JBoss transaction interceptor, how?

the following solution was suggested by Yinon Simha (ysimha@gmail.com):

1) declare the following method inside your class:
private void interceptTransaction(Runnable beforeTxEnd, Runnable afterTxEnd)

where the 1st Runnable instance performs the logic to be performed before the TX ends, and the 2nd performs the logic after the TX ends.

2) inside this method, perform the following:

2.1) take the TransactionManager from the context like this:
Transaction tx =(Transaction) (new InitialContext()).lookup("java:/TransactionManager").getTransaction();

implement the following:
2.2) tx.registerSynchronization(new Synchronization()
{
public void beforeCompletion()
{
beforeTxEnd.run();
}

public void afterCompletion(int status)
{
if (status == Status.STATUS_COMMITTED)
{
runnable.run();
}
}
}

2.3 close the method

3) activate this method wherever you want to perform actions before and after the TX.