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QWBrowser.javaAPI DocExample8813Wed Dec 06 18:58:12 GMT 2000chap5.b2b

QWBrowser

public class QWBrowser extends Object implements javax.jms.MessageListener

Fields Summary
private javax.jms.TopicConnection
tConnect
private javax.jms.TopicSession
tSession
private javax.jms.TopicPublisher
tPublisher
private javax.jms.QueueConnection
qConnect
private javax.jms.QueueSession
qSession
private javax.jms.QueueReceiver
qReceiver
private javax.jms.Queue
receiveQueue
private javax.jms.Topic
hotDealsTopic
private javax.jms.TemporaryTopic
buyOrdersTopic
private String
uname
Constructors Summary
public QWBrowser(String broker, String username, String password)


          
      try{
        TopicConnectionFactory tFactory = null;
        QueueConnectionFactory qFactory = null;
        InitialContext jndi = null;
        uname = username;

        Properties env = new Properties();
        // ... specify the JNDI properties specific to JNDI SPI being used
        env.put("BROKER",broker);
        jndi = new InitialContext(env);

        tFactory =
            (TopicConnectionFactory)jndi.lookup("TopicConnectionFactory");
        qFactory =
            (QueueConnectionFactory)jndi.lookup("QueueConnectionFactory");
        tConnect = tFactory.createTopicConnection (username, password);
        qConnect = qFactory.createQueueConnection (username, password);

        tSession =
            tConnect.createTopicSession(false,Session.AUTO_ACKNOWLEDGE);
        qSession =
            qConnect.createQueueSession(false,Session.AUTO_ACKNOWLEDGE);

        hotDealsTopic = (Topic)jndi.lookup("Hot Deals");
        receiveQueue = (Queue)jndi.lookup("Reply Q");

        tPublisher = tSession.createPublisher(hotDealsTopic);

        // Now that setup is complete, start the Connection
        tConnect.start();
      }catch (javax.jms.JMSException jmse){
         jmse.printStackTrace(); System.exit(1);
      }catch(javax.naming.NamingException jne){
         jne.printStackTrace(); System.exit(1);
      }
   
Methods Summary
private intexamineQueue(int inStockQty)

        int cnt = 0;
        int bestQty = 0;
        try{
            // qConnect.start();
            System.out.println("In Stock QTY: " + inStockQty);
            System.out.print ( "Creating QueueBrowser..." );
            javax.jms.QueueBrowser browser
                = qSession.createBrowser(receiveQueue);
            System.out.println ("[done]");

            java.util.Enumeration e = browser.getEnumeration();
            while(e.hasMoreElements()){
                System.out.print(" --> getting message "
                + String.valueOf(++cnt) + "...");
                javax.jms.TextMessage message =
                    (javax.jms.TextMessage) e.nextElement();
                System.out.println("[" + message.getText() + "]");
                if (message != null){
                    int orderQty = message.getIntProperty("QTY");
                    if( orderQty > bestQty && orderQty <= inStockQty)
                        bestQty = orderQty;
                }
            }
            // Free any resources in the browser.
            browser.close();
        }catch( javax.jms.JMSException jmse ){
            jmse.printStackTrace();
        }
        System.out.println("\nBestQty: " + bestQty);
        return bestQty;
    
public voidexit()

      try{
        tConnect.close();
        qConnect.close();
      }catch (javax.jms.JMSException jmse){
        jmse.printStackTrace();
      }
      System.exit(0);
   
public static voidmain(java.lang.String[] argv)

    String broker, username, password;
    if(argv.length == 3){
        broker = argv[0];
        username = argv[1];
        password = argv[2];
    }else{
        System.out.println("Invalid arguments. Should be: ");
        System.out.println("java QWholesaler broker username password");
        return;
    }

    QWBrowser wholesaler = new QWBrowser(broker, username, password);
    wholesaler.processInput();
   
public voidonMessage(javax.jms.Message message)

      try{
         TextMessage textMessage = (TextMessage) message;
         String text = textMessage.getText();
         System.out.println("Order received - "+text+
                            " from " + message.getJMSCorrelationID());
      }catch (java.lang.Exception rte){
         rte.printStackTrace();
      }
   
public voidprocessInput()

    try{
        // Read all standard input and send it as a message.
        java.io.BufferedReader stdin = new java.io.BufferedReader
            (new java.io.InputStreamReader( System.in ) );
        while ( true ){
            System.out.println ("Enter: Item, Old Price, New Price ");
            System.out.println("\ne.g. Bowling Shoes, 100.00, 55.00");
            String dealDesc = stdin.readLine();
            if(dealDesc != null && dealDesc.length() > 0){
                // parse the deal description
                StringTokenizer tokenizer =
                new StringTokenizer(dealDesc,",") ;
                    String itemDesc = tokenizer.nextToken();
                    String temp = tokenizer.nextToken();
                    float oldPrice =
                        Float.valueOf(temp.trim()).floatValue();
                    temp = tokenizer.nextToken();
                    float newPrice =
                        Float.valueOf(temp.trim()).floatValue();

                publishPriceQuotes(dealDesc,uname,
                    itemDesc, oldPrice,newPrice);
                int inStockQty =
                    (int)(java.lang.Math.random() * (double)1000);
                int bestQty = examineQueue(inStockQty);
                qConnect.start();
                javax.jms.TextMessage textMessage = null;
                while( true )
                {
                    textMessage =
                        (javax.jms.TextMessage)qReceiver.receive(1000);
                    if ( textMessage == null ){
                        qConnect.stop();
                        break;  // no more messages to get
                    }

                    String text = textMessage.getText();
                    int qty = textMessage.getIntProperty("QTY");
                    System.out.println("\nOrder received - "+text+
                        " from " + textMessage.getJMSCorrelationID());

                    // could have missed the first one
				    if( qty > bestQty && qty <= inStockQty)
					    bestQty = qty;
                    if (qty == bestQty){
                        System.out.println("Fulfilling order");
                        // Do some processing to fulfill order
                    }else{
                        System.out.println("Placing in BACK-ORDER status");
                        // Do some processing to create BACK-ORDER status
                    }
                }
            }else{
                this.exit();
            }
        }
    }catch (javax.jms.JMSException jmse){
        jmse.printStackTrace();
    }catch( java.io.IOException ioe ){
        ioe.printStackTrace();
    //}catch( java.lang.InterruptedException ie ){
    //    ie.printStackTrace();
    }
private voidpublishPriceQuotes(java.lang.String dealDesc, java.lang.String username, java.lang.String itemDesc, float oldPrice, float newPrice)

      try{
        javax.jms.StreamMessage message = tSession.createStreamMessage();
        message.writeString(dealDesc);
        message.writeString(itemDesc);
        message.writeFloat(oldPrice);
        message.writeFloat(newPrice);

        message.setStringProperty("Username", username);
        message.setStringProperty("itemDesc", itemDesc);

        message.setJMSReplyTo(receiveQueue);

        tPublisher.publish(
            message,
            javax.jms.DeliveryMode.PERSISTENT,
            javax.jms.Message.DEFAULT_PRIORITY,
            1800000);
      }catch ( javax.jms.JMSException jmse ){
         jmse.printStackTrace();
      }