Can I reuse a UserTransaction instance after commit()?

Question

Is the reusage of the ut instance in the following code correct?

UserTransaction ut = (UserTransaction)ctx.lookup("java:comp/UserTransaction");  
ut.begin();  
doSomeWork();  
ut.commit();//Or rollback (I think it doesn't matter)  
ut.begin();   //Or rollback (I think it doesn't matter)  
doOtherWork();  
ut.commit();

When the JNDI resource is defined so:

Reference atomikosUserTransactionFactoryDS = new Reference("com.atomikos.icatch.jta.UserTransactionImp", 
                "com.atomikos.icatch.jta.UserTransactionFactory", null);
atomikosUserTransactionFactoryDS.add(new RefAddr("name") {  
public Object getContent() {  
        return "UserTransaction";  
}});  
atomikosUserTransactionFactoryDS.add(new RefAddr("type") {  
    public Object getContent() {  
    return "com.atomikos.icatch.jta.UserTransactionImp";  
}});  
initContext.rebind("java:comp/UserTransaction", atomikosUserTransactionFactoryDS);

What I'm not sure about is whether I need to add another lookup, and so to retrieve a new UserTransaction from the factory, before beginning a new UserTransaction?

I don't think it's relevant but as the resource definition states I'm using Atomikos as my Transaction Manager (and so it's factory as the factory).

Thanks,
Ittai

An action should do one thing and one thing only. Why are you doing multiple things such as calling multiple transactions from within one call ? — Romain Hippeau, Nov 24 '10 at 02:28
The actual scenario is a bit different: It's more of a while(true) loop where inside the thread waits for a file and when it finds one it uses ut.begin,ut.commit. At the end of each such iteration the thread sleeps and so I commit the transaction before the sleep and when it awakes if there is a file then there is a new logical transaction. Of course you could just refactor the code, once a file is found, to another method which grabs the ut and does the logic and commits but the current design is not mine and I just wanted to verify that this is not incorrect. Thanks for your comment though. — Ittai, Nov 25 '10 at 07:52

score 4 · Accepted Answer · answered Nov 23 '10 at 13:50

reuse is ok.

UserTransaction does not represent a specific transaction instance, but rather provides a way of managing the transaction context of the current Thread. Think of it as a singleton if you like. UserTransaction is typically stateless.

An individual instance of a Transaction is a distinct entity and not normally needed directly by user code. One is created for each tx and can't be reused.

If you're a hibernate person then think in terms of SessionFactory and Session.

Can I reuse a UserTransaction instance after commit()?

1 Answers1