[hibernate-dev] [hibernate-orm] HHH-7572 - Develop API for load-by-multiple-ids (#1136)

[Steve Ebersole]

Personally I think its a questions of semantics; to me a multi-id load
already implies/indicates a certain loading strategy (Loader).  You are
saying you'd like the ability to still decide a specific loading strategy
for multi-id loads.  I seriously doubt that is really what you want, but I
do understand the desire for consistency.  Maybe some others will chime in;
tbh I'm surprised Gunnar and Sanne did not bring this up as well in terms
of integrating this with Search.

Also, that was not the question I asked.  Specifically, what is it you want
to do that you cannot do given the current call chain?



On Mon, Nov 23, 2015 at 2:07 AM Konstantin Bulanov <bulanovk at gmail.com>
wrote:

> Hello Steve, as you asked moving our discussion about HHH-7572 in dev mail
> list.
>
>
>
> Regarding you question, in current architecture and implementation we have
> the following point to perform entity persistence customization.
>
> Annotation:
>
> https://docs.jboss.org/hibernate/orm/5.0/javadocs/org/hibernate/annotations/Persister.html
> which allows us to specify our own implementation of
>
> https://docs.jboss.org/hibernate/orm/5.0/javadocs/org/hibernate/persister/entity/EntityPersister.html
> .
>
>
> One of its methods is:
>
>
>
> Object load(Serializable id,
>
>             Object optionalObject,
>
>             LockMode lockMode,
>
>             SessionImplementor session)
>
>      throws HibernateException
>
>
>
> Load an instance of the persistent class.
>
>
>
> and
>
>
>
> Object load(Serializable id,
>
>             Object optionalObject,
>
>             LockOptions lockOptions,
>
>             SessionImplementor session)
>
>      throws HibernateException
>
>
>
> Load an instance of the persistent class.
>
>
>
> These two methods allows to specify you own Loader implementation to load
> Entity by IDS,
>
> in mentioned issue this part of contract was ignored by changing call
> sequence on loading by multiple ids.
>
>
>
> By Single id;
>
>
> org.hibernate.internal.SessionImpl#get->IdentifierLoadAccessImpl->org.hibernate.internal.SessionImpl.IdentifierLoadAccessImpl#load->org.hibernate.event.spi.LoadEventListener#onLoad->org.hibernate.event.internal.DefaultLoadEventListener#loadFromDatasource->org.hibernate.persister.entity.EntityPersister#load
>
>
>
> By Multiple id:
>
>
> org.hibernate.internal.SessionImpl#byMultipleIds->org.hibernate.internal.SessionImpl.MultiIdentifierLoadAccessImpl#multiLoad->org.hibernate.loader.entity.DynamicBatchingEntityLoaderBuilder#multiLoad
>
>
>
> So in new API for multiple load we lose at least 2 possible extension
> points: onLoadEvent, Persister.load (here we could customize loader -
> specify our own instead hardcoded one)
>
>
>
> From my point of view there should be the same approach to get entities by
> ID(independent multiple or single).
>
>
> So which one approach is correct and future-proof for Single id or Multiple
> Ids?
>
>
> 20 нояб. 2015 г. 18:19 пользователь "Steve Ebersole" <
> notifications at github.com> написал:
>
> > Customize how? Loader still calls into the persister. Persisters and
> > Loaders have a back-and-forth synergy.
> >
> > Also please discuss this on the hibernate-dev mailing list so others can
> be
> > involved.
> >
> > On Fri, Nov 20, 2015 at 7:15 AM Konstantin Bulanov <
> > notifications at github.com>
> > wrote:
> >
> > > Hello Steve, could you be so kind to advice why we have different
> > behavior
> > > for loading by single id and multiple ids?
> > >
> > > In Case of single id, loading is going through
> > > session->IdentifierLoadAccess->event->persister->Loader
> > > In Case of multiple ids, loading is going through
> > > session->MultiIdentifierLoadAccess->Loader
> > >
> > > So in case of load by single id it is possible to cutomize loading of
> > > Entify using persister, but in new introduced API we lost this
> > posibility.
> > >
> > > —
> > > Reply to this email directly or view it on GitHub
> > > <
> >
> https://github.com/hibernate/hibernate-orm/pull/1136#issuecomment-158400273
> > >
> > > .
> > >
> >
> > —
> > Reply to this email directly or view it on GitHub
> > <
> https://github.com/hibernate/hibernate-orm/pull/1136#issuecomment-158413356
> >
> > .
> >
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