The JMS 2.0 aka simplified API has reduced the number of JMS objects required to send a message to a destination. The simplified API provides two objects for the said task, JMSProducer and JMSConsumer interfaces respectively. The good thing about them is they both allow method calls to be chained together.
Let's take a look at the sender code.
public void sendMessage(String messageText, String destinationAddress){
ResourceFactory resourceFactory = new ResourceFactoryImpl();
try(JMSContext jmsContext = resourceFactory.getJMSContext(JMSContext.AUTO_ACKNOWLEDGE);){
Queue queue = jmsContext.createQueue(destinationAddress);
jmsContext.createProducer().send(queue, messageText);
}
}
A word on JMSContext.createQueue(String queueAddress)
The JMSContext.createQueue(String queueAddress) would not create a physical destination but Queue object for an existing destination. It is encouraged to look up for the administrative Queue object on the JNDI namespace since this approach reduces the chances of portability of the code as we have to provide it with a vendor specific physical Queue name.
However, in this example, it's required to provide this method with the physical queue name. In HornetQ, it's the queue address name.
On a side note, the JMS API does not provide a mechanism to create permanent destinations. It's up to the JMS implementation to provide a mechanism to create permanent destination(s). This is not mandatory since JMS specification doesn't impose JMS providers to implement such a feature.
However the JMS API allows the creation of temporary destinations. The temporary destination(s) would be removed and garbage collected when the JMS Session/JMSContext associated with the temporary destination gets closed.
The JMS receiver code is pretty simple too. One thing you would notice is the ease of obtaining the message payload using JMSConsumer.receiveBody(), without performing any typecasting as it was with the JMS 1.1 specification. Here's the receiver code :
public String receiveTextMessage(String destinationAddress){
ResourceFactory resourceFactory = new ResourceFactoryImpl();
try(JMSContext jmsContext = resourceFactory.getJMSContext(JMSContext.AUTO_ACKNOWLEDGE);){
Queue queue = jmsContext.createQueue(destinationAddress);
JMSConsumer jmsConsumer = jmsContext.createConsumer(queue);
return jmsConsumer.receiveBody(String.class);
}
}
The ResourceFactory helper interface and its implementation excerpt :
public interface ResourceFactory {
public ConnectionFactory getConnectionFactory();
public JMSContext getJMSContext(int sessionTx);
}
public class ResourceFactoryImpl implements ResourceFactory {
....
....
@Override
public JMSContext getJMSContext(int sessionTx) {
ConnectionFactory connectionFactory = getConnectionFactory();
JMSContext jmsContext = connectionFactory.createContext(JMSHelper.getProperty("jms.user.name"), JMSHelper.getProperty("jms.user.password"),sessionTx);
return jmsContext;
}
....
....
}
