simpleasynchconsumer.java

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/*
 * Copyright (c) 2003 Sun Microsystems, Inc.  All rights reserved.  U.S. 
 * Government Rights - Commercial software.  Government users are subject 
 * to the Sun Microsystems, Inc. standard license agreement and 
 * applicable provisions of the FAR and its supplements.  Use is subject 
 * to license terms.  
 * 
 * This distribution may include materials developed by third parties. 
 * Sun, Sun Microsystems, the Sun logo, Java and J2EE are trademarks 
 * or registered trademarks of Sun Microsystems, Inc. in the U.S. and 
 * other countries.  
 * 
 * Copyright (c) 2003 Sun Microsystems, Inc. Tous droits reserves.
 * 
 * Droits du gouvernement americain, utilisateurs gouvernementaux - logiciel
 * commercial. Les utilisateurs gouvernementaux sont soumis au contrat de 
 * licence standard de Sun Microsystems, Inc., ainsi qu'aux dispositions 
 * en vigueur de la FAR (Federal Acquisition Regulations) et des 
 * supplements a celles-ci.  Distribue par des licences qui en 
 * restreignent l'utilisation.
 * 
 * Cette distribution peut comprendre des composants developpes par des 
 * tierces parties. Sun, Sun Microsystems, le logo Sun, Java et J2EE 
 * sont des marques de fabrique ou des marques deposees de Sun 
 * Microsystems, Inc. aux Etats-Unis et dans d'autres pays.
 */
/**
 * The SimpleAsynchConsumer class consists only of a main
 * method, which receives one or more messages from a queue or
 * topic using asynchronous message delivery.  It uses the 
 * message listener TextListener.  Run this program in 
 * conjunction with SimpleProducer.  
 *
 * Specify a queue or topic name on the command line when you run
 * the program. To end the program, type Q or q on the command 
 * line.
 */
import javax.jms.*;
import javax.naming.*;
import java.io.*;

public class SimpleAsynchConsumer {

    /**
     * Main method.
     *
     * @param args     the destination name and type used by the 
     *                 example
     */
    public static void main(String[] args) {
        String             destName = null;
        String             destType = null;
        Context            jndiContext = null;
        ConnectionFactory  connectionFactory = null;
        Connection         connection = null;
        Session            session = null;
        Destination        dest = null;
        MessageConsumer    consumer = null;
        TextListener       listener = null;
        TextMessage        message = null;
        InputStreamReader  inputStreamReader = null;
        char               answer = '\0';
                
        if (args.length != 2) {
            System.out.println("Program takes two arguments: " +
                "<dest_name> <queue|topic>");
            System.exit(1);
        }
        destName = new String(args[0]);
        destType = new String(args[1]);
        System.out.println("Destination name is " + destName +
            ", type is " + destType);

        /* 
         * Create a JNDI API InitialContext object if none exists
         * yet.
         */
        try {
            jndiContext = new InitialContext();
        } catch (NamingException e) {
            System.out.println("Could not create JNDI API " +
                "context: " + e.toString());
            System.exit(1);
        }

        /* 
         * Look up connection factory and destination.  If either
         * does not exist, exit.  If you look up a 
         * TopicConnectionFactory instead of a 
         * QueueConnectionFactory, program behavior is the same.
         */
        try {
            connectionFactory = (ConnectionFactory)
                jndiContext.lookup("jms/QueueConnectionFactory");
            if (destType.equals("queue")) {
                dest = (Queue) jndiContext.lookup(destName);
            } else if (destType.equals("topic")) {
                dest = (Topic) jndiContext.lookup(destName);
            } else {
                throw new Exception("Invalid destination type" +
                    "; must be queue or topic");
            }
        } catch (Exception e) {
            System.out.println("JNDI API lookup failed: " +
                e.toString());
            System.exit(1);
        }

        /*
         * Create connection.
         * Create session from connection; false means session is
         * not transacted.
         * Create consumer.
         * Register message listener (TextListener).
         * Receive text messages from destination.
         * When all messages have been received, type Q to quit.
         * Close connection.
         */
        try {
            connection = connectionFactory.createConnection();
            session = connection.createSession(false, 
                Session.AUTO_ACKNOWLEDGE);
            consumer = session.createConsumer(dest);
            listener = new TextListener();
            consumer.setMessageListener(listener);
            connection.start();
            System.out.println("To end program, type Q or q, " +
                "then <return>");
            inputStreamReader = new InputStreamReader(System.in);
            while (!((answer == 'q') || (answer == 'Q'))) {
                try {
                    answer = (char) inputStreamReader.read();
                } catch (IOException e) {
                    System.out.println("I/O exception: " 
                        + e.toString());
                }
            }
        } catch (JMSException e) {
            System.out.println("Exception occurred: " +
                e.toString());
        } finally {
            if (connection != null) {
                try {
                    connection.close();
                } catch (JMSException e) {}
            }
        }
    }
}