Will your DAS implementation be SDO and JPA implementation agnostic or
will it be explicitly dependent on the EclipseLink SDO and JPA
implementations?
Naturally the goal would be to make it as portable as possible but it may
not be possible without at least some dependency on implementation
specific SDO and JPA APIs. The JPA API, for example, does not provide any
mechanism for interrogating mapping metadata. And metadata may be needed
by the DAS. It's too early to tell.