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

Wed Nov 3 12:33:54 EDT 2010

Steve, I think I know where you coming from. And my request is to do it
*only* in the context of JPA meta-model. I'm far from making any changes to
the internals of Hibernate.
My pain point is that if EntityType is not providing me with the
@Entity.name I don't have any other means of getting that piece of
information through meta-model other than getting the entity class by name
and checking @Entity in my code, which I'd consider pretty nasty hack.
What's more FQN of entity class can be obtained not only by calling
EntityType#getName, but also by calling EntityType#getJavaType (inherited
from Type) or EntityType#getBindableJavaType (inherited form Bindable).

On Wed, Nov 3, 2010 at 3:55 PM, Steve Ebersole <steve at hibernate.org> wrote:

> I completely empathize since the JPA "metamodel" defines no other means to
> get
> at this information.  I am however nervous especially nervous about
> backporting this fix as it is a change in behavior that is far from clearly
> a
> bug.  I am kind of new to annotations so it is hard for me to say how/if
> users
> use this EntityType.getName() today.  Emmanuel?  Hardy?
>
>
> On Wednesday, November 03, 2010, at 10:34 am, Tomasz Blachowicz wrote:
> > It's up to you. I put my arguments in the ticket. I agree that jsr317
> spec
> > does not specify the correlation of the @Entity.name and
> > EntityType#getName(), but I do think it if reasonable to think that
> entity
> > name returned by the meta model and the entity name specified in the
> > annotation is the same thing. Furthermore the two other implementations
> of
> > jsp317, Apache OpenJPA and EclipseLink, went this very route.
> >
> > On Wed, Nov 3, 2010 at 2:24 PM, Steve Ebersole <steve at hibernate.org>
> wrote:
> > > 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
> > > _______________________________________________
> > > 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
>