Java tutorial
/** * 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. */ import java.util.Arrays; 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.Session; import javax.jms.TextMessage; import javax.jms.Topic; import org.apache.activemq.ActiveMQConnectionFactory; /** * Use in conjunction with TopicPublisher to test the performance of ActiveMQ * Topics. */ public class TopicListener implements MessageListener { private Connection connection; private MessageProducer producer; private Session session; private int count; private long start; private Topic topic; private Topic control; private String url = "tcp://localhost:61616"; public static void main(String[] argv) throws Exception { TopicListener l = new TopicListener(); String[] unknown = CommandLineSupport.setOptions(l, argv); if (unknown.length > 0) { System.out.println("Unknown options: " + Arrays.toString(unknown)); System.exit(-1); } l.run(); } public void run() throws JMSException { ActiveMQConnectionFactory factory = new ActiveMQConnectionFactory(url); connection = factory.createConnection(); session = connection.createSession(false, Session.AUTO_ACKNOWLEDGE); topic = session.createTopic("topictest.messages"); control = session.createTopic("topictest.control"); MessageConsumer consumer = session.createConsumer(topic); consumer.setMessageListener(this); connection.start(); producer = session.createProducer(control); System.out.println("Waiting for messages..."); } private static boolean checkText(Message m, String s) { try { return m instanceof TextMessage && ((TextMessage) m).getText().equals(s); } catch (JMSException e) { e.printStackTrace(System.out); return false; } } public void onMessage(Message message) { if (checkText(message, "SHUTDOWN")) { try { connection.close(); } catch (Exception e) { e.printStackTrace(System.out); } } else if (checkText(message, "REPORT")) { // send a report: try { long time = System.currentTimeMillis() - start; String msg = "Received " + count + " in " + time + "ms"; producer.send(session.createTextMessage(msg)); } catch (Exception e) { e.printStackTrace(System.out); } count = 0; } else { if (count == 0) { start = System.currentTimeMillis(); } if (++count % 1000 == 0) { System.out.println("Received " + count + " messages."); } } } public void setUrl(String url) { this.url = url; } }