messageheaderstopic.java

JMS的例子程序

                try {
                    SampleUtilities.sendSynchronizeMessage("SUBSCRIBER THREAD: ",
                                                            CONTROL_QUEUE);
                } catch (Exception e) {
                    System.out.println("Queue probably missing: " + e.toString());
                    if (topicConnection != null) {
                        try {
                            topicConnection.close();
                        } catch (JMSException ee) {}
                    }
    	            System.exit(1);
    	        }

                for (int i = 0; i < 3; i++) {
                    message = (TextMessage) topicSubscriber.receive();
                    System.out.println("\nSUBSCRIBER THREAD: Message received: " 
                        + message.getText());
                    System.out.println("SUBSCRIBER THREAD: Headers after message is received:");
                    displayHeaders(message, "SUBSCRIBER THREAD: ");
                }
            } catch (JMSException e) {
                System.out.println("Exception occurred: " + e.toString());
                exitResult = 1;
            } finally {
                if (topicConnection != null) {
                    try {
                        topicConnection.close();
                    } catch (JMSException e) {
                        exitResult = 1;
                    }
                }
            }   	    
        }
    }
    
    /**
     * Displays all message headers.  Each display is in a try/catch block in
     * case the header is not set before the message is published.
     *
     * @param message	the message whose headers are to be displayed
     * @param prefix	the prefix (publisher or subscriber) to be displayed
     */
    public void displayHeaders (Message message, String prefix) {
        Destination  dest = null;      
        int          delMode = 0;
        long         expiration = 0;
        Time         expTime = null;
        int          priority = 0;
        String       msgID = null;
        long         timestamp = 0;
        Time         timestampTime = null;
        String       correlID = null;
        Destination  replyTo = null;
        boolean      redelivered = false;
        String       type = null;
        String       propertyName = null;
        
        try {
            System.out.println(prefix + "Headers set by publish/send method: ");
            
            // Display the destination (topic, in this case).
            try {
                dest = message.getJMSDestination();
                System.out.println(prefix + " JMSDestination: " + dest);
            } catch (Exception e) {
                System.out.println(prefix + "Exception occurred: " 
                    + e.toString());
                exitResult = 1;
            }
            
            // Display the delivery mode.
            try {
                delMode = message.getJMSDeliveryMode();
                System.out.print(prefix);
                if (delMode == DeliveryMode.NON_PERSISTENT) {
                    System.out.println(" JMSDeliveryMode: non-persistent");
                } else if (delMode == DeliveryMode.PERSISTENT) {
                    System.out.println(" JMSDeliveryMode: persistent");
                } else {
                    System.out.println(" JMSDeliveryMode: neither persistent nor non-persistent; error");
                }
            } catch (Exception e) {
                System.out.println(prefix + "Exception occurred: " 
                    + e.toString());
                exitResult = 1;
            }
            
            /*
             * Display the expiration time.  If value is 0 (the default),
             * the message never expires.  Otherwise, cast the value
             * to a Time object for display.
             */
            try {
                expiration = message.getJMSExpiration();
                System.out.print(prefix);
                if (expiration != 0) {
                    expTime = new Time(expiration);
                    System.out.println(" JMSExpiration: " + expTime);
                } else {
                    System.out.println(" JMSExpiration: " + expiration);
                }
            } catch (Exception e) {
                System.out.println(prefix + "Exception occurred: " 
                    + e.toString());
                exitResult = 1;
            }
            
            // Display the priority.
            try {
                priority = message.getJMSPriority();
                System.out.println(prefix + " JMSPriority: " + priority);
            } catch (Exception e) {
                System.out.println(prefix + "Exception occurred: " 
                    + e.toString());
                exitResult = 1;
            }
            
            // Display the message ID.
            try {
                msgID = message.getJMSMessageID();
                System.out.println(prefix + " JMSMessageID: " + msgID);
            } catch (Exception e) {
                System.out.println(prefix + "Exception occurred: " 
                    + e.toString());
                exitResult = 1;
            }
            
            /*
             * Display the timestamp.
             * If value is not 0, cast it to a Time object for display.
             */
            try {
                timestamp = message.getJMSTimestamp();
                System.out.print(prefix);
                if (timestamp != 0) {
                    timestampTime = new Time(timestamp);
                    System.out.println(" JMSTimestamp: " + timestampTime);
                } else {
                    System.out.println(" JMSTimestamp: " + timestamp);
                }
            } catch (Exception e) {
                System.out.println(prefix + "Exception occurred: " 
                    + e.toString());
                exitResult = 1;
            }
            
            // Display the correlation ID.
            try {
                correlID = message.getJMSCorrelationID();
                System.out.println(prefix + " JMSCorrelationID: " + correlID);
            } catch (Exception e) {
                System.out.println(prefix + "Exception occurred: " 
                    + e.toString());
                exitResult = 1;
            }
            
           // Display the ReplyTo destination.
           try {
                replyTo = message.getJMSReplyTo();
                System.out.println(prefix + " JMSReplyTo: " + replyTo);
            } catch (Exception e) {
                System.out.println(prefix + "Exception occurred: " 
                    + e.toString());
                exitResult = 1;
            }
            
            // Display the Redelivered value (usually false).
            System.out.println(prefix + "Header set by JMS provider:");
            try {
                redelivered = message.getJMSRedelivered();
                System.out.println(prefix + " JMSRedelivered: " + redelivered);
            } catch (Exception e) {
                System.out.println(prefix + "Exception occurred: " 
                    + e.toString());
                exitResult = 1;
            }
            
            // Display the JMSType.
            System.out.println(prefix + "Headers set by client program:");
            try {
                type = message.getJMSType();
                System.out.println(prefix + " JMSType: " + type);
            } catch (Exception e) {
                System.out.println(prefix + "Exception occurred: " 
                    + e.toString());
                exitResult = 1;
            }
            
            // Display any client properties.
            try {
                for (Enumeration e = message.getPropertyNames(); e.hasMoreElements() ;) {
                    propertyName = new String((String) e.nextElement());
                    System.out.println(prefix + " Client property " 
                        + propertyName + ": " 
                        + message.getObjectProperty(propertyName)); 
                }
            } catch (Exception e) {
                System.out.println(prefix + "Exception occurred: " 
                    + e.toString());
                exitResult = 1;
            }
        } catch (Exception e) {
                System.out.println(prefix + "Exception occurred: " 
                    + e.toString());
            exitResult = 1;
        }
    }

    /**
     * Instantiates the subscriber and publisher classes and starts their
     * threads.
     * Calls the join method to wait for the threads to die.
     * <p>
     * It is essential to start the subscriber before starting the publisher.
     * In the publish/subscribe model, a subscriber can ordinarily receive only 
     * messages published while it is active.
     */
    public void run_threads() {
        HeaderSubscriber  headerSubscriber = new HeaderSubscriber();
        HeaderPublisher   headerPublisher = new HeaderPublisher();

        headerSubscriber.start();
        headerPublisher.start();
        try {
            headerSubscriber.join();
            headerPublisher.join();
        } catch (InterruptedException e) {}
    }
    
    /**
     * Reads the topic name from the command line, then calls the
     * run_threads method to execute the program threads.
     *
     * @param args	the topic used by the example
     */
    public static void main(String[] args) {
        MessageHeadersTopic  mht = new MessageHeadersTopic();

        if (args.length != 1) {
    	    System.out.println("Usage: java MessageHeadersTopic <topic_name>");
    	    System.exit(1);
    	}
        mht.topicName = new String(args[0]);
        System.out.println("Topic name is " + mht.topicName);

    	mht.run_threads();
    	SampleUtilities.exit(mht.exitResult); 
    }
}