[hibernate-dev] 5.0 metamodel binding

[Hardy Ferentschik]

On 18 Jan 2014, at 04:28, Steve Ebersole <steve at hibernate.org> wrote:

> At the moment all of metamodel binding completely mis-handles
> MappedSuperclasses.  The annotation source processor handles them somewhat,
> but in a very unusable way; it basically flattens all MappedSuperclass info
> into the nearest Entity.  This is because the source package does not at
> all support the definition of MappedSuperclass.  And then of course
> bindings do nothing with it, since it is not accounted for in source.
> 
> To add this support I plan on the following changes:
> 
> 1) Move lots of the information currently defined by RootEntitySource into
> EntityHierarchy.  The identifier, version, etc is actually a function of
> the hierarchy as a whole, so conceptually it makes more sense there anyway.
> And that mirrors the way we modeled it in the binding spi.
> 2) Generalize the EntityHierarchy tree to allow mixing Entity and
> MappedSuperclass sources.  A MappedSuperclass source actually needs to be
> defined.
> 3) Model MappedSuperclass in the binding spi as well.

+1 especially for #3. The reason the annotations side did this flattening was as you say
the fact that there was no source equivalent. I think we might have discussed this briefly
once, but affair back then we decided there was no special need to reflecting mapped 
super class in the source level.

—Hardy