Silly (maybe not ;) ) question about rollback CMT

[jacekolszak]

Hi everyone... I have a silly (maybe) question about how to roolback container managed transaction ? Now I'm using flush to prevent automaticaly send data to db after commit (so I can commit transaction after mulitple request from my web application). But how can I rollback this transaction ?

Regards
Jacek

[martinganserer]

Hello,

you have to throw a new RuntimeException() to rollback a CM transaction!

[jacekolszak]

"martin ganserer" wrote:
Hello,

you have to throw a new RuntimeException() to rollback a CM transaction!

Hm... yes.. I know... But is this only one possible way ? When i throw RuntimeException my CMB will be removed from pool :(

Look at this... :

@Statefull
class Abc {
public void method1(){
// some operations on db
}
public void rollback(){
throw new RuntimeException()
}
}

I have a client which want to rollback last update for example. So it executes rollback method and then throw runtime exception. Do you know other possible ways ?

Regards
Jacek

[martinganserer]

Hi,

I am not sure if it helps but what's about UserTransactions?
By using them you don't have to throw a RuntimeException. You can or must use commit and rollback.

[jacekolszak]

"martin ganserer" wrote:
Hi,

I am not sure if it helps but what's about UserTransactions?
By using them you don't have to throw a RuntimeException. You can or must use commit and rollback.

Thanks a lot. Now it working:

@TransactionManagement(TransactionManagementType.BEAN)
@Stateful
public class TranBean implements TranLocal {

 @PersistenceContext(type = PersistenceContextType.EXTENDED)
 protected EntityManager em;

 @Resource
 protected SessionContext ctx;

 public void test() {

 em.getTransaction().begin();
 TranEntity e = new TranEntity("Jasd");

 em.persist(e);

 }

 public void test34() {
 em.getTransaction().rollback();
 }
}

[kabirkhan]

You could keep using container managed transactions, and call SessionContext.setRollbackOnly()

[jacekolszak]

You could keep using container managed transactions, and call SessionContext.setRollbackOnly()

Ok... so using this how can I rollback transaction? (only be exception ?)

One more question - is it possible to create save points in EJB 3?

Thanks for replies
Jacek

[bill.burke]

save points? Sort of. You have to use extended persistence context and flushmode.NEVER. Basically, updates/inserts/deletes are held up until you call flush() manually.

setRollbackOnly just marks the transaction to be rolled back. YOu can also throw an Runtime, Remote, or an exception marked with @ApplicationException(rollback=true) to automatically rollback the tx.

[jacekolszak]

Ok... I've created bean which can begin, commit and rollback transaction. But now I'm trying to use other CMB from it.

em.getTransaction().begin();
TypDzial typ=new TypDzial();
typ.setNazwa("zooo");
tlocal.add(typ);
em.getTransaction().commit();

p.s. TypDzial is a CMB

But this code gives me an exception:

java.sql.SQLException: You cannot commit with autocommit set!

So.. I've set up autocommit property in persistence.xml to true - but this gives me another error -

autocommit breaks ejb 3

Is there any way to use stateless CMB inside from BMP and not allow CMB to commit the transaction automatically ? Or i must use statefull CMB and FlushMode.NEVER ?