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Wholesaler.javaAPI DocExample7782Wed Dec 06 18:55:50 GMT 2000chap4.b2b

Wholesaler

public class Wholesaler extends Object implements javax.jms.MessageListener

Fields Summary
private javax.jms.TopicConnection
connect
private javax.jms.TopicSession
pubSession
private javax.jms.TopicSession
subSession
private javax.jms.TopicPublisher
publisher
private javax.jms.TopicSubscriber
subscriber
private javax.jms.Topic
hotDealsTopic
private javax.jms.TemporaryTopic
buyOrdersTopic
private boolean
topicRequestor
private boolean
requestReplyReceive
Constructors Summary
public Wholesaler(String broker, String username, String password)


         
      try{
        TopicConnectionFactory factory = null;
        InitialContext jndi = null;

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

        factory =
            (TopicConnectionFactory)jndi.lookup("TopicConnectionFactory");

        connect = factory.createTopicConnection (username, password);

        pubSession =
            connect.createTopicSession(false,Session.AUTO_ACKNOWLEDGE);
        subSession =
            connect.createTopicSession(false,Session.AUTO_ACKNOWLEDGE);

        hotDealsTopic = (Topic)jndi.lookup("Hot Deals");

        publisher = pubSession.createPublisher(hotDealsTopic);

        buyOrdersTopic = subSession.createTemporaryTopic();

        subscriber = subSession.createSubscriber(buyOrdersTopic);

        // The printed examples in Chapter 4 cover asynchronous pub/sub, synchronous request/reply using the
        // TopicRequestor object, and synchronous request/reply without the use of the TopicRequestor object.
        // This one example covers all three situations, and has the different functionality bracketed by
        // the use of the "topicRequestor" and "requestReply" booleans.
        // TopicRequestor and receive() do not require a message listener
        if(!topicRequestor && !requestReplyReceive)
            subscriber.setMessageListener(this);

        connect.start();

      }catch (javax.jms.JMSException jmse){
         jmse.printStackTrace(); System.exit(1);
      }catch(javax.naming.NamingException jne){
         jne.printStackTrace(); System.exit(1);
      }
Methods Summary
public voidexit()

      try{
        connect.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 Wholesaler broker username password");
         return;
      }

      Wholesaler wholesaler = new Wholesaler(broker, username, password);

      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 ) );
         System.out.println ("Enter: Item, Old Price, New Price ");
         System.out.println("\ne.g. Bowling Shoes, 100.00, 55.00");

         while ( true ){
            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();

               wholesaler.publishPriceQuotes(dealDesc,username,
                                             itemDesc, oldPrice,newPrice);
            }else{
                wholesaler.exit();
            }
         }
      }catch( java.io.IOException ioe ){
         ioe.printStackTrace();
      }
public voidonMessage(javax.jms.Message message)

      try{
         TextMessage textMessage = (TextMessage) message;
         String text = textMessage.getText();
         System.out.println("\nOrder received - "+text+
                            " from " + message.getJMSCorrelationID());
      }catch (java.lang.Exception rte){
         rte.printStackTrace();
      }
private voidpublishPriceQuotes(java.lang.String dealDesc, java.lang.String username, java.lang.String itemDesc, float oldPrice, float newPrice)

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

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

        message.setJMSReplyTo(buyOrdersTopic);

        // The printed examples in Chapter 4 cover asynchronous pub/sub, synchronous request/reply using the
        // TopicRequestor object, and synchronous request/reply without the use of the TopicRequestor object.
        // This one example covers all three situations, and has the different functionality bracketed by
        // the use of the "topicRequestor" and "requestReply" booleans.
        if(topicRequestor)
        {
            //System.out.println("\nInitiating Synchronous Request");
            javax.jms.TopicRequestor requestor =
                new javax.jms.TopicRequestor(pubSession, hotDealsTopic);
            javax.jms.Message aMessage = requestor.request(message);
            if (aMessage == null)
                System.out.println("\nrequest() returned null");
            else
                System.out.println("\nRequest Sent, Reply Received!");
            if (aMessage != null)
            {
                onMessage(aMessage);
            }
            return;
        }

        // Publish the message.  If its an asynchronous pub/sub, the onMessage handler
        // will get called automatically
        // If its a synchronous request/reply via receive(), call onMessage directly
        publisher.publish(
            message,
            javax.jms.DeliveryMode.PERSISTENT,
            javax.jms.Message.DEFAULT_PRIORITY,
            1800000);

        if(requestReplyReceive)
        {
            javax.jms.Message aMessage = subscriber.receive();
            if (aMessage == null)
                System.out.println("\nreceive() returned null");
            else
                System.out.println("\nRequest Sent, Reply Received!");

            if (aMessage != null)
            {
                onMessage(aMessage);
            }
            return;
        }
      }catch ( javax.jms.JMSException jmse ){
         jmse.printStackTrace();
      }