Session.contains doesn't work

apaku · **Joined:** Thu Aug 31, 2006 7:41 am **Posts:** 24

Hi,

I've got a problem with the contains method of the Session class. It seems it's not working at all.

Code:

org.hibernate.Session hibsession = HibernateUtil.getCurrentSession();
hibsession.beginTransaction();
Instruction in = (Instruction)session.getAttribute("instr");
if(hibsession.contains(in))
  hibsession.merge(in);
else
  hibsession.saveOrUpdate(in);

This code always throws an exception telling me the object already exists in this session. The stacktrace shows that saveOrUpdate was called and not merge.

Anybody seen this before or knows what I might do wrong?

Andreas

MikePloed · **Posted:** Thu Nov 02, 2006 10:21 am

Did you implement equals and hashCode in the class you want to check?

apaku · **Joined:** Thu Aug 31, 2006 7:41 am **Posts:** 24

MikePloed wrote:

Did you implement equals and hashCode in the class you want to check?

No, and it seems I missed that paragraph in the hibernate reference :(

But why does Session not use the same algorithm for contains as for saveOrUpdate (algorithm to check wether an object is already associated with the session)?

Andreas

MikePloed · **Posted:** Thu Nov 02, 2006 11:29 am

These are two kinds of things. saveOrUpdate checks if an entity is transient (which means has it been already saved to the database). Contains checks, if the entity is bound to the session. An entity can be persistet (= not transient) but not bound to the session.