JMS Shared Consumer Example

This example shows you how can use shared consumers to share a subscription on a topic. In JMS 1.1 this was not allowed and so caused a scalability issue. In JMS 2 this restriction has been lifted so you can share the load across different threads and connections.

Example step-by-step

To run the example, simply type mvn verify -Pexample from this directory

1. First we need to get an initial context so we can look-up the JMS connection factory and destination objects from JNDI. This initial context will get it's properties from the client-jndi.properties file in the directory ../common/config

           InitialContext initialContext = getContext();
        

2. We look-up the JMS topic object from JNDI

           Topic topic = (Topic) initialContext.lookup("/topic/exampleTopic");
        

3. We look-up the JMS connection factory object from JNDI

           ConnectionFactory cf = (ConnectionFactory) initialContext.lookup("/ConnectionFactory");
        

4. We create a JMS context

           jmsContext = cf.createContext();
        

5. We create a JMS Producer.

           JMSProducer producer = jmsContext.createProducer();
        

6. We create a shared consumer using the subscription name sc1

          JMSConsumer jmsConsumer = jmsContext.createSharedConsumer(topic, "sc1");
       

7. We then create a second JMS context for a second shared consumer

           jmsContext2 = cf.createContext();
        

8. we then create the second shared consumer using the same subscription name

           JMSConsumer jmsConsumer2 = jmsContext2.createSharedConsumer(topic, "sc1");
        

9. we then send 2 messages

           
           producer.send(topic, "this is a String!");

           producer.send(topic, "this is a second String!") ;
        

10. we then receive the 2 messages using both shared consumers

           
           String body = jmsConsumer.receiveBody(String.class, 5000);

           body = jmsConsumer2.receiveBody(String.class, 5000);
        

11. And finally, always remember to close your JMS connections and resources after use, in a finally block. Closing a JMS connection will automatically close all of its sessions, consumers, producer and browser objects

           finally
           {
              if (initialContext != null)
              {
                 initialContext.close();
              }
              if (jmsContext != null)
              {
                 jmsContext.close();
              }
               if (jmsContext2 != null)
               {
               jmsContext2.close();
               }
           }