/*
* 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 org.apache.activemq.artemis.api.jms.ActiveMQJMSClient;
import org.apache.activemq.artemis.jms.client.ActiveMQConnectionFactory;
import org.apache.activemq.artemis.util.ServerUtil;
/**
* A simple example that demonstrates server side load-balancing of messages between the queue instances on different
* nodes of the cluster. The cluster is created from a static list of nodes.
*/
public class StaticClusteredQueueExample {
public static void main(final String[] args) throws Exception {
Connection initialConnection = null;
Connection connection0 = null;
Connection connection1 = null;
Connection connection2 = null;
Connection connection3 = null;
try {
// Step 2. Use direct instantiation (or JNDI if you like)
Queue queue = ActiveMQJMSClient.createQueue("exampleQueue");
// Step 3. new JMS Connection Factory object from JNDI on server 3
ConnectionFactory cf0 = new ActiveMQConnectionFactory("tcp://localhost:61619");
//grab an initial connection and wait, in reality you wouldn't do it this way but since we want to ensure an
// equal load balance we do this and then create 4 connections round robined
initialConnection = cf0.createConnection();
Thread.sleep(2000);
// Step 6. We create a JMS Connection connection0 which is a connection to server 0
connection0 = cf0.createConnection();
// Step 7. We create a JMS Connection connection1 which is a connection to server 1
connection1 = cf0.createConnection();
// Step 6. We create a JMS Connection connection0 which is a connection to server 2
connection2 = cf0.createConnection();
// Step 7. We create a JMS Connection connection1 which is a connection to server 3
connection3 = cf0.createConnection();
// Step 8. We create a JMS Session on server 0
Session session0 = connection0.createSession(false, Session.AUTO_ACKNOWLEDGE);
// Step 9. We create a JMS Session on server 1
Session session1 = connection1.createSession(false, Session.AUTO_ACKNOWLEDGE);
// Step 8. We create a JMS Session on server 2
Session session2 = connection2.createSession(false, Session.AUTO_ACKNOWLEDGE);
// Step 9. We create a JMS Session on server 3
Session session3 = connection3.createSession(false, Session.AUTO_ACKNOWLEDGE);
// Step 10. We start the connections to ensure delivery occurs on them
connection0.start();
connection1.start();
connection2.start();
connection3.start();
// Step 11. We create JMS MessageConsumer objects on server 0 server 1 server 2 server 3
MessageConsumer consumer0 = session0.createConsumer(queue);
MessageConsumer consumer1 = session1.createConsumer(queue);
MessageConsumer consumer2 = session2.createConsumer(queue);
MessageConsumer consumer3 = session3.createConsumer(queue);
Thread.sleep(2000);
// Step 12. We create a JMS MessageProducer object on server 3
MessageProducer producer = session3.createProducer(queue);
// Step 13. We send some messages to server 3
final int numMessages = 20;
for (int i = 0; i < numMessages; i++) {
TextMessage message = session0.createTextMessage("This is text message " + i);
producer.send(message);
System.out.println("Sent message: " + message.getText());
}
Thread.sleep(2000);
// Step 14. We now consume those messages on server 0 server 1 server 2 server 3
// We note the messages have been distributed between servers in a round robin fashion
// JMS Queues implement point-to-point message where each message is only ever consumed by a
// maximum of one consumer
int con0Node = ServerUtil.getServer(connection0);
int con1Node = ServerUtil.getServer(connection1);
int con2Node = ServerUtil.getServer(connection2);
int con3Node = ServerUtil.getServer(connection3);
if (con0Node + con1Node + con2Node + con3Node != 6) {
throw new IllegalStateException();
}
for (int i = 0; i < numMessages; i += 4) {
TextMessage message0 = (TextMessage) consumer0.receive(5000);
System.out.println("Got message: " + message0.getText() + " from node " + con0Node);
TextMessage message1 = (TextMessage) consumer1.receive(5000);
System.out.println("Got message: " + message1.getText() + " from node " + con1Node);
TextMessage message2 = (TextMessage) consumer2.receive(5000);
System.out.println("Got message: " + message2.getText() + " from node " + con2Node);
TextMessage message3 = (TextMessage) consumer3.receive(5000);
System.out.println("Got message: " + message3.getText() + " from node " + con3Node);
}
} finally {
// Step 15. Be sure to close our resources!
if (initialConnection != null) {
initialConnection.close();
}
if (connection0 != null) {
connection0.close();
}
if (connection1 != null) {
connection1.close();
}
if (connection2 != null) {
connection2.close();
}
if (connection3 != null) {
connection3.close();
}
}
}
}