ClientSideFailoverListerExample.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements. See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License. You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package org.apache.activemq.artemis.jms.example;

import javax.jms.Connection;
import javax.jms.ConnectionFactory;
import javax.jms.MessageConsumer;
import javax.jms.MessageProducer;
import javax.jms.Queue;
import javax.jms.Session;
import javax.jms.TextMessage;
import javax.naming.InitialContext;

import org.apache.activemq.artemis.api.core.client.FailoverEventListener;
import org.apache.activemq.artemis.api.core.client.FailoverEventType;
import org.apache.activemq.artemis.jms.client.ActiveMQConnection;
import org.apache.activemq.artemis.util.ServerUtil;

/**
 * This example demonstrates how you can listen on failover event on the client side
 * <p/>
 * In this example there are two nodes running in a cluster, both server will be running for start,
 * but after a while the first server will crash. This will trigger a fail-over event
 */
public class ClientSideFailoverListerExample {

   private static Process server0;

   private static Process server1;

   public static void main(final String[] args) throws Exception {
      InitialContext initialContext = null;

      Connection connectionA = null;

      try {
         server0 = ServerUtil.startServer(args[0], ClientSideFailoverListerExample.class.getSimpleName() + "0", 0, 5000);
         server1 = ServerUtil.startServer(args[1], ClientSideFailoverListerExample.class.getSimpleName() + "1", 1, 0);

         // Step 1. Get an initial context for looking up JNDI from server 0
         initialContext = new InitialContext();

         // Step 2. Look-up the JMS Queue object from JNDI
         Queue queue = (Queue) initialContext.lookup("queue/exampleQueue");

         // Step 3. Look-up a JMS Connection Factory object from JNDI on server 0
         ConnectionFactory connectionFactory = (ConnectionFactory) initialContext.lookup("ConnectionFactory");

         // Step 4. We create 1 JMS connections from the same connection factory.
         // Wait a little while to make sure broadcasts from all nodes have reached the client
         Thread.sleep(5000);
         connectionA = connectionFactory.createConnection();
         ((ActiveMQConnection) connectionA).setFailoverListener(new FailoverListenerImpl());

         // Step 5. We create JMS Sessions
         Session sessionA = connectionA.createSession(false, Session.AUTO_ACKNOWLEDGE);

         // Step 6. We create JMS MessageProducer objects on the sessions
         MessageProducer producerA = sessionA.createProducer(queue);

         // Step 7. We send some messages on each producer
         final int numMessages = 10;

         for (int i = 0; i < numMessages; i++) {
            TextMessage messageA = sessionA.createTextMessage("A:This is text message " + i);
            producerA.send(messageA);
            System.out.println("Sent message: " + messageA.getText());

         }

         // Step 8. We start the connection to consume messages
         connectionA.start();

         // Step 9. We consume messages from the session A, one at a time.
         // We reached message no 5 the first server will crash
         consume(sessionA, queue, numMessages, "A");
      } finally {
         // Step 10. Be sure to close our resources!

         if (connectionA != null) {
            connectionA.close();
         }

         if (initialContext != null) {
            initialContext.close();
         }

         ServerUtil.killServer(server0);
         ServerUtil.killServer(server1);
      }
   }

   private static void consume(Session session, Queue queue, int numMessages, String node) throws Exception {
      MessageConsumer consumer = session.createConsumer(queue);

      for (int i = 0; i < numMessages; i++) {
         TextMessage message = (TextMessage) consumer.receive(2000);
         System.out.println("Got message: " + message.getText() + " from node " + node);
         if (i == 5) {
            ServerUtil.killServer(server0);
         }
      }

      System.out.println("receive other message from node " + node + ": " + consumer.receive(2000));

   }

   private static class FailoverListenerImpl implements FailoverEventListener {

      @Override
      public void failoverEvent(FailoverEventType eventType) {
         System.out.println("Failover event triggered :" + eventType.toString());
      }
   }
}