1.1 Install the plugin

grails install-plugin jms

1.2 Creating a Connection Factory

The use of the JMS Plugin requires that you have a bean named connectionFactory defined in grails-app/conf/spring/resources.xml. See your broker's documentation for instructions for how to do this. For example, using ActiveMQ's default configuration:

<bean id="connectionFactory" class="org.apache.activemq.ActiveMQConnectionFactory">
    <property name="brokerURL" value="tcp://localhost:61616" />
</bean>

2.1 Exposing your Service

To expose your service as an MDP, you need to create a message listener closure or method. By default, this needs to be called onMessage, although you can override this as we'll see below. Once you've defined your message listener, simply add a static property called expose and set it to a list containing 'jms'. For example:

class SampleQueueService {
    static expose = ['jms']

    def onMessage = {
       println "GOT MESSAGE: $it"
    }

}

If you define onMessage as a method, that'll work too:

class SampleQueueService {
    static expose = ['jms']

    def onMessage(messageObject) {
       println "GOT MESSAGE: $messageObject"
    }

}

By default, this will attach this service as a message listener to a JMS Queue named sampleQueue

XFire/Remoting Compatibility You may notice that the configuration is similar to that for the XFire and Remoting plugin.

2.2 Additional Configuration

There are a number of configuration changes you can make by setting various static properties on your service class:

3 Sending JMS Messages

As of version 0.2 of the plugin, Service and Controller artefacts have these closures defined:

• sendQueueJMSMessage & sendJMSMessage - send messages to a Queue destination
• sendJMSMessage & sendPubSubJMSMessage - send messages to a Topic destination
  
  All closures take two parameters: the destination name and the message. For example, here's a save action closure that sends a JMS message upon entity creation:

  def save = {
      def blogEntry = new BlogEntry(params)
      if(!blogEntry.hasErrors() && blogEntry.save()) {
          flash.message = "BlogEntry ${blogEntry.id} created"
          sendJMSMessage("sample", "Blog Entry entitled ${blogEntry.title} has been created.")
          redirect(action:show,id:blogEntry.id)
      }
      else {
          render(view:'create',model:[blogEntry:blogEntry])
      }
  }

Active MQ

1. Download ActiveMQ from http://activemq.apache.org/
2. Add activemq-core-4.1.1.jar, backport-util-concurrent-3.0.jar, geronimo-j2ee-management_1.0_spec-1.0.jar, and geronimo-jms_1.1_spec-1.0.jar from the ActiveMQ distribution into the lib directory of your Grails application.
3. Add this to your conf/spring/resources.xml changing the brokerURL based on your ActiveMQ configuration:

   <bean id="connectionFactory" class="org.apache.activemq.ActiveMQConnectionFactory">
       <property name="brokerURL" value="tcp://localhost:61616"/>
   </bean>

4. Start ActiveMQ

JBossMQ (running inside JBossAS)

This applies to Grails applications deployed inside JBossAS.

1. Download JBossAS from http://labs.jboss.com/jbossas/
2. Add this to your conf/spring/resources.xml:

   <bean id="connectionFactory" class="org.springframework.jndi.JndiObjectFactoryBean">
   		<property name="jndiName" value="java:/ConnectionFactory"/>
   	</bean>

JBossMQ (running outside JBossAS)

This applies to Grails application deployed outside JBossAS or in a separate JBossAS instance from the one running JBossMQ.

1. Download JBossAS from http://labs.jboss.com/jbossas/
2. Add jbossall-client.jar (from JBOSS_HOME/client) to the lib directory of your Grails application
3. Add this to your conf/spring/resources.xml:

   <bean id="connectionFactory" class="org.springframework.jndi.JndiObjectFactoryBean">
   		<property name="jndiName" value="ConnectionFactory" />
   		<property name="jndiEnvironment">
   			<props>
   				<prop key="java.naming.factory.initial">org.jnp.interfaces.NamingContextFactory</prop>
   				<prop key="java.naming.provider.url">localhost:1099</prop>
   			</props>
   		</property>
   	</bean>