Question

I am receiving messages from aActive MQ queue.

Is there a way to receive a number of messages in one time? or is that have to be done with a loop?

Further more, if i want to take say 30 messages run a procedure, and only if that procedure works return a message.acknowledge(); for all of them.

I mean i dont want to erase those 30 from the queue if the procedure fails.

Thanks.

Answer 1

You’ll have to do it in a loop. Usually, it’s best to use message-driven beans for consuming messages, but it’s not suitable for this case, because they take message by message and you cannot specify the exact number. Thus, use MessageConsumer and manual transactions:

@Resource
UserTransaction utx;

@Resource(mappedName="jms/yourConnectionFactory");
ConnectionFactory cf;

@Resource(mappedName="jms/yourQueue");
Queue queue;

..    
Connection conn = null;
Session s = null;
MessageConsumer mc = null;
try {
    utx.begin();
    conn = cf.createConnection();
    s = conn.createSession(true, Session.CLIENT_ACKNOWLEDGE); //TRANSACTIONAL SESSION!
    mc = s.createConsumer(queue);
    conn.start(); // START CONNECTION'S DELIVERY OF INCOMING MESSAGES
    for(int i=0; i<30; i++)
    {
          Message msg = mc.receive();
          //BUSINESS LOGIC
    }
    utx.commit();
} catch(Exception ex) {
  ..
} finally { //CLOSE CONNECTION, SESSION AND MESSAGE CONSUMER
}