Relying on implementation-specific behavior is not good. I actually faced
the hazard. GlassFish(Eclipselink) assigned the id before @PrePersist while
WildFly(Hibernate) seems decided to follow the specification.
On 2016년 8월 16일 (화) at 20:50 Oliver Gierke <ogierke_at_pivotal.io> wrote:
> I see, that certainly makes sense. Generally speaking I don't see anything
> in the spec that should prevent implementors from behaving just the way you
> asked. Have you checked whether any of the persistence providers currently
> already behaves that way? I assume you might have more luck getting that
> feature implemented asking there first given that there's hardly any
> movement in JPA.next currently.
>
> > Am 16.08.2016 um 13:24 schrieb Jin Kwon <jinahya_at_gmail.com>:
> >
> > @Oliver
> > When GenerationType.TABLE used,
> > AS should fetch and prepare some ID values (by
> TableGenerator#allocationSize) regardless entity lifecycle
> > and assign one of them for each entity.
> > That's the very different feature against IDENTITY/SEQUENCE which each
> has to insert first and read the engine-generated(assigned) value.
> >
> > On Tue, Aug 16, 2016 at 7:47 PM, Oliver Gierke <ogierke_at_pivotal.io>
> wrote:
> > Hi Jin,
> >
> > I might be missing something obvious here but @PrePersist effectively
> implies *before* any database interaction. So how can the database
> generated be available at this time already?
> >
> > Cheers,
> > Ollie
> >
> > > Am 09.08.2016 um 11:26 schrieb Jin Kwon <jinahya_at_gmail.com>:
> > >
> > > JSR338/3.5.3 specified that
> > >
> > > Generated primary key values are available in the PostPersist method.
> > >
> > > Is it possibly to specify TABLE-generated IDs available on PrePersist?
> > >
> > > e.g.
> > > public class MyEntity {
> > >
> > > @PrePersist
> > > private void onPrePersist() {
> > > // make derived as a unique value derived from the id
> > > derived = String.format("%016x", id);
> > > }
> > >
> > > @GeneratedValue(..., strategy = GenerationType.TABLE)
> > > @Id
> > > private Long id;
> > >
> > > @Column(..., nullable = false, updatable = false)
> > > private String derived;
> > > }
>
>