consume all messages from IBM MQ

Question

I want to consume all messages from MQ.

public static void main(String[] args)
{ 
 JMSContext context = null;
 Destination destination = null;
 JMSConsumer consumer = null;

 JmsFactoryFactory FF = JmsFactoryFactory.getInstance(WMQConstants.WMQ_PROVIDER);
 JmsConnectionFactor CF = FF.createConnectionFactory();
  context = CF.createContext();
  destination = context.createQueue(QUEUE_NAME);
  consumer = context.createConsumer(destination);
  String msg = consumer.receiveBody(String.class, 15090);
  System.out.println(msg);
 }

It is able to read one message only. How can I consume all messages? Also, is there any simpler way to delete all messages in queue without even reading or consuming them?

Answer 1

The JMS API consumes a single message at a time so you'll need to put your receiveBody in a loop, e.g.:

public static void main(String[] args) { 
   JMSContext context = null;
   Destination destination = null;
   JMSConsumer consumer = null;

   JmsFactoryFactory FF = JmsFactoryFactory.getInstance(WMQConstants.WMQ_PROVIDER);
   JmsConnectionFactor CF = FF.createConnectionFactory();
   context = CF.createContext();
   destination = context.createQueue(QUEUE_NAME);
   consumer = context.createConsumer(destination);
   String msg = null;
   do {
      msg = consumer.receiveBody(String.class, 15090);
      System.out.println(msg);
   } while (msg != null);
}

When receiveBody returns null that means there's no more messages in the queue.

The JMS API doesn't define any way to delete all the messages from a queue, but most JMS servers have an implementation-specific management API through which you can perform those sorts of actions.