How do I setRollBackOnly on a sessionBean using CMT and JTA

[Jag Bains]

Hi,

I am new to J2EE v5 and I am trying to understand how CMT and JTA work

I want to rollback a transaction in Stateless SessionBean and all the documentation I have read is that I should use setRollBack on the EJBContext.

I have created a testcase where I increment a number in the DB, call the persist on the EntityManager and then try to roll it back using em.getTransaction().setRollbackOnly(); . When I do this I get returned an error

'java.lang.IllegalStateException: Exception Description: Cannot use an EntityTransaction while using JTA. ' 

I used netbeans 6.5 to create the sessionbean and the corresponding enity

Below is my session bean

    
package com.jag.sessionBeans;

import com.jag.entities.Test;
import javax.ejb.Stateless;
import javax.persistence.Query;
import javax.persistence.EntityManager;
import javax.persistence.NonUniqueResultException;
import javax.persistence.PersistenceContext;
import javax.persistence.Transient;
import org.apache.log4j.Logger;
import com.jag.entities.User;
import javax.ejb.TransactionAttribute;
import javax.ejb.TransactionAttributeType;

/**
 *  Login stateless Session bean
 * @author 
 */

@TransactionAttribute(TransactionAttributeType.REQUIRED)
@Stateless
public class LoginBean implements LoginRemote, LoginLocal {
    @PersistenceContext
    private EntityManager em;

    @Transient
    private static transient Logger log = Logger.getLogger(LoginBean.class);

    public void persist(Object object){
        em.persist(object);
    }

    public int incrementCounter(){
        log.debug("in incrementCounter");

        Query q = em.createNamedQuery("Test.findByIdtable1")
                    .setParameter("idtable1", 1);
        Test t = (Test)q.getSingleResult();
        log.debug("got back "+t);
        t.setCounter(t.getCounter()+1);
        
        persist(t);

        em.getTransaction().setRollbackOnly();

        log.debug("should have saved "+t);
        return t.getCounter();
    }
    
}

I would appreciate if someone could put me on the right track and even post an example session bean that I could use as a template.

Thanks

[Jag Bains]

I found out how

Needed to add :

@Resource
protected SessionContext ctx;

Then to rollback

ctx.setRollBackOnly();

Works a treat.