Annotation: Inheritence on primary key classes

balurian · **Posted:** Wed Apr 20, 2005 6:44 am

Hi,

I would like to use primary key classes in a hierarchy:

Code:

@Embeddable (access=AccessType.PROPERTY)
public class Cls1PK implements Serializable {
    int id1;
    
    public int getID1() {
        return id1;
    }

    .... hashCode, equals ...
}

and

Code:

@Embeddable (access=AccessType.PROPERTY)
public class Cls2PK extends Cls1PK {
    int id2;

    public int getID2() {
        return id2;
    }
}

but it doesn't seem to work.

If I use Cls2PK as @Id in some class like Cls2 Hibernate uses ID2 of class Cls2PK but ignores property ID1. That leeds to too short where clauses in update statements.

Is it just not specified to work that way? Every example file in Hibernate seems to use PK base classes without any hierarchy.

If I rewrite my class as

Code:

@Embeddable (access=AccessType.PROPERTY)
public class Cls2PK extends Cls1PK {
    int id2;

    public int getID1() {
        return super.getID1();
    }

    public int getID2() {
        return id2;
    }
}

everything works fine. But that's redundant code, isn't it?

The Annotation Version is "Version: 3.0beta1 Preview" based on EJB3 EDR2.

Thank you
Carsten

emmanuel · **Posted:** Wed Apr 20, 2005 7:09 am

Component and thus composite id class inheritance is not supported by hibernate. Sorry about that.

max · **Posted:** Wed Apr 20, 2005 7:18 am

it is supported if you write usertypes for the composite pk's....its doable ;)

balurian · **Posted:** Thu Apr 21, 2005 4:15 am

usertypes seems to be possible, but they couple a lot of my classes close to hibernate

anyway a good hint, because i found them essential at another important place

thank you

max · **Posted:** Thu Apr 21, 2005 4:25 am

No usertypes does not tie your pojo's to hibernate.

Your UserType will be dependent on Hibernate, but your primarykey classes should not BE the UserType - you should have 2 different classes.