EntityManager.getDelegate()

ccllss · **Joined:** Wed Jan 11, 2006 9:02 am **Posts:** 11

Hi,

I have had problems to do this code work.

Code:

public class GenericEAO implements IGenericEAO {
    @PersistenceContext(unitName="Hibernate")
    protected EntityManager em;
    ...
    ...
    ...
}

@Stateless
public class MercadoriaEAO extends GenericEAO implements IMercadoriaEAO {
    public List<Mercadoria> findByExample(Mercadoria mercadoria, String[] colecoes) {
        try {
            Session hibernateSession = (Session)em.getDelegate();
            Criteria criteria = hibernateSession.createCriteria(Mercadoria.class);
            criteria.add(Example.create(mercadoria).enableLike(MatchMode.ANYWHERE));
            if(colecoes != null) {
                for(String col: colecoes) {
                    criteria.setFetchMode(col,FetchMode.JOIN);
                }
            }
            criteria.setResultTransformer(Criteria.DISTINCT_ROOT_ENTITY);
            List<Mercadoria> mercadorias = (List<Mercadoria>) criteria.list();
            hibernateSession.close();
            return mercadorias;
        } catch(Exception ex) {
            ex.printStackTrace();
            return null;
        }
    }
    ...
    ...
    ...
}

It's returning me the following exception:

Quote:

java.lang.ClassCastException: org.hibernate.ejb.EntityManagerImpl

So, Anyone could help me?

Thanks,
Cleiton

emmanuel · **Posted:** Tue Nov 06, 2007 1:44 pm

Which app server are you running on?

ccllss · **Joined:** Wed Jan 11, 2006 9:02 am **Posts:** 11

Hi Emmanuel,

I'm using Glassfish.

Thanks

andydale · **Posted:** Tue Nov 06, 2007 2:32 pm

Hi,

I have run into this problem before when running in JBoss AS. Try getting the delegate of the EntityManager.getDelegate() method, it worked for me in JBoss.

Cheers,

Andy

ccllss · **Joined:** Wed Jan 11, 2006 9:02 am **Posts:** 11

andydale wrote:

Hi,

I have run into this problem before when running in JBoss AS. Try getting the delegate of the EntityManager.getDelegate() method, it worked for me in JBoss.

Cheers,

Andy

Andy,

So, the problem is in this line:

Code:

Session hibernateSession = (Session) em.getDelegate();

This casting error happens because Glassfish inject in EntityManager interface (em variavel) this class com.sun.enterprise.util.EntityManagerWrapper. This way when I call getDelegate() method, it returns me a org.hibernate.ejb.EntityManagerImpl class which doesn't mach with Session.

Thanks

andydale · **Posted:** Tue Nov 06, 2007 3:46 pm

Hi,

I think that line is the cause, i had the exact same exception in JBoss (4.0.4) with an injected EntityManager. In the end i had to use the following call to avoid the same class cast execption as you have/had:

Code:

(Session)((EntityManagerImpl)em.getDelegate()).getDelegate();

This might (not certain though) not be the case with an application managed entity manger (obtained from an EntityManagerFactory)

Cheers,

Andy

ccllss · **Joined:** Wed Jan 11, 2006 9:02 am **Posts:** 11

Hi Andy,

That's great! It's working now.

Thanks,

emmanuel · **Posted:** Fri Nov 09, 2007 6:44 pm

Glassfish has the same bug JBoss As had