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

Tomasz Blachowicz tblachowicz at gmail.com
Mon Nov 8 03:48:28 EST 2010 

So can you guys please review my pull request to asses whether this is the
best way to implement that change? Any comments are welcome.

On Fri, Nov 5, 2010 at 7:45 PM, Emmanuel Bernard <emmanuel at hibernate.org>wrote:

> Sorry, I had a off-line week, catching up here.
>
> I think we all agree the expected behavior (according to the spec) is that
> EntityType.getName() should return @Entity.name.
> I'd say for the future major rev, we should make the change.
> I also think that the metamodel use at this stage is small enough that such
> change would only impact a few users. And there is a clear and easy API
> change for people impacted.
>
> I personally would do the move as soon as possible but I can see / respect
> the decision if people want to wait post 3.6.x (in practice that would most
> likely be Hibernate 4).
>
> On 3 nov. 2010, at 16:55, Steve Ebersole 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
>
>
> _______________________________________________
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>

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