Hi
I am trying to get two or more threads waiting to access a singleton method to either:
1. block indefinitely until forward progress can proceed.
It blocks thread 2, but when Thread 1 is done, thread 2 does not resume(i.e. step 3 below does not resume). why?
2. concurrent access is not permitted.
It throws javax.ejb.ConcurrentAccessTimeoutException but I cannot get Thread 2 to rollback(i.e. step 3 below does not rollback). why?
Here is some code to give perspective to my problem:
@Singleton
@LocalBean
@Lock(WRITE) // means only one thread can access this at a time
@AccessTimeout(-1) // block indefinitely until forward progress it can proceed.
// @AccessTimeout(value = 100000) // 420000 7 minutes
// runn
// A value of -1 indicates that the client request will block indefinitely until
// forward progress it can proceed.
// 600000 10 mins
// https://docs.oracle.com/javaee/7/api/javax/ejb/AccessTimeout.html
public class NumberComponent {
/**
* Generates a list of Numbers
*
* @throws NumberGenerationException
*/
@Lock(WRITE)
public Collection<Tca01Cards> generateNumbers(…EntityManager em) throws NumberGenerationException {
}
}
@Stateless
@LocalBean
public class Thread2Component {
@EJB
NumberComponent numberComponent;
@TransactionAttribute(TransactionAttributeType.REQUIRES_NEW)
public void processUploads() {
for (Requests request : RequestsList) {
processRequest(requests);
}
}
@Transactional(rollbackOn={NumberGenerationException.class}
private void processRequest(Requests request) {
try {
//step 1
//step 2
//step 3 - do some inserts into db
//step 4
numberComponent. generateNumbers(…);
} catch (Exception ex) {
ex.printStackTrace();
}
}
}
