[hibernate-dev] 5.0 metamodel binding

[Steve Ebersole]

Gail,

I am working on some changes to metamodel and have come across some things
that I need your help deciphering in terms of things you do Binder.  The
background is this...

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.

Which leads to my confusion.  I have no idea how to account for such
changes in the Binder code and its calls through various executors and
contexts.  I really need some pointers here.