> I implemented a Session Bean,
if the bean is stateless, it will result into frequent construction of EMF .
> Which good practise do you propose?
construction of EMF is 'heavy' operation. You should avoid it all cost.
Implement a mechanics where EMF is created only once during the lifetime of
an application.
Scherer, Annette wrote:
>
> Hello,
>
> I use OpenJPA in a distributed J2EE Environment. I implemented a Session
> Bean, which lazy creates EntityManager and EntityManager Factory:
>
> private EntityManager getEm() {
> if (this.em == null) {
> this.em = this.getEmf().createEntityManager();
> }
> return this.em;
> }
>
> private EntityManagerFactory getEmf() {
> if (this.emf == null) {
> this.emf =
> Persistence.createEntityManagerFactory("Selektionen_DB");
> }
> return this.emf;
> }
>
> I persisted simple test objects with em.persist(...). Following calls with
> em.find(....) failed in following constellation
> - persist on clone 1
> - find on clone 2
>
>
>
> When creating EntityManager on each call (see code fragment below, without
> lazy init), it works fine. But that connat be best practice, because I
> suppose, this approach ist not as performant, it needs to be.
>
> private EntityManager getEm() {
> this.em = this.getEmf().createEntityManager();
> return this.em;
> }
>
> private EntityManagerFactory getEmf() {
> if (this.emf == null) {
> this.emf =
> Persistence.createEntityManagerFactory("Selektionen_DB");
> }
> return this.emf;
> }
>
>
> Which good practise do you propose?
>
>
> Thank you for support
> Annette Scherer
> Abteilung Informatik
>
>
>
-----
Pinaki
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