It would be nice if Morphia supported "mixin" annotations akin to the ones found in Jackson.

ie., given a domain object:

class Obj {
  int oid;
  double[] vals;
}

That I want to persist via Morphia & Mongo, but don't want to add annotations to the class. So I want to be able to define the annotations/persistence information outside of that class in something like:

@Entity class ObjMixin {
  @Id int oid;
  double[] vals;
}

And then somewhere in the mapping code do something like:

datastore.mapWith(Obj.class, ObjMixin.class)

Mapping in JSON or XML would also work.