Coding Tips for Messaging

by Senthil Krishnamurhty from Aspire Systems (India) Pvt. Ltd.

 

 

This article will give you some tips about JMS and MSMQ configurations, with some coding examples.

 

JMS Example :

 

Step 1: Configuring JMS in Jdeveloper OC4J

1.       Open the jms.xml file, which is in the config directory of Jdeveloper home path.

2.       Insert the following lines if they are not present in the file

                              <!-- This will create a QueueConnectionFactory and a queue. Following are the java coding samples for JMS -->

                              <queue-connection-factory location="jms/OracleSyndicateQueueConnectionFactory" listener-threads="3"/>

                               <queue name="jms/OracleSyndicateQueue" location="jms/OracleSyndicateQueue" listener-threads="3">

                               <description>Oracle Syndication Services Queue</description>

                               </queue>

 

 

Step 2: Set JNDI properties

 

                               // This will lookup JMS resource in JMS Server.

                               InitialContext jndi = null;

                               Properties env = new Properties();

                               env.put(Context.SECURITY_PRINCIPAL, "admin");

                               env.put(Context.SECURITY_CREDENTIALS, "admin");

                               env.put(Context.INITIAL_CONTEXT_FACTORY,"com.evermind.server.rmi.RMIInitialContextFactory");

                               env.put(Context.PROVIDER_URL, "ormi://localhost:23791");  //Specify JMS Server URL

                               env.put("dedicated.rmicontext", Boolean.TRUE);

                               jndi = new InitialContext(env);

 

Step 3: JMS Queue setup                                

                               QueueConnectionFactory conFactory = (QueueConnectionFactory) jndi.lookup("jms/OracleSyndicateQueueConnectionFactory");

                               // Create a JMS Queue connection

                               QueueConnection connection = conFactory.createQueueConnection(username, password);

                               // Create two JMS session objects

                               pubSession = connection.createQueueSession(false, Session.AUTO_ACKNOWLEDGE);

                               // Look up a JMS topic

                               Queue chatQueue = (Queue) jndi.lookup("jms/OracleSyndicateQueue");

                               // Create a JMS publisher and subscriber

                               publisher = pubSession.createSender(chatQueue);

                               connection.start();

 

Step 4: Create & Send Message

                               TextMessage message = pubSession.createTextMessage();

                               message.setText("NEWORDER");

                               publisher.send(message);

                               connection.stop();

                               connection.close();

 

Step 5: Receiving JMS Message

 

For receiving messages from JMS server, javax.jms.MessageListener interface must be implemented and onMessage() have to be overloaded which will be called automatically when any new message has arrived to JMS server.

                               // Create Queue Session for subscriber

                               QueueSession subSession = connection.createQueueSession(false,Session.AUTO_ACKNOWLEDGE);

                               // Create a subscriber

                               QueueReceiver subscriber = subSession.createReceiver(chatQueue);

                               // Set a JMS message listener

                               subscriber.setMessageListener(this);

                               connection.start();

                               // onMessage() method. 

                               public void onMessage(Message message) {

                                              TextMessage textMessage = (TextMessage) message;

                                              String text = textMessage.getText();

                                              System.out.println("InComing Message : "+text);

                               }

 

 

MSMQ Example (in C#) :

 

Step 1: Install MSMQ

 

To install MSMQ on a computer running Windows XP or Windows 2000

1.       In Control Panel, double-click Add or Remove Programs.

2.       Click Add/Remove Windows Components.

3.       In Windows XP, select Message Queuing, or in Windows 2000, select Message Queueing Services, click OK, and then click Next.

4.       Click Finish, and then close the Add or Remove Programs window.

 

Step 2: Create Message Queue

 

                              System.Messaging.MessageQueue mq;

                              // Here CSQueue is the queue name.

                              if(MessageQueue.Exists(@".\Private$\CSQueue"))

                              {

                                              mq = new System.Messaging.MessageQueue(@".\Private$\CSQueue");

                              }              

                              else

                              {

                                              mq = MessageQueue.Create(@".\Private$\CSQueue");

                              }

 

Step 3: Send Message

 

                              System.Messaging.Message mm = new System.Messaging.Message();

                              mm.Body = "NEW_ORDER";

                              mm.Label = "OrderMsg";

                              mq.Send(mm);

 

Step 4: Receive Message

 

                              System.Messaging.Message mes = mq.Receive ();

                              mes.Formatter = new XmlMessageFormatter (new String[] {"System.String,mscorlib"});

                              string m = mes.Body.ToString ();

 

 

Conclusion

 

Here we discussed some basic code samples which are needed for configurations and handling messages in both JMS and MSMQ. You can extend these sample coding according to your requirement for the application.