MessageGroupExample.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.JMSException;
import javax.jms.Message;
import javax.jms.MessageConsumer;
import javax.jms.MessageListener;
import javax.jms.MessageProducer;
import javax.jms.Queue;
import javax.jms.Session;
import javax.jms.TextMessage;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

import org.apache.activemq.artemis.api.jms.ActiveMQJMSClient;
import org.apache.activemq.artemis.jms.client.ActiveMQConnectionFactory;

/**
 * A simple JMS Queue example that sends and receives message groups.
 */
public class MessageGroupExample {

   public static void main(final String[] args) throws Exception {
      final Map<String, String> messageReceiverMap = new ConcurrentHashMap<>();
      Connection connection = null;
      try {

         // Step 2. Perform a lookup on the queue
         Queue queue = ActiveMQJMSClient.createQueue("queue/exampleQueue");

         // Step 3. Perform a lookup on the Connection Factory
         ActiveMQConnectionFactory cf = new ActiveMQConnectionFactory();

         // Step 4. Create a JMS Connection
         connection = cf.createConnection();

         // Step 5. Create a JMS Session
         Session session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE);

         // Step 6. Create a JMS Message Producer
         MessageProducer producer = session.createProducer(queue);

         // Step 7. Create two consumers
         MessageConsumer consumer1 = session.createConsumer(queue);
         consumer1.setMessageListener(new SimpleMessageListener("consumer-1", messageReceiverMap));
         MessageConsumer consumer2 = session.createConsumer(queue);
         consumer2.setMessageListener(new SimpleMessageListener("consumer-2", messageReceiverMap));

         // Step 8. Create and send 10 text messages with group id 'Group-0'
         int msgCount = 10;
         TextMessage[] groupMessages = new TextMessage[msgCount];
         for (int i = 0; i < msgCount; i++) {
            groupMessages[i] = session.createTextMessage("Group-0 message " + i);
            groupMessages[i].setStringProperty("JMSXGroupID", "Group-0");
            producer.send(groupMessages[i]);
            System.out.println("Sent message: " + groupMessages[i].getText());
         }

         System.out.println("all messages are sent");

         // Step 9. Start the connection
         connection.start();

         Thread.sleep(2000);

         // Step 10. check the group messages are received by only one consumer
         String trueReceiver = messageReceiverMap.get(groupMessages[0].getText());
         for (TextMessage grpMsg : groupMessages) {
            String receiver = messageReceiverMap.get(grpMsg.getText());
            if (!trueReceiver.equals(receiver)) {
               throw new IllegalStateException("Group message [" + grpMsg.getText() + "[ went to wrong receiver: " + receiver);
            }
         }

         cf.close();
      } finally {
         // Step 11. Be sure to close our JMS resources!
         if (connection != null) {
            connection.close();
         }
      }
   }
}

class SimpleMessageListener implements MessageListener {

   private final String name;
   private final Map<String, String> messageReceiverMap;

   SimpleMessageListener(final String listenerName, Map<String, String> messageReceiverMap) {
      name = listenerName;
      this.messageReceiverMap = messageReceiverMap;
   }

   @Override
   public void onMessage(final Message message) {
      try {
         TextMessage msg = (TextMessage) message;
         System.out.format("Message: [%s] received by %s%n", msg.getText(), name);
         messageReceiverMap.put(msg.getText(), name);
      } catch (JMSException e) {
         e.printStackTrace();
      }
   }
}