Inverse uniqueness in EJB 3.0 many-to-many relation

Question

Hello.
I have an @Entity class, Person, with a @ManyToMany relation with itself. This relation is the friend association. The code of the class is as follows:
@Entity
@Table(name = "PERSON", uniqueConstraints={@UniqueConstraint(columnNames={"PERSON_NAME"})})
public class Person {
     @Id
     @GeneratedValue
     @Column(name = "PERSON_ID")
     private Long id;
     @Column(name = "PERSON_NAME")
     private String name;
     @ManyToMany
     @JoinTable(name = "FRIENDS",
          joinColumns = @JoinColumn(name                     = "PERSON_A"),
          inverseJoinColumns = @JoinColumn(name                     = "PERSON_B"))
     private Set<Person> friends = new HashSet<Person>();
/*contructors, getters, setters, etc*/
The way the class is defined right now allows for the simultaneous existence of <peter, john> and <john, peter> relations when there should only be one (because john and peter are friends implies peter an john are friends). Does the Java Persistence API supply a mechanism to enforce this type of behaviour?
Any help would be apreciated.
Thanks in advance,
Hugo Oliveira
[email protected]

Answer 1

I'm afarid not - a generic feature that will allow to
delete orphan children didn't make it into the final
spec.
regards,
-marinaDo you happen to have any links to public discussions about this feature with regard to the development of the spec? This is a very nice feature in Hibernate and it's absence in EJB 3.0 is rather disappointing.
Thanks.