Configuring retry behaviour for an MDB

[ojacobson]

Good afternoon.

I'm working my way towards understanding JMS and MDBs and I've encountered a roadblock.

I have a very simple MDB which accepts one message out of X (it cheats on the EJB spect and keeps a per-instance "how many messages have I recieved" count) and "rejects" the rest with context.setRollbackOnly(). When X is large enough, JBoss gives up on re-sending the message before the next "accept message" state comes up and drops the message in the DLQ.

What I want to do is instruct JBoss to retry the message indefinitely, accepting the risk of a poison message blocking any further messages from being processed. If possible I'd also like the retries to be delayed a few seconds, rather than being re-delivered immediately after transaction rollback.

What configuration changes do I need to make to have at least one of those effects?

I have the following dead-simple MDB implementation:

package xxx;

import javax.annotation.Resource;
import javax.ejb.ActivationConfigProperty;
import javax.ejb.MessageDriven;
import javax.ejb.MessageDrivenContext;
import javax.ejb.TransactionAttribute;
import javax.ejb.TransactionAttributeType;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageListener;
import javax.jms.TextMessage;

import org.apache.log4j.Logger;

@MessageDriven(activationConfig = {
 @ActivationConfigProperty(propertyName = "destinationType", propertyValue = "javax.jms.Queue"),
 @ActivationConfigProperty(propertyName = "destination", propertyValue = "queue/MDBDemo") })
public class Receiver implements MessageListener {
 private int count = 0;
 private static final int MODULUS = 100;

 private static final Logger log = Logger.getLogger(Receiver.class);

 @Resource
 private MessageDrivenContext context;

 @TransactionAttribute(TransactionAttributeType.REQUIRED)
 public void onMessage(Message message) {
 log.info("Recieve " + count + " of " + MODULUS);
 boolean accept = count == 0;

 count = (count + 1) % MODULUS;

 if (accept)
 try {
 log.info("Accepted message: "
 + ((TextMessage) message).getText());
 } catch (JMSException e) {
 log.error("JMX Exception", e);
 context.setRollbackOnly();
 }
 else {
 log.info("Rejecting message.");
 context.setRollbackOnly();
 }
 }
}

There are no deployment descriptors in the ejb-jar file (neither ejb-jar.xml nor jboss.xml).

There is no MBean descriptor for the queue/MDBDemo Queue.

The message-driven-bean invoker proxy binding in standardjboss.xml has been edited to have MaxTimesRedelivered = 3 instead of the default of 10; this does not appear to have any effect on how many times MDB delivery is attempted before JBoss gives up and sends the message to the DLQ. (Related question: will removing the DLQConfig element entirely accomplish what I want?)

All of this is running under JBoss 4.0.4.GA.

[ojacobson]

I've solved this myself; my solution is documented below.

1. For unlimited re-attempts at delivering the message, I used the ActivationConfigProperty annotations to set the "useDLQ" property of the MDB activation to "false".

2. For delayed re-attempts, configure the queue as an MBean explicity with RedeliveryDelay set to the number of milliseconds (minimum) between successive delivery attempts at the same message. This is a PER-MESSAGE delay; four messages being redelivered will cause delivery attempts to arrive 4x as fast. This was acceptable for my use case.