org.hibernate.exception.GenericJDBCException: Cannot open co

[robin.hultman]

I have a SFSB with this factory:

@Factory("userSubscriptions")
 public void getUserSubscriptions() {
 userSubscriptions = em.createQuery("FROM Subscription s WHERE s.user.sign=:sign ORDER BY s.prio")
 .setParameter("sign", getCurrentUser().getSign())
 .getResultList();
 }

This collection is used as value for a datatable and works fine. When I click a button in which triggers an action in which userSubscriptions is accessed again I get:

2007-08-30 09:22:49,843 INFO [org.hibernate.event.def.DefaultLoadEventListener] Error performing load command
org.hibernate.exception.GenericJDBCException: Cannot open connection
Caused by: org.jboss.util.NestedSQLException: Transaction is not active:

To me "Cannot open connection" indicates some problem with the database but thats not possible since I do a lot of other db operations.

I think I can get around this problem by doing the transactions manually but do I really want to do that? I've had a lot of problems with this in my application so any tips would be most appreciated =).

[mvlach]

Hi, I have the same problem you are wrote. Some of DB operations succesed but some throws this exception.

[stephen.friedrich]

Typically this means there was a previous error that corrupted the transaction.

Specifically I have been getting this when trying to use MyFaces Trinidad with Sun's JSF RI. For some strange reason whenever a validation fails from that point on you'll get this error.

[wise_guybg]

I'm facing the same problem but with another idea in my mind:
http://www.jboss.com/index.html?module=bb&op=viewtopic&t=118991

I have been dealing with a similar problem in a previous project at work where we used Hibernate. The solution was to create a backing session that will help you recover gracefully in case of DBException/ContraintViolation.

I was wondering if something similar can/should be done in Seam/EJB3.

[fernando_jmt]

"wise_guybg" wrote:

I have been dealing with a similar problem in a previous project at work where we used Hibernate. The solution was to create a backing session that will help you recover gracefully in case of DBException/ContraintViolation.

I was wondering if something similar can/should be done in Seam/EJB3.

Sure, you can.

My experience as code (a simple example):

ACTION:

@Name("userAction")
@Scope(ScopeType.CONVERSATION)
public class UserAction {

 @In(required = false)
 @Out(required = false)
 private User user;

 @In(create = true)
 protected UserService userService;

 @End
 public String create() {
 try {

 userService.create(user);
 addCreatedMessage();
 return Outcome.SUCCESS;
 } catch (EntryDuplicatedException e) {
 addDuplicatedMessage();
 return null;
 }
 }
}

SERVICE:

@Stateful
@Name("userService")
@Scope(CONVERSATION)
public class UserServiceBean implements UserService {


 @In(value="#{entityManager}")
 private EntityManager em;


 public void create(User entity) throws EntryDuplicatedException {
 try {
 em.persist(entity);
 em.flush();
 } catch (EntityExistsException e) {
 throw new EntryDuplicatedException();
 }
 }

}

[wise_guybg]

Is there something special about EntryDuplicatedException?

Also, what is your experience with addDuplicatedMessage()? Does this methog try to access the database in any way?

Example of a problem:

Let's say UserAction has a method

@End
public String save()

The UserService tries to merge the user entity bean but an exception occurs (i.e. UniqueConstraint on the First+Last Name). This means that the changes to the object are invalid. In my experience if you try to use the entity manager in the catch clause you will receive a "Transaction not active" error. Then how could I reload the object and return to its persisted state?

[fernando_jmt]

EntryDuplicatedException is a custome exception I have:

@ApplicationException(rollback = true)
public class EntryDuplicatedException extends Exception {

 public EntryDuplicatedException() {
 }

}

addDuplicatedMessage() is just a simple method to add the error message to the view (FacesMessages..)

Finally, you should use @TransactionAttribute(REQUIRES_NEW) for the especific method you want to recover after the transaction fails:

@TransactionAttribute(REQUIRES_NEW)
 public void update(User entity) throws ConcurrencyException, EntryDuplicatedException {
 try {
 em.merge(entity);
 em.flush();
 } catch (EntityExistsException ee) {
 throw new EntryDuplicatedException(ee);
 }
 }