[WSO2][ESB] Class mediator sample

Hi all,

Here I present sample class mediator which I used in JMS local transactions. You can download relevant dependency jars thorough following links:

Dependency jars:

•  Synapse core - http://www.java2s.com/Code/JarDownload/synapse/synapse-core-2.1.0.jar.zip
•  Apache axiom - http://www.java2s.com/Code/JarDownload/apache-axiom/apache-axiom-api-1.2.7.jar.zip 

 package org.wso2.carbon.mediator;  
 import org.apache.synapse.MessageContext;  
 import org.apache.synapse.mediators.AbstractMediator;  
 /**  
  * This class counting messages received and use as class mediator
  */  
 public class MessageCounterMediator extends AbstractMediator {  
     private static int MESSAGE_COUNT = 0;  
     public boolean mediate(MessageContext synCtx) {  
       MESSAGE_COUNT++;  
       synCtx.setProperty("MESSAGE_COUNT", MESSAGE_COUNT);  
       return true;  
     }  
 }  

For more information, refer https://docs.wso2.com/display/ESB470/Sample+380%3A+Writing+your+own+Custom+Mediation+in+Java

You can write own java classes and use them within WSO2 ESB. :) :)

HornetQ JMS Subscriber

Hi all,

HornetQ is a JMS broker which is support JMS 2.0 specification. Here you can find a JMS subscriber written for queue within HornetQ.

 import javax.jms.*;  
 import javax.naming.Context;  
 import javax.naming.InitialContext;  
 import java.util.Properties;  
 /**  
  * This is a hornetq subscriber java class for a queue  
  */  
 public class HornetQSubscriber {  
   private static final String DEFAULT_CONNECTION_FACTORY = "QueueConnectionFactory";  //TopicConnectionFactory when using for topics
   private static final String DEFAULT_DESTINATION = "queue/mySampleQueue";  //Can change when it is a topic
   private static final String INITIAL_CONTEXT_FACTORY = "org.jnp.interfaces.NamingContextFactory";  
   private static final String PROVIDER_URL = "jnp://localhost:1099";  
   public static void main(final String[] args) {  
     try {  
       runExample();  
     } catch (Exception e) {  
       e.printStackTrace();  
     }  
   }  
   public static void runExample() throws Exception {  
     Connection connection = null;  
     Context initialContext = null;  
     try {  
       // /Step 1. Create an initial context to perform the JNDI lookup.  
       final Properties env = new Properties();  
       env.put(Context.INITIAL_CONTEXT_FACTORY, INITIAL_CONTEXT_FACTORY);  
       env.put(Context.PROVIDER_URL, System.getProperty(Context.PROVIDER_URL, PROVIDER_URL));  
       initialContext = new InitialContext(env);  
       // Step 2. perform a lookup on the Queue  
       Queue queue = (Queue) initialContext.lookup(DEFAULT_DESTINATION);  
       // Step 3. perform a lookup on the Connection Factory  
       ConnectionFactory cf =  
           (ConnectionFactory) initialContext.lookup(DEFAULT_CONNECTION_FACTORY);  
       // Step 4. Create a JMS Connection  
       connection = cf.createConnection();  
       // Step 5. Create a JMS Session  
       Session session = connection.createSession(false, Session.CLIENT_ACKNOWLEDGE);  
       // Step 6. Create a JMS Message Consumer  
       MessageConsumer messageConsumer =  
           session.createConsumer(queue);  
       // Step 7. Start the Connection  
       connection.start();  
       System.out.println("Message consumer started on Queue: " + DEFAULT_DESTINATION +  
           "\n");  
       // Step 8. Receive the message  
       int message_count=0;  
       while (messageConsumer.receive()!=null) {  
         message_count++;  
         System.out.println("Received a message ------------"+message_count);  
       }  
     } finally {  
       // Step 9. Close JMS resources  
       if (connection != null) {  
         connection.close();  
       }  
       // Also the initialContext  
       if (initialContext != null) {  
         initialContext.close();  
       }  
     }  
   }  
 }  

* Note : you can modify class when you are going to publish JMS messages to topics. Relevant places are highlighted within the class.

How to write a JMS publisher for queue in WSO2 MB ?

Hello all,

We are gonna write a JMS publisher for queue WSO2 MB. Let's begin ...

Prerequisites:

• WSO2 MB pack should be downloaded.
• MB should be up and running (You can follow WSO2 MB documentation, if you are not familiar with MB) 
• Java should be installed (As we implement JMS publisher as a Java Class)

Environment used:

• Oracle jdk 1.8
• MB 3.1.0
• IDEA as 

JMS Publisher class:

 import javax.jms.*;  
 import javax.naming.Context;  
 import javax.naming.InitialContext;  
 import javax.naming.NamingException;  
 import java.util.Properties;  
 /**  
  * This class will publish messages to MB Queue  
  */  
 public class QueuePublisher {  
   public static final String QPID_ICF = "org.wso2.andes.jndi.PropertiesFileInitialContextFactory";  
   private static final String CF_NAME_PREFIX = "connectionfactory.";  
   private static final String QUEUE_NAME_PREFIX = "queue.";  
   private static final String CF_NAME = "qpidConnectionfactory";  
   String userName = "admin";  
   String password = "admin";  
   private static String CARBON_CLIENT_ID = "carbon";  
   private static String CARBON_VIRTUAL_HOST_NAME = "carbon";  
   private static String CARBON_DEFAULT_HOSTNAME = "localhost";  
   private static String CARBON_DEFAULT_PORT = "5672";  
   String queueName = "JMSProxy";  //Change this with relevant queue name
   int publishMsgCount=5;  
   public static void main(String[] args) throws NamingException, JMSException {  
     QueuePublisher queueSender = new QueuePublisher();  
     queueSender.sendMessages();  
   }  
   public void sendMessages() throws NamingException, JMSException {  
     Properties properties = new Properties();  
     properties.put(Context.INITIAL_CONTEXT_FACTORY, QPID_ICF);  
     properties.put(CF_NAME_PREFIX + CF_NAME, getTCPConnectionURL(userName, password));  
     properties.put(QUEUE_NAME_PREFIX + queueName, queueName);  
     Properties properties2 = new Properties();  
     properties2.put(Context.INITIAL_CONTEXT_FACTORY, QPID_ICF);  
     properties2.put(CF_NAME_PREFIX + CF_NAME, getTCPConnectionURL(userName, password));  
     System.out.println("getTCPConnectionURL(userName,password) = " + getTCPConnectionURL(userName, password));  
     InitialContext ctx = new InitialContext(properties);  
     // Lookup connection factory  
     QueueConnectionFactory connFactory = (QueueConnectionFactory) ctx.lookup(CF_NAME);  
     QueueConnection queueConnection = connFactory.createQueueConnection();  
     queueConnection.start();  
     QueueSession queueSession = queueConnection.createQueueSession(false,QueueSession.AUTO_ACKNOWLEDGE );//  
     Queue queue = (Queue)ctx.lookup(queueName);  
     javax.jms.QueueSender queueSender = queueSession.createSender(queue);  
     //sending 5 messages to the above created queue here  
     for(Integer i=1;i<=publishMsgCount;i=i+1){  
       TextMessage textMessage = queueSession.createTextMessage("::::Test Message:::: "+i+":::Publish to queue:::"+queueName+":::From IP:::"+CARBON_DEFAULT_HOSTNAME);  
       textMessage.setStringProperty("msgID", i.toString());  
       queueSender.send(textMessage);  
       System.out.println("Publishing Test Message "+i+"::Published From IP::"+CARBON_DEFAULT_HOSTNAME);  
     }  
     queueSender.close();  
     queueSession.close();  
     queueConnection.close();  
   }  
   public String getTCPConnectionURL(String username, String password) {  
     // amqp://{username}:{password}@carbon/carbon?brokerlist='tcp://{hostname}:{port}'  
     return new StringBuffer()  
         .append("amqp://").append(username).append(":").append(password)  
         .append("@").append(CARBON_CLIENT_ID)  
         .append("/").append(CARBON_VIRTUAL_HOST_NAME)  
         .append("?brokerlist='tcp://").append(CARBON_DEFAULT_HOSTNAME).append(":").append(CARBON_DEFAULT_PORT).append("'")  
         .toString();  
   }  
 }  

** For this java class you have to add client libraries as dependencies. You can find relevant jars from $MB_HOME/client-lib/

Add all these jars as dependencies.

• andes-client-3.1.1.jar
• geronimo-jms_1.1_spec-1.1.0.wso2v1.jar
• log4j-1.2.13.jar
• org.wso2.carbon.logging-4.4.1.jar
• org.wso2.securevault-1.0.0-wso2v2.jar
• slf4j-1.5.10.wso2v1.jar

You are successfully done with JMS publisher. Add a queue in MB which you want to publish messages and add that name in the JMS publisher class.

(Note: In here I used "JMSProxy" queue to publish messages.)