transactedexample.java

JMS的例子程序

/*
 * @(#)TransactedExample.java	1.3 00/08/18
 *
 * Copyright (c) 2000 Sun Microsystems, Inc. All Rights Reserved.
 *
 * Sun grants you ("Licensee") a non-exclusive, royalty free, license to use,
 * modify and redistribute this software in source and binary code form,
 * provided that i) this copyright notice and license appear on all copies of
 * the software; and ii) Licensee does not utilize the software in a manner
 * which is disparaging to Sun.
 *
 * This software is provided "AS IS," without a warranty of any kind. ALL
 * EXPRESS OR IMPLIED CONDITIONS, REPRESENTATIONS AND WARRANTIES, INCLUDING ANY
 * IMPLIED WARRANTY OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR
 * NON-INFRINGEMENT, ARE HEREBY EXCLUDED. SUN AND ITS LICENSORS SHALL NOT BE
 * LIABLE FOR ANY DAMAGES SUFFERED BY LICENSEE AS A RESULT OF USING, MODIFYING
 * OR DISTRIBUTING THE SOFTWARE OR ITS DERIVATIVES. IN NO EVENT WILL SUN OR ITS
 * LICENSORS BE LIABLE FOR ANY LOST REVENUE, PROFIT OR DATA, OR FOR DIRECT,
 * INDIRECT, SPECIAL, CONSEQUENTIAL, INCIDENTAL OR PUNITIVE DAMAGES, HOWEVER
 * CAUSED AND REGARDLESS OF THE THEORY OF LIABILITY, ARISING OUT OF THE USE OF
 * OR INABILITY TO USE SOFTWARE, EVEN IF SUN HAS BEEN ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGES.
 *
 * This software is not designed or intended for use in on-line control of
 * aircraft, air traffic, aircraft navigation or aircraft communications; or in
 * the design, construction, operation or maintenance of any nuclear
 * facility. Licensee represents and warrants that it will not use or
 * redistribute the Software for such purposes.
 */
import java.util.*;
import javax.jms.*;

/**
 * The TransactedExample class demonstrates the use of transactions in a JMS
 * application.  It represents a highly simplified eCommerce application, in
 * which the following things happen:
 *
 * <pre>
 * Legend
 * R - Retailer
 * V - Vendor
 * S - Supplier
 * O - Order Queue
 * C - Confirmation Queue
 * ()- Thread
 * []- Queue
 *
 *                                   2(b)             3
 *          1        2(a)        /+------->[S1 O]<-----------(S1)
 *        /+-->[V O]<----+      /                             |
 *       /                \    /                      3       |
 *      /                  \  /     5      v------------------+
 *    (R)                  ( V )-------->[V C]        4
 *     \                   /  \            ^------------------+
 *      \                 /    \                              |
 *       \   7         6 /      \                             |
 *        +---->[R C]<--+        \   2(c)             4       |
 *                                +------->[SN O]<-----------(SN)
 * </pre>
 *
 * <ol>
 * <li>A retailer sends a message to the vendor order queue ordering a quantity 
 * of computers.  It waits for the vendor's reply.
 * <li>The vendor receives the retailer's order message and places an order 
 * message into each of its suppliers' order queues, all in one transaction. 
 * This JMS transaction combines one synchronous receive with multiple sends.
 * <li>One supplier receives the order from its order queue, checks its
 * inventory, and sends the items ordered to the order message's replyTo
 * field. If it does not have enough in stock, it sends what it has. 
 * The synchronous receive and the send take place in one JMS transaction.
 * <li>The other supplier receives the order from its order queue, checks its
 * inventory, and sends the items ordered to the order message's replyTo
 * field. If it does not have enough in stock, it sends what it has. 
 * The synchronous receive and the send take place in one JMS transaction.
 * <li>The vendor receives the replies from the suppliers from its confirmation 
 * queue and updates the state of the order.  Messages are processed by an 
 * asynchronous message listener; this step illustrates using JMS transactions 
 * with a message listener.
 * <li>When all outstanding replies are processed for a given order, the vendor 
 * sends a message notifying the retailer whether or not it can fulfill the 
 * order.
 * <li>The retailer receives the message from the vendor.
 * </ol>
 * <p>
 * The program contains five classes: Retailer, Vendor, GenericSupplier, 
 * VendorMessageListener, and Order.  It also contains a main method and a 
 * method that runs the threads of the Retail, Vendor, and two supplier classes.
 * <p>
 * All the messages use the MapMessage message type.  Synchronous receives are
 * used for all message reception except for the case of the vendor processing 
 * the replies of the suppliers. These replies are processed asynchronously 
 * and demonstrate how to use transactions within a message listener.
 * <p>
 * All classes except Retailer use transacted sessions.
 * <p>
 * The program uses five queues.  Before you run the program, create the
 * queues and name them A, B, C, D and E.
 * <p>
 * When you run the program, specify on the command line the number of
 * computers to be ordered.
 *
 * @author Kim Haase
 * @author Joseph Fialli
 * @version 1.3, 08/18/00
 */
public class TransactedExample {
    public static String  vendorOrderQueueName = null;
    public static String  retailerConfirmationQueueName = null;
    public static String  monitorOrderQueueName = null;
    public static String  storageOrderQueueName = null;
    public static String  vendorConfirmationQueueName = null;
    public static int     exitResult = 0;

    /**
     * The Retailer class orders a number of computers by sending a message
     * to a vendor.  It then waits for the order to be confirmed.
     * <p>
     * In this example, the Retailer places two orders, one for the quantity
     * specified on the command line and one for twice that number.
     * <p>
     * This class does not use transactions.
     *
     * @author Kim Haase
     * @author Joseph Fialli
     * @version 1.3, 08/18/00
     */
    public static class Retailer extends Thread {
        int  quantity = 0;

        /**
         * Constructor.  Instantiates the retailer with the quantity of 
         * computers being ordered.
         *
         * @param q	the quantity specified in the program arguments
         */
        public Retailer(int q) {
            quantity = q;
        }

        /**
         * Runs the thread.
         */
        public void run() {
            QueueConnectionFactory  queueConnectionFactory = null;
            QueueConnection         queueConnection = null;
            QueueSession            queueSession = null;
            Queue                   vendorOrderQueue = null;
            Queue                   retailerConfirmationQueue = null;
            QueueSender             queueSender = null;
            MapMessage              outMessage = null;
            QueueReceiver           orderConfirmationReceiver = null;
            MapMessage              inMessage = null;

            try {
                queueConnectionFactory =
                    SampleUtilities.getQueueConnectionFactory();
                queueConnection =
                    queueConnectionFactory.createQueueConnection();
                queueSession = queueConnection.createQueueSession(false,
                                                     Session.AUTO_ACKNOWLEDGE);
                vendorOrderQueue =
                    SampleUtilities.getQueue(vendorOrderQueueName, queueSession);
                retailerConfirmationQueue =
                    SampleUtilities.getQueue(retailerConfirmationQueueName, 
                                             queueSession);
            } catch (Exception e) {
                System.out.println("Connection problem: " + e.toString());
                System.out.println("Program assumes five queues named A B C D E");
                if (queueConnection != null) {
                    try {
                        queueConnection.close();
                    } catch (JMSException ee) {}
                }
                System.exit(1);
            }

            /*
             * Create non-transacted session and sender for vendor order
             * queue.
             * Create message to vendor, setting item and quantity values.
             * Send message.
             * Create receiver for retailer confirmation queue.
             * Get message and report result.
             * Send an end-of-message-stream message so vendor will
             * stop processing orders.
             */
            try {
                queueSender = queueSession.createSender(vendorOrderQueue);
                outMessage = queueSession.createMapMessage();
                outMessage.setString("Item", "Computer(s)");
                outMessage.setInt("Quantity", quantity);
                outMessage.setJMSReplyTo(retailerConfirmationQueue);
                queueSender.send(outMessage);
                System.out.println("Retailer: ordered " + quantity
                                   + " computer(s)");

                orderConfirmationReceiver =
                    queueSession.createReceiver(retailerConfirmationQueue);
                queueConnection.start();
                inMessage = (MapMessage) orderConfirmationReceiver.receive();
                if (inMessage.getBoolean("OrderAccepted") == true) {
                    System.out.println("Retailer: Order filled");
                } else {
                    System.out.println("Retailer: Order not filled");
                }
                
                
                System.out.println("Retailer: placing another order");
                outMessage.setInt("Quantity", quantity * 2);
                queueSender.send(outMessage);
                System.out.println("Retailer: ordered " 
                                   + outMessage.getInt("Quantity")
                                   + " computer(s)");
                inMessage =
                    (MapMessage) orderConfirmationReceiver.receive();
                if (inMessage.getBoolean("OrderAccepted") == true) {
                    System.out.println("Retailer: Order filled");
                } else {
                    System.out.println("Retailer: Order not filled");
                }

                // Send a non-text control message indicating end of messages.
                queueSender.send(queueSession.createMessage());
            } catch (Exception e) {
                System.out.println("Retailer: Exception occurred: " 
                                   + e.toString());
                e.printStackTrace();
                exitResult = 1;
            } finally {
                if (queueConnection != null) {
                    try {
                        queueConnection.close();
                    } catch (JMSException e) {
                        exitResult = 1;
                    }
                }
            }
        }
    }

    /**
     * The Vendor class uses one transaction to receive the computer order from
     * the retailer and order the needed number of monitors and disk drives
     * from its suppliers.  At random intervals, it throws an exception to
     * simulate a database problem and cause a rollback.
     * <p>
     * The class uses an asynchronous message listener to process replies from
     * suppliers. When all outstanding supplier inquiries complete, it sends a 
     * message to the Retailer accepting or refusing the order.
     *
     * @author Kim Haase
     * @author Joseph Fialli
     * @version 1.3, 08/18/00
     */
    public static class Vendor extends Thread {
        Random  rgen = new Random();
        int     throwException = 1;

        /**
         * Runs the thread.
         */
        public void run() {
            QueueConnectionFactory  queueConnectionFactory = null;
            QueueConnection         queueConnection = null;
            QueueSession            queueSession = null;
            QueueSession            asyncQueueSession = null;
            Queue                   vendorOrderQueue = null;
            Queue                   monitorOrderQueue = null;
            Queue                   storageOrderQueue = null;
            Queue                   vendorConfirmationQueue = null;
            QueueReceiver           vendorOrderQueueReceiver = null;
            QueueSender             monitorOrderQueueSender = null;
            QueueSender             storageOrderQueueSender = null;
            MapMessage              orderMessage = null;
            QueueReceiver           vendorConfirmationQueueReceiver = null;
            VendorMessageListener   listener = null;
            Message                 inMessage = null;
            MapMessage              vendorOrderMessage = null;
            Message                 endOfMessageStream = null;
            Order                   order = null;
            int                     quantity = 0;

            try {
                queueConnectionFactory =
                    SampleUtilities.getQueueConnectionFactory();
                queueConnection =
                    queueConnectionFactory.createQueueConnection();
                queueSession = queueConnection.createQueueSession(true, 0);
                asyncQueueSession = queueConnection.createQueueSession(true, 0);
                vendorOrderQueue =
                    SampleUtilities.getQueue(vendorOrderQueueName, queueSession);
                monitorOrderQueue =
                    SampleUtilities.getQueue(monitorOrderQueueName, queueSession);
                storageOrderQueue =
                    SampleUtilities.getQueue(storageOrderQueueName, queueSession);
                vendorConfirmationQueue =
                    SampleUtilities.getQueue(vendorConfirmationQueueName, queueSession);
            } catch (Exception e) {
                System.out.println("Connection problem: " + e.toString());
                System.out.println("Program assumes six queues named A B C D E F");
                if (queueConnection != null) {
                    try {
                        queueConnection.close();