Management Example

This example shows how to manage ActiveMQ using JMS Messages to invoke management operations on the server.

To manage ActiveMQ using JMX, see the JMX example.

Example configuration

ActiveMQ can be managed by sending JMS messages with specific properties to its management queue.

By default, the management name is called activemq.management but this can be configured in activemq-configuration.xml 
         <management-address>activemq.management</management-address>

The management queue requires a "special" user permission manage to be able to receive management messages. This is also configured in activemq-configuration.xml

         <security-setting match="activemq.management">
            <permission type="manage" roles="guest" />
         </security-setting>

Example step-by-step

To run the example, simply type mvn verify from this directory

  1. First we need to get an initial context so we can look-up the JMS connection factory and destination objects from JNDI. This initial context will get its properties from client-jndi.properties
    2.             InitialContext initialContext = getContext(0);
  2. We look up the JMS queue object from JNDI
    3.             Queue queue = (Queue) initialContext.lookup("/queue/exampleQueue");
  3. We look up the JMS connection factory object from JNDI
    4.             ConnectionFactory cf = (ConnectionFactory) initialContext.lookup("/ConnectionFactory");
  4. We create a JMS connection
    5.             connection = cf.createConnection();
  5. We create a JMS session. The session is created as non transacted and will auto acknowledge messages.
    6.             Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);
  6. We create a JMS message producer on the session. This will be used to send the messages.
    7.             MessageProducer messageProducer = session.createProducer(topic);
  7. We create a JMS text message that we are going to send.
    8.             TextMessage message = session.createTextMessage("This is a text message");
  8. We send message to the queue
    9.             messageProducer.send(message);

    Now that we have a message in the queue, we will manage the queue by retrieving the number of messages in the queue (i.e. 1) and by removing the message which has been sent in step 8.

  9. We create the JMS management queue. This is a special queue which is not looked up from JNDI but instantiated directly
    10.             Queue managementQueue = new ActiveMQQueue("activemq.management", "activemq.management");
  10. We create a QueueRequestor to send messages to the management queue and receive replies (see queue-requestor example)
    11.             QueueRequestor requestor = new QueueRequestor(session, managementQueue);
  11. We start the connection to receive replies on the requestor
    12.            connection.start()
  12. We create a JMS message which will be used as a management message
    13.             Message m = session.createMessage();
  13. a management message has well-defined properties that ActiveMQ server needs to know to perform management operations.
    We use a helper class JMSManagementHelper to fill these properties: 
    14.             JMSManagementHelper.putAttribute(m, "jms.queue.exampleQueue", "MessageCount");
  14. We send the management message using the requestor and wait for a reply
    15.             Message reply = requestor.request(m);
  15. We use a helper class JMSManagementHelper to retrieve the result from the reply message: 
                int messageCount = (Integer)JMSManagementHelper.getResult(reply);
            System.out.println(queue.getQueueName() + " contains " + messageCount + " messages");
  16. We create another JMS message to use as a management message
    17.             m = session.createMessage();
  17. This time, we fill the management message with properties to invoke a management operation on the queue 
    18.             JMSManagementHelper.putOperationInvocation(m, "jms.queue.exampleQueue", "removeMessage", message.getJMSMessageID());
  18. Again, we use the requestor to send the management message and wait for a reply
    19.             reply = requestor.request(m);
  19. We use the helper class to check that the operation was successfully invoked on the server
    20.             boolean success = JMSManagementHelper.hasOperationSucceeded(reply);
            System.out.println("operation invocation has succeeded: " + success);
  20. We use a helper class JMSManagementHelper to retrieve the result from the reply message: (in our case, the removeMessage method returns a boolean)
    21.             boolean messageRemoved = (Boolean)JMSManagementHelper.getResult(reply);
            System.out.println("message has been removed: " + messageRemoved);

    We will now consume the message from the queue but there will be none: the message sent at step 8 was removed by the management operation

  21. We create a JMS message consumer on the queue
    22.             MessageConsumer messageConsumer = session.createConsumer(queue);
  22. We try to receive a message from the queue. Since there is none, the call will timeout after 5000ms and messageReceived will be null 
    23.             TextMessage messageReceived = (TextMessage) messageConsumer.receive(5000);
            System.out.println("Received message: " + messageReceived);
  23. And finally, always remember to close your JMS connections and resources after use, in a finally block. Closing a JMS connection will automatically close all of its sessions, consumers, producer and browser objects
    24.            finally
           {
              if (initialContext != null)
              {
                initialContext.close();
              }
              if (connection != null)
              {
                 connection.close();
              }
           }

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