[jboss-user] [EJB 3.0] - JPQL polymorphic query

[juanm_med]

I have a class hierarchy of 3 Entities, one of which is the superclass for the others:

@Entity
@Table(name="PER")
@Inheritance(strategy=InheritanceType.JOINED)
@SequenceGenerator(name="SeqIdPer", sequenceName="SEQIDPER")
public abstract class Person implements Serializable {
...
}

@Entity
@Table(name="PHYPER")
@PrimaryKeyJoinColumn(name="IDPHYPER")
public class PhysicalPerson extends Person {
..
}

@Entity
@Table(name="MORALPER")
@PrimaryKeyJoinColumn(name="IDMORALPER")
public class MoralPerson extends Person {
...
}

When I execute the following JPQL:

       String strPerQuery = "SELECT OBJECT(per) FROM Person per where per.idPer = ?";                
                query=em.createQuery(strPerQuery);
                query.setParameter(1, idPerson);
                Person resPer = (Person)query.getSingleResult();

I get an object of the class Person, but I cannot downcast it to any of the subclasses. For example, even when I know that the person I sought is an instance of PhysicalPerson, the following cast throws a ClassCastException:

          PhysicalPerson phyPer = (PhysicalPerson )resPer;

Even more, when I print the runtime class of the object using resPer.getClass(), I get the following class:

mypackage.Person_$$_javassist_16 

Shouldn't the query be polymorphic, and return an object of the subclass?

I'm using JBoss 5 beta 4.

Thanks in advance.
         

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