Consumer Code Example

This code connects to the UH Message Broker and consumes the messages described in UHIMS Events

1. Download the RabbitMQ Java client from http://www.rabbitmq.com/download.html (there should be libraries and examples for other languages there)
2. Here is a SampleUhimsConsumer.java you can try.
   • Replace the following with your own values:
     • yourRabbitMqUsernameHere
     • yourRabbitMqPasswordHere
     • yourQueueNameHere

     • esb-test.its.hawaii.edu with esb.hawaii.edu when your code is ready to use the production RabbitMQ service.

       import java.io.*;
       import java.security.*;
       import com.rabbitmq.client.*;
       
       public class SampleUhimsConsumer {
       
           private final static  String queueName    = "yourQueueNameHere";
           private final static boolean durable       = true;
           private final static boolean exclusive     = true;
           private final static boolean autoDelete    = false;
           private final static boolean autoAck       = false;     // we will ack each message ourselves
           private final static    long timeout       = 2*60*1000; // to exit after 2 minutes without messages
       
        public static void main(String[] argv) throws Exception {
       
           ConnectionFactory factory = new ConnectionFactory();
       
           factory.setHost("esb-test.its.hawaii.edu");
           factory.setPort(5671);
           factory.setVirtualHost("uhims");
           factory.setUsername("yourRabbitMqUsernameHere");
           factory.setPassword("yourRabbitMqPasswordHere");
       
           factory.useSslProtocol(); // Tells the library to setup the default Key and Trust managers for you
                                     // which do not do any form of remote server trust verification
       
           Connection conn       = factory.newConnection();
           Channel    channel    = conn.createChannel();
           System.out.println(" [*] Waiting for messages. To exit press CTRL+C");
           QueueingConsumer consumer = new QueueingConsumer(channel);
           channel.basicConsume(queueName, autoAck, consumer);
       
           while (true) {
             QueueingConsumer.Delivery delivery = consumer.nextDelivery(timeout);
             if (delivery == null) {
               // stop consumer if no events arrive after timeout milliseconds
               conn.close();
             }
             else {
               // Your code processes the message here
               String message = new String(delivery.getBody());
               System.out.println(" [x] Received '" + message + "'");
       
               // If your code fails to acknowledge the message,
               // it will be redelivered.  This is a safety feature.
               // Refer to Message Acknowledgement section in
               // http://www.rabbitmq.com/tutorials/tutorial-two-java.html
       
               channel.basicAck(delivery.getEnvelope().getDeliveryTag(), false);
             }
           }
         }
       }
       

3. To quickly compile and run the above, you could save the above code as SampleUhimsConsumer.java in the same directory where you downloaded the above Java client (we tried it with rabbitmq-java-client-bin-2.7.1):
   • javac -cp rabbitmq-client.jar SampleUhimsConsumer.java
   • java -cp .:commons-io-1.2.jar:commons-cli-1.1.jar:rabbitmq-client.jar SampleUhimsConsumer
4. That's it!

See Download page for more complete code examples.
Javadoc at http://www.rabbitmq.com/javadoc/