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entity.getAlist() reopen de emFactory and entityManager that was previously closed!! [message #527533]

Thu, 15 April 2010 10:26

No real name
Messages: 7
Registered: April 2010

Junior Member

Hello guys!
Please could anyone give me some explanation about this?

I have a entity that have a collection of other entity. This relationship is marked as :
@OneToMany(mappedBy="xxx",fetch=FetchType.LAZY,cascade={CascadeType.DETACH})

then I create a factory and an entitymanager:

emf = Persistence.createEntityManagerFactory(PERSISTENCE_UNIT_NAME );
em = emf.createEntityManager();

after I load an instance of this entity:

entity= em.find(MyEntity.class, 123L);

after that I detach this entity and close the em and emf. I test all of this using:
em.contains(entity)
em.isOpen()
emf.isOpen()

After all of this I try to itirate over the association list of my entity, like this:
for(MyEntity2 e:entity.getMyEntities2()){
print...
}

At this moment the prompt console show that the eclipselink create a new connection, and do a query to load these objects!!!
Is this a good idea? I will always get an association list even in a detached and closed instance?

I believe this feature isn't part of specification and can work differently in others implementations...

What do you think about this?
Thanks!!!

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Re: entity.getAlist() reopen de emFactory and entityManager that was previously closed!! [message #528141 is a reply to message #527533]

Mon, 19 April 2010 10:03

James Sutherland
Messages: 1834
Registered: July 2009

Senior Member

EclipseLink does support access to LAZY relationships after the EntityManager has been closed. This is undefined in the JPA spec, but it a very desirable feature.

I'm not sure what you mean by detach, if you serialize the object, it will not be able to access LAZY relationships.

If you close the EntityManagerFactory, I would expect an error, this is odd. Is there something else holding onto the same EntityManagerFactory? If there is, then close will not actually close it.

James : Wiki : Book : Blog

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Re: entity.getAlist() reopen de emFactory and entityManager that was previously closed!! [message #528249 is a reply to message #528141]

Mon, 19 April 2010 15:41

No real name
Messages: 7
Registered: April 2010

Junior Member

Thanks for the answer James!

For detach I mean call the detach() method from entityManager.

I don't know if there are something holding the EntityManagerFactory but before close I call entityManager.clear() to detach all entities and after I test if the EntityManagerFactory is open:

emf.isOpen();

and the return is false.

But even now my entity can load the lazy associations creating a new connection and doing the queries. This isn't a problem for me, but open a opportunity to the programmer work in an inappropriate way.

[Updated on: Mon, 19 April 2010 16:07]

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Re: entity.getAlist() reopen de emFactory and entityManager that was previously closed!! [message #533567 is a reply to message #527533]

Fri, 14 May 2010 11:03

No real name
Messages: 7
Registered: April 2010

Junior Member

I'm working with with app managed jpa 2.0. That is the case:

There are two entities A and B. A has a list of B.
I load an A, detach and close entityManager.

Then I iterate over A.Bs.

Now I change some value in B and commit.

I reload A and list Bs. The new value don't come back!

If I restart the program or do a listAll directly over B then I get the correct A.Bs list.

How Is the best way to work on this?

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