Steve and Strong, Thanks for the clarification. This helped a lot.
I have a couple more questions inline below. ----- Original Message ----- > From: "Steve Ebersole" <steven.ebers...@gmail.com> > To: "Strong Liu" <st...@hibernate.org> > Cc: "Hibernate hibernate-dev" <hibernate-dev@lists.jboss.org>, "Gail Badner" > <gbad...@redhat.com> > Sent: Friday, January 25, 2013 9:45:26 AM > Subject: Re: [hibernate-dev] MetadataSourceProcessor and associations > > ** DISCLAIMER : Its been a long time since I have been on the > metamodel > branch, so please excuse any misuse of class/interface names... > > Comments inline... > > On Thu 24 Jan 2013 11:21:22 PM CST, Strong Liu wrote: > > > > On Jan 24, 2013, at 1:26 PM, Gail Badner <gbad...@redhat.com > > <mailto:gbad...@redhat.com>> wrote: > > > >> > >> I am trying to figure out when we have all the necessary > >> information > >> to resolve everything required for associations. > >> > >> IIUC, sources are processed in the following order by default: > >> > >> 1) HBM sources extracted from MetadataSources passed to > >> MetadataImpl > >> constructor; > >> 2) annotations sources extracted from MetadataSources passed to > >> MetadataImpl constructor; > >> 3) (annotations?) sources contributed by MetadataContributor > >> service; > >> 4) HBM sources from JaxbRoot objects produced by > >> AdditionalJaxbRootProducer service. > > > (1) and (2) are really the same thing: metadata sources explicitly > handed to MetadataSources by the app (or contributed by any defined > MetadataSourcesContributor impls). Aka, these are the known hbm.xml > and > annotation sources. Can we assume that, after 1) and 2) execute, all information (in the form of hbm/annotations source) is available to resolve all existing associations? If anything is left unresolved, should it be an exception? > > (3) the intent of MetadataContributor is for integrations to be able > to > provide additional new information to the Metadata object. Part of > that > could be contributing "mappings", however, if it were to contribute > mappings it would be in the form of the new o.h.metamodel mapping > classes already. Technically it could alter existing bindings. Can we assume that after 3) is executed that all new and pre-existing (from 1) and 2)) associations in the metadata are (still) resolved? If so, should there be a check to ensure this is true? > > (4) the intent of this, as Strong pointed out, is for Envers use > case. > Basically it lets them read the already built Metamodel (fully > resolved) > and pass us back additional JAXB mapings (hbm.xml) representing their > "version entities". To be completely honest, I always viewed this as > a > temporary hacky solution. IMO Envers should be producing full > EntityBinding graphs. But this was the path of least resistance to > get > Envers up and running on this branch as quickly as possible. > Ah, I think I get it. If Envers provided EntityBinding graphs (instead of JAXB mappings), then Envers would contribute those bindings via the MetadataContributor service. > > >> The same Binder is used create bindings from 1) and 2). A > >> different > >> Binder is used for 4). > TBH, I forget why different Binders were used. Are Envers bindings completely unrelated (in terms of subclasses/superclasses) and unassociated (in terms of one-to-one/many-to-one/one-to-many/many-to-many associations) with entity bindings produced by 1), 2), and 3)? If unrelated and unassociated with mappings provided by 1) and 2), then it makes sense that a separate Binder be used for 4). > > >> I am not familiar with how 3) and 4) are intended to be used. > Answered above > >> > >> Does 3) make "contributions" directly to the MetadataImpl? What > >> kind > >> of contributions are they? > Answered above. Could technically contribute any of the things > exposed > on the MetadataImplentor contract. > >> > >> Can 3) and 4) result in added or changed EntityBindings? > Well it would be odd for (4) to add (or change for that matter) > EntityBindings. (4) is all about creating additional "entity > bindings" > but by way of contributing back new JAXB bindings to process. (3) > Could > certainly add/change bindings. > > > > > > > IIUC, 3) is for extensions that want to create / modify metamodel ( > > binding / relational / domain ) directly > > 4) is for extensions what want to contribute hbm sources and let > > the > > Binder to do the binding stuff > > > > > > take envers as an example, for each entity with @Audit, envers > > creates > > an internal entity and associate it with the original one. > > > > the current impl ( with old metamodel ) > > > > 1. new Configuration -- mapping process > > 2. building SF > > 2.1 calling Integrator, which envers come into play, it just review > > all entities and find out the audit entities, then create hbm xml > > documents for each one, add these hbm documents into Configuration > > and > > call the buildMappings again > > 2.2 SF cons process continues, this time, the persister factory > > sees the new Configuration processed mappings ( envers created hbm > > included) > > > > so, to achieve this in the new metamodel design, extensions can > > choose > > which way is easier : > > > > 1. the same way as envers currently does (creating hbm in memory > > and > > ask hibernate to do the binding stuff) -- 4) > > 2. create/change metamodel directly -- 3) > > > > > >> > >> > >> Regards, > >> Gail > >> > >> ----- Original Message ----- > >>> > >>> From: "Steve Ebersole" <steven.ebers...@gmail.com > >>> <mailto:steven.ebers...@gmail.com>> > >>> To: "Gail Badner" <gbad...@redhat.com > >>> <mailto:gbad...@redhat.com>> > >>> Cc: "Hibernate hibernate-dev" <hibernate-dev@lists.jboss.org > >>> <mailto:hibernate-dev@lists.jboss.org>> > >>> Sent: Wednesday, January 23, 2013 11:16:23 AM > >>> Subject: Re: [hibernate-dev] MetadataSourceProcessor and > >>> associations > >>> > >>> What you mention is in fact possible. > >>> > >>> And I have never been very hopeful about the "chasing" > >>> approach... > >>> > >>> > >>> On Wed 23 Jan 2013 01:13:48 PM CST, Gail Badner wrote: > >>>> > >>>> Is it possible for an entity containing one side of an > >>>> association > >>>> be mapped using annotations and the entity containing the > >>>> opposite > >>>> side of the association be mapped using an hbm mapping? > >>>> > >>>> For example, suppose Order has annotations: > >>>> > >>>> @OneToMany( mappedby="order" ) > >>>> List<OrderLine> Order.orderLines > >>>> > >>>> OrderLine is mapped using hbm.xml with: > >>>> > >>>> <many-to-one name="order"/> > >>>> > >>>> If annotations are processed first, then, IIUC, when > >>>> Order.orderLines is processed, the mapping for OrderLine won't > >>>> be > >>>> found (via chasing) because the > >>>> AnnotationMetadataSourceProcessorImpl does not have the source > >>>> for > >>>> the OrderLine mapping. As a result, the OrderLine EntityBinding > >>>> will not be able to be built until > >>>> HbmMetadataSourceProcessorImpl > >>>> is processed. > >>>> > >>>> If so, this poses a fundamental problem with entity "chasing" as > >>>> it > >>>> is implemented now, since the associated entity would not be > >>>> processed by the same MetadataSourceProcessor. > >>>> > >>>> Am I missing something here? > >>>> > >>>> Thanks, > >>>> Gail > >>>> _______________________________________________ > >>>> hibernate-dev mailing list > >>>> hibernate-dev@lists.jboss.org > >>>> <mailto:hibernate-dev@lists.jboss.org> > >>>> https://lists.jboss.org/mailman/listinfo/hibernate-dev > >>> > >>> > >> > >> _______________________________________________ > >> hibernate-dev mailing list > >> hibernate-dev@lists.jboss.org > >> <mailto:hibernate-dev@lists.jboss.org> > >> https://lists.jboss.org/mailman/listinfo/hibernate-dev > > > > > > ------------------------- > > Best Regards, > > > > Strong Liu <stliu at hibernate.org <http://hibernate.org/>> > > http://about.me/stliu/bio > _______________________________________________ hibernate-dev mailing list hibernate-dev@lists.jboss.org https://lists.jboss.org/mailman/listinfo/hibernate-dev
