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[jpa-spec users] Re: Is it allowed for SFSB to return extended EntityManager to clients?

  • From: Christian von Kutzleben <cvkutzleben@...>
  • To: users@...
  • Subject: [jpa-spec users] Re: Is it allowed for SFSB to return extended EntityManager to clients?
  • Date: Tue, 29 Jan 2013 12:49:58 +0100

Hi Arne and Donatas,

Just my 2 cents regardings this:

The general case is, that the client is in another VM.

This in turn would required remoting concepts wrt. to the EntityManager, as e.g. an RMI proxy instance would be needed,
so that the actual requests really happen in the same context.

It seems not to be viable, to actually serialize the whole context to any client,
because the context would exist twice then, and some resources hold by the context might not be transferable at all.
(e.g. a JDBC connection). This leaves a remote proxy as only workable approach, and giving the lack of
any discussion of this aspect in the spec, I doubt whether this scenario was ever intended.

Personally I do also dislike this approach because it tends to break the layering of an application.

Christian

P.S. in our JDO product we had a feature once - which was dropped later - to have remote PersistenceManagers

On Tue, Jan 29, 2013 at 11:02 AM, Arne Limburg <arne.limburg@...> wrote:
Hi all,


Good issue from Donatas. I stumbled over this, too, some time ago and I
would like to extend the question:
When an entity was loaded from an extended persistence context that is
bound to a stateful session bean. Is lazy loading supposed to work outside
of the call stack of that stateful session bean, i.e. in a JSF managed
bean or a cdi bean that is directly accessed via EL?
I think it was Jboss AS 7 with Hibernate where this did not work.

Regards,
Arne

Am 29.01.13 10:56 schrieb "donatas.ciuksys@..." unter
<donatas.ciuksys@...>:

>Dear JPA experts,
>
>Could you please clarify, whether it is allowed for stateful session
>bean having container-managed extended persistence context to return
>
>its EntityManager to clients (and for clients to perform operations on
>this EntityManager), or is it forbidden?
>
>Currently, GlassFish allows returning the extended EntityManager to
>outside (e.g. http://java.net/jira/browse/GLASSFISH-11805), Apache
>OpenEJB does not, and there is currently ongoing discussion about issue
>https://issues.apache.org/jira/browse/TOMEE-509 .
>
>JPA 2.0 specification had following text (stars added by me):
>
>-----------------------------------------------
>3.3 Persistence Context Lifetime
>...
>When an extended persistence context is used, the extended persistence
>context exists from the time the
>EntityManager instance is created until it is closed. This persistence
>context might span multiple transactions
>and non-transactional invocations of the EntityManager. A
>container-managed extended persistence
>context is enlisted in the current transaction when *the EntityManager
>is invoked in the scope of
>that transaction* or when the stateful session bean to which the
>extended persistence context is bound is
>invoked in the scope of that transaction.
>-----------------------------------------------
>
>The part between ³*² seems to suggest, that EntityManager could be
>accessed by some external entity directly, not necessarily through
>
>stateful session bean method.
>I cannot find this text in JPA 2.1 public draft though.
>
>Question: can reference to extended EntityManager be provided to
>outside, and methods called on this reference?
>
>Regards,
>Donatas




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[jpa-spec users] Is it allowed for SFSB to return extended EntityManager to clients?

donatas.ciuksys 01/29/2013

[jpa-spec users] Re: Is it allowed for SFSB to return extended EntityManager to clients?

Arne Limburg 01/29/2013

[jpa-spec users] Re: Is it allowed for SFSB to return extended EntityManager to clients?

Christian von Kutzleben 01/29/2013

[jpa-spec users] Re: Is it allowed for SFSB to return extended EntityManager to clients?

Arne Limburg 01/29/2013

[jpa-spec users] Re: Is it allowed for SFSB to return extended EntityManager to clients?

Christian von Kutzleben 01/29/2013

[jpa-spec users] Re: Is it allowed for SFSB to return extended EntityManager to clients?

Donatas Čiukšys 01/29/2013

[jpa-spec users] Re: Is it allowed for SFSB to return extended EntityManager to clients?

Christian von Kutzleben 01/29/2013

[jpa-spec users] Re: Is it allowed for SFSB to return extended EntityManager to clients?

Arne Limburg 01/29/2013

[jpa-spec users] Re: Is it allowed for SFSB to return extended EntityManager to clients?

Christian von Kutzleben 01/29/2013

[jpa-spec users] Re: Is it allowed for SFSB to return extended EntityManager to clients?

Arne Limburg 01/29/2013

[jpa-spec users] Re: Is it allowed for SFSB to return extended EntityManager to clients?

Christian von Kutzleben 01/29/2013

[jpa-spec users] Re: Is it allowed for SFSB to return extended EntityManager to clients?

Donatas Čiukšys 01/29/2013

[jpa-spec users] Re: Is it allowed for SFSB to return extended EntityManager to clients?

Christian von Kutzleben 01/29/2013
 
 
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