ActiveMQ example source code file (MessageGroupNewConsumerTest.java)

This example ActiveMQ source code file (MessageGroupNewConsumerTest.java) is included in the DevDaily.com "Java Source Code Warehouse" project. The intent of this project is to help you "Learn Java by Example" ^TM.

Java - ActiveMQ tags/keywords

countdownlatch, countdownlatch, exception, jmsexception, jmsxgroupseq, message, message, messageconsumer, queue, session, string, string, thread, thread, threading, threads

The ActiveMQ MessageGroupNewConsumerTest.java source code

/**
 * 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.usecases;

import java.util.concurrent.CountDownLatch;

import javax.jms.Connection;
import javax.jms.JMSException;
import javax.jms.Message;
import javax.jms.MessageConsumer;
import javax.jms.MessageProducer;
import javax.jms.Queue;
import javax.jms.Session;
import javax.jms.TextMessage;

import org.apache.activemq.ActiveMQConnectionFactory;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import junit.framework.TestCase;

/*
 * Test plan:
 * Producer: publish messages into a queue, with three message groups
 * Consumer1: created before any messages are created
 * Consumer2: created after consumer1 has processed one message from each message group
 * 
 * All three groups are handled by to consumer1, so consumer2 should not get any messages.
 * See bug AMQ-2016: Message grouping fails when consumers are added
 */
public class MessageGroupNewConsumerTest extends TestCase {
    private static final Logger LOG = LoggerFactory.getLogger(MessageGroupNewConsumerTest.class);
    private Connection connection;
    // Released after the messages are created
    private CountDownLatch latchMessagesCreated = new CountDownLatch(1);
    // Released after one message from each group is consumed
    private CountDownLatch latchGroupsAcquired = new CountDownLatch(1);

    private static final String[] groupNames = { "GrA", "GrB", "GrC" };
    private int messagesSent, messagesRecvd1, messagesRecvd2;
    // with the prefetch too high, this bug is not realized
    private static final String connStr = "vm://localhost?broker.persistent=false&broker.useJmx=false&jms.prefetchPolicy.all=1";

    public void testNewConsumer() throws JMSException, InterruptedException {
        ActiveMQConnectionFactory factory = new ActiveMQConnectionFactory(connStr);
        connection = factory.createConnection();
        connection.start();
        final String queueName = this.getClass().getSimpleName();
        final Thread producerThread = new Thread() {
            public void run() {
                try {
                    Session session = connection.createSession(true, Session.SESSION_TRANSACTED);
                    Queue queue = session.createQueue(queueName);
                    MessageProducer prod = session.createProducer(queue);
                    for (int i=0; i<10; i++) {
                        for(String group : groupNames) {
                            Message message = generateMessage(session, group, i+1);
                            prod.send(message);
                            session.commit();
                            messagesSent++;
                        }
                        LOG.info("Sent message seq "+ (i+1));
                        if (i==0) {
                            latchMessagesCreated.countDown();
                        }
                        if (i==2) {
                            LOG.info("Prod: Waiting for groups");
                            latchGroupsAcquired.await();
                        }
                        Thread.sleep(20);
                    }
                    LOG.info(messagesSent+" messages sent");
                    prod.close();
                    session.close();
                } catch (Exception e) {
                    LOG.error("Producer failed", e);
                }
            }
        };
        final Thread consumerThread1 = new Thread() {
            public void run() {
                try {
                    Session session = connection.createSession(true, Session.SESSION_TRANSACTED);
                    Queue queue = session.createQueue(queueName);
                    MessageConsumer con1 = session.createConsumer(queue);
                    latchMessagesCreated.await();
                    while(true) {
                        Message message = con1.receive(1000);
                        if (message == null)  break;
                        LOG.info("Con1 got message "+formatMessage(message));
                        session.commit();
                        messagesRecvd1++;
                        // since we get the messages in order, the first few messages will be one from each group
                        // after we get one from each group, start the other consumer
                        if (messagesRecvd1 == groupNames.length) {
                            LOG.info("All groups acquired");
                            latchGroupsAcquired.countDown();
                            Thread.sleep(1000);
                        }
                        Thread.sleep(50);
                    }
                    LOG.info(messagesRecvd1+" messages received by consumer1");
                    con1.close();
                    session.close();
                } catch (Exception e) {
                    LOG.error("Consumer 1 failed", e);
                }
            }
        };
        final Thread consumerThread2 = new Thread() {
            public void run() {
                try {
                    latchGroupsAcquired.await();
                    while(consumerThread1.isAlive()) {
                        LOG.info("(re)starting consumer2");
                        Session session = connection.createSession(true, Session.SESSION_TRANSACTED);
                        Queue queue = session.createQueue(queueName);
                        MessageConsumer con2 = session.createConsumer(queue);
                        while(true) {
                            Message message = con2.receive(500);
                            if (message == null) break;
                            LOG.info("Con2 got message       "+formatMessage(message));
                            session.commit();
                            messagesRecvd2++;
                            Thread.sleep(50);
                        }
                        con2.close();
                        session.close();
                    }
                    LOG.info(messagesRecvd2+" messages received by consumer2");
                } catch (Exception e) {
                    LOG.error("Consumer 2 failed", e);
                }
            }
        };
        consumerThread2.start();
        consumerThread1.start();
        producerThread.start();
        // wait for threads to finish
        producerThread.join();
        consumerThread1.join();
        consumerThread2.join();
        connection.close();
        // check results
        assertEquals("consumer 2 should not get any messages", 0, messagesRecvd2);
        assertEquals("consumer 1 should get all the messages", messagesSent, messagesRecvd1);
        assertTrue("producer failed to send any messages", messagesSent > 0);
    }

    public Message generateMessage(Session session, String groupId, int seq) throws JMSException {
        TextMessage m = session.createTextMessage();
        m.setJMSType("TEST_MESSAGE");
        m.setStringProperty("JMSXGroupID", groupId);
        m.setIntProperty("JMSXGroupSeq", seq);
        m.setText("<?xml?>");
        return m;
    }
    public String formatMessage(Message m) {
        try {
            return m.getStringProperty("JMSXGroupID")+"-"+m.getIntProperty("JMSXGroupSeq")+"-"+m.getBooleanProperty("JMSXGroupFirstForConsumer");
        } catch (Exception e) {
            return e.getClass().getSimpleName()+": "+e.getMessage();
        }
    }
}