really we'd 
just populate it with EntityBinder.name) is best.

So we know *how* to do it.  But to be honest, I am still uncertain whether we 
*should* do it.

HHH-2597 is completely irrelevant here.  We are not discussing the Hibernate 
Criteria API here.

HHH-4375 is a bad idea.  As stated before, @Entity.name is not really in any 
way associated with Hibernate's notion of an entity name.  @Entity.name is 
what Hibernate calls a query import name.



On Wednesday, November 03, 2010, at 08:54 am, Tomasz Blachowicz wrote:
> I think I understand what you mean. "Node name" might not be indeed the
> best way to do that.
> 
> I think implementation of the EntityBinder with regards to the handling of
> @Entity.name is correct. My understanding of the jsr-317 is that the entity
> name used in queries should be @Entity.name if specified otherwise the
> default value that is unqualified name of the entity class. This is how
> EntityBinder works now I presume
> (EntityBinder#bindEjb3Annotation(@Entity)). The think is that this value
> is set to the name field of EntityBinder and then used to set
> PresistentClass#setNodeName().
> 
> I wonder how I could implement the meta model change to make sure the
> EntityType#getName() returns @Entity.name or unqualified class name in case
> the @Entity.name has not been specified. How about adding new property to
> the PersistentClass that would hot the value as computed in EntityBinder
> and the I could use the value of this property to populate EntityTypeImpl
> from MetamodelImpl#buildEntityType? Can you comment that approach?
> 
> On Wed, Nov 3, 2010 at 1:22 PM, Steve Ebersole <steve at hibernate.org> wrote:
> > Ah, I misread.  I thought you meant the Hibernate notion of an "entity
> > name".
> > As far as I can tell now looking at it, there is no such annotation equiv
> > for
> > that.
> > 
> > @javax.persistence.Entity.name is really more akin to Hibernate's notion
> > of an
> > import name for queries.
> > 
> > I am not really understanding the benefit of returning the query import
> > name
> > for EntityType.getName().  Personally I think its just a case of badly
> > matched
> > attribute names and an inference being drawn there.
> > 
> > But we do not really use that internally, so i have no qualms with
> > changing it
> > I guess.  However, I do not want "node name" used.  That is a totally
> > different beast, and if annotations ever support alternate entity modes
> > this
> > will become a problem in this code you suggest; its currently working
> > just by
> > a quirk where the default node name just happens to be the unqualified
> > entity
> > name, and I am assuming the annotation binding code is setting it if
> > @Entity.name is specified as well.  To be honest, after looking at
> > org.hibernate.cfg.annotations.EntityBinder#bindEntity my first thought
> > was whether this code even handles @Entity.name properly in terms of
> > making it an
> > import name.  It would work as is for the default case because that is
> > Hibernate's internal default behavior (to register the unqualified entity
> > name
> > as an import name).
> > 
> > On Wednesday, November 03, 2010, at 07:58 am, Steve Ebersole wrote:
> > > If that is really the case, then that is a problem with the annotation
> > > binding code.
> > > 
> > > On Wednesday, November 03, 2010, at 06:50 am, Tomasz Blachowicz wrote:
> > > > Hi Steve,
> > > > 
> > > > PersistentClass#getEntityName is not good, because it is exactly the
> > 
> > same
> > 
> > > > value as PersistentClass#getClassName.
> > > > PersistentClass#getClassName is populated in
> > > > org.hibernate.cfg.annotations.EntityBinder#bindEntity with the value
> > 
> > from
> > 
> > > > org.hibernate.annotations.common.reflection.java.JavaXClass#getName.
> > > > JavaXClass#getName is implemented as clazz.getName(), so it is always
> > > > class name and the @Entity.name is simply ignored for the purpose of
> > 
> > the
> > 
> > > > entity name. And this is the reason I used
> > > > PersistentClass#getNodeName that returns @Entity.name or
> > > > "unqualified" class name in case @Entity.name is unspecified.
> > > > 
> > > > If I'd stick with PersistentClass#getEntityName the issues is not
> > > > resolved and EntityType.getName() returns stil FQN of the class
> > > > instead of @Entity.name or "unqualified" class name.
> > > > 
> > > > Regards,
> > > > Tom
> > > > 
> > > > On Wed, Nov 3, 2010 at 11:12 AM, Steve Ebersole <steve at hibernate.org>
> > 
> > wrote:
> > > > > Uncertain yet of how these pull request comments work on GitHub, so
> > > > > I thought
> > > > > I'll make sure and respond here.  The change should use
> > > > > org.hibernate.mapping.PersistentClass#getEntityName instead of
> > > > > org.hibernate.mapping.PersistentClass#getNodeName.
> > > > > 
> > > > > See my other email to the dev list about porting to 3.6
> > > > > 
> > > > > On Wednesday, November 03, 2010, at 05:48 am, Tomasz Blachowicz
> > 
> > wrote:
> > > > > > I've submitted the pull request (
> > > > > > https://github.com/hibernate/hibernate-core/pull/8) for master. I
> > > > > > should have it also ready for 3.6 branch as soon as I manage to
> > 
> > merge
> > 
> > > > > > the change between branches in this git thng that is pretty new
> > > > > > to
> > 
> > me
> > 
> > > > > > ;)
> > > > > > 
> > > > > > On Tue, Nov 2, 2010 at 1:18 PM, Emmanuel Bernard
> > > > > 
> > > > > <emmanuel at hibernate.org>wrote:
> > > > > > > Cool :)
> > > > > > > If you use GitHub's infrastructure and use a pull-request, we
> > > > > > > can get that integrated quite fast.
> > > > > > > 
> > > > > > > On 2 nov. 2010, at 13:50, Tomasz Blachowicz wrote:
> > > > > > > 
> > > > > > > I've already created the ticket (
> > 
> > http://opensource.atlassian.com/projects/hibernate/browse/HHH-5709)
> > 
> > > > > > > . And I should be able to create the patch sometime this
> > > > > > > evening.
> > > > > > > 
> > > > > > > Cheers,
> > > > > > > Tom
> > > > > > > 
> > > > > > > On Tue, Nov 2, 2010 at 12:24 PM, Emmanuel Bernard
> > > > > 
> > > > > <emmanuel at hibernate.org>wrote:
> > > > > > >> I'd say you're correct and the name should match in the
> > 
> > metamodel.
> > 
> > > > > > >> Can you open a JIRA issue and even better try and work out a
> > > > > > >> patch?
> > > > > > >> 
> > > > > > >> PS: I've spilled hot chocolate on my laptop in the past: not
> > 
> > good,
> > 
> > > > > > >> the machine slowly but inevitably dies as corrosion wins it
> > 
> > over.
> > 
> > > > > > >> On 2 nov. 2010, at 12:35, Tomasz Blachowicz wrote:
> > > > > > >> > Hi,
> > > > > > >> > 
> > > > > > >> > I had been working recently on some stuff that deals with
> > > > > > >> > JPA2 meta
> > > > > > >> 
> > > > > > >> model.
> > > > > > >> 
> > > > > > >> > Hibernate is my JPA2 provider/engine. Everything works fine
> > > > > > >> > except
> > > > > 
> > > > > one
> > > > > 
> > > > > > >> > little thing that is name of the Entity. I'd expect that
> > > > > > >> > value returned
> > > > > > >> 
> > > > > > >> by
> > > > > > >> 
> > > > > > >> > EntityType.getName() would be the same as @Entity.name but
> > > > > > >> > not the
> > > > > 
> > > > > FQN
> > > > > 
> > > > > > >> of
> > > > > > >> 
> > > > > > >> > the entity class. Although this is not explicitly stated in
> > 
> > the
> > 
> > > > > > >> > JPA2 specification it is reasonable to expect that
> > 
> > @Entity.name
> > 
> > > > > > >> > or the
> > > > > > >> 
> > > > > > >> default
> > > > > > >> 
> > > > > > >> > value (shortened class name) is the name of the entity used
> > > > > > >> > in
> > > > > 
> > > > > queries
> > > > > 
> > > > > > >> ans
> > > > > > >> 
> > > > > > >> > well as other places such as meta model. I know the topic of
> > > > > > >> > entity name
> > > > > > >> 
> > > > > > >> was
> > > > > > >> 
> > > > > > >> > discussed  many times in the past (HHH-2597, HHH-4375,
> > 
> > HHH-4465,
> > 
> > > > > > >> HHH-5709),
> > > > > > >> 
> > > > > > >> > and the rationale has been given for current implementation
> > > > > > >> > of
> > > > > > >> 
> > > > > > >> Hibernate,
> > > > > > >> 
> > > > > > >> > however the topic hasn't been touched in the context of meta
> > > > > > >> > model that
> > > > > > >> 
> > > > > > >> is
> > > > > > >> 
> > > > > > >> > new stuff added in JPA2.
> > > > > > >> > 
> > > > > > >> > I just wanted to know what is your thinking with regards to
> > 
> > the
> > 
> > > > > matter
> > > > > 
> > > > > > >> at
> > > > > > >> 
> > > > > > >> > this stage and how likely is implementation of Hibernate
> > > > > > >> > would
> > > > > 
> > > > > change
> > > > > 
> > > > > > >> > to match EntityType.getName with @Entity.name.
> > > > > > >> > 
> > > > > > >> > P.S.
> > > > > > >> > I just have spilled the entire cup of fresh coffee on my
> > 
> > desktop
> > 
> > > > > while
> > > > > 
> > > > > > >> > writing this message. The mouse seems to be drowned :|
> > > > > > >> > 
> > > > > > >> > Cheers,
> > > > > > >> > Tom
> > > > > > >> > _______________________________________________
> > > > > > >> > hibernate-dev mailing list
> > > > > > >> > hibernate-dev at lists.jboss.org
> > > > > > >> > https://lists.jboss.org/mailman/listinfo/hibernate-dev
> > > > > > 
> > > > > > _______________________________________________
> > > > > > hibernate-dev mailing list
> > > > > > hibernate-dev at lists.jboss.org
> > > > > > https://lists.jboss.org/mailman/listinfo/hibernate-dev
> > > > > 
> > > > > ---
> > > > > Steve Ebersole <steve at hibernate.org>
> > > > > http://hibernate.org
> > > > > _______________________________________________
> > > > > hibernate-dev mailing list
> > > > > hibernate-dev at lists.jboss.org
> > > > > https://lists.jboss.org/mailman/listinfo/hibernate-dev
> > > 
> > > ---
> > > Steve Ebersole <steve at hibernate.org>
> > > http://hibernate.org
> > 
> > ---
> > Steve Ebersole <steve at hibernate.org>
> > http://hibernate.org
> > _______________________________________________
> > hibernate-dev mailing list
> > hibernate-dev at lists.jboss.org
> > https://lists.jboss.org/mailman/listinfo/hibernate-dev

---
Steve Ebersole <steve at hibernate.org>
http://hibernate.org

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