[News.eclipse.technology.eclipselink] Re: JPA: adding entities to Entity

[Rüdiger Herrmann <rherrmann@xxxxxxxxxxxxxx>]

The classes I am dealing with have JPA annotations. I wouldn't mind 
working directly with the EclipseLink implementation and already saw 
the addDescriptor() method. Only I couldn't figure out how to 
configure the ClassDescriptor.
Could you point me to the code that creates a ClassDescritor from an 
annotated class?

Thanks,
Rüdiger


James wrote:
> I think this would be a useful enhancement to EclipseLink's JPA support, 
> please log an enhancement request for it in Bugzilla.
>
> In general, EclipseLink supports adding class dynamically through its' 
> native persistence API, but not directly for the JPA API, as JPA does 
> not support this.
>
> However it should be possible to add JPA Entity classes on the fly.  You 
> can access the EclipseLink ServerSession from the 
> EntityManagerFactoryImpl (getServerSession()), and use its' 
> addDescriptor(ClassDescriptor) or addDescriptors() API to add 
> EclipseLink ClassDescriptors.  You will need to build the 
> ClassDescriptors meta-data objects directly yourself (or use the Mapping 
> Workbench to create them), as loading from JPA annotations or orm.xml 
> would be more difficult.
>
> There is also the issue of weaving the classes.  Since they may have 
> already been loaded, they will not be able to be weaved, so will not 
> support lazy ToOne's or change-tracking unless you statically weave 
> them, or use ValueHolders directly.
>
> -- James