I am trying to exclude a subclass from Hibernate's polymorphic queries. I have an abstract Content class mapped with
@MappedSuperclass
@Inheritance(strategy = InheritanceType.TABLE_PER_CLASS)

I have a File class which extends Content and a FileRevision class which extends File. FileRevision is a separate table that holds all revisions that have been made to a File. We also have the same setup for Text.

Content <- Text <- TextRevision

When we query against Content we would like to find all Files and Texts, but not FileRevision nor TextRevision. When I add @Entity(polymorphism=PolymorphismType.EXPLICIT) to FileRevision Hibernate continues to union queries from the file and filerevision tables. However, when I add the same annotation to File it will not query the file nor filerevision tables and does return Text.
Is there any way I can exclude FileRevision and TextRevision from Hibernate's polymorphic query?

http://opensource.atlassian.com/project ... se/ANN-314

However, I don't fully understand the response there:

"you misunderstood polymorphism.
polymorphism explicit only applies on root entities and prevent queries naming a (unmapped) superclass to return mapped sub entities

if your case if ObjectA were not mapped and ObjectB were having polymorphism explicit, then from ObjectA would not return ObjectB elements"

Why does this only apply to "root entities?" Is there a way to have both ObjectA and ObjectB mapped, but restrict Hibernate from looking for ObjectB's unless explicitly told to (in other words, not included as part of a polymorphic query)?

Thanks.