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Combining Persistence Bundles [message #1059558]

Mon, 20 May 2013 09:00

Eclipse User

Hi,

right now i was reading Compendium Spec 5.0 and hoped to find a solution about combining persistence bundles.

I would like to provided entities contained in different bundles by one EMF. For now it is not possible. All the entities have to be contained in the same bundle.

I am looking forward to install new bundles providing entities in runtime mode. They should join the "referenced" persistence context. I now that this would require a "pre bytecode weaving" so that all the entities are "ready" for its use in the persistence context and no restart of persistence bundle has to be performed.

A solution might be using fragments. But they do not provide its own lifecycle.

1) Is there a way using gemini propietary API to do this?
2) Are there any intentions by OSGi to provide a way? Maybe with the new subsystem specification?

Thanks Florian

Re: Combining Persistence Bundles [message #1059854 is a reply to message #1059558]

Tue, 21 May 2013 19:30

Eclipse User

Hi Florian,

We have plans in Gemini JPA to provide support for multiple bundles but it will not be as dynamic as you described. All of the bundles required for a given persistence unit will need to be available in order to start using the persistence unit.

If you want entities to be added dynamically then you might want to take a closer look at the EclipseLink dynamic entities feature:

http://wiki.eclipse.org/EclipseLink/Examples/JPA/Dynamic

I haven't tried using this with Gemini JPA, but I don't think there should be any problems since it is not a matter of classloading but is all runtime jiggery-pokery. Take a look and post whether it meets your need or not.

There are no plans for OSGi to extend the JPA spec to provide any such extended functionality.

-Mike

Re: Combining Persistence Bundles [message #1059855 is a reply to message #1059854]

Tue, 21 May 2013 19:34

Eclipse User

I just remembered, you will want to use the dynamic entity API rather than the declarative virtual entities, so there is some classloading going on with the class generation, but at least you can pass in the "right" classloader.

-Mike

Re: Combining Persistence Bundles [message #1059905 is a reply to message #1059855]

Wed, 22 May 2013 03:10

Eclipse User

Hi Mike,

thanks. I took a deep look into the dynamic entity API last days. Seems to be an interesting approach.
So it should be possible to extend a PersistenceUnit with new entities at runtime.

I will follow your idea and do some more tests...

Best and thanks
Florian

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