Sending messages to your Akka Actors from JMX

Lately I was a bit busy learning new technologies like Scala, Akka and changing my mind to start to think in functional way. As I promised, my next posts will be about Scala and all technologies related to this language.

 Today I want to show you how to combine an old friend like JMX with and application done with Akka. Scala runs on the JVM so you have all the tools available in the Java platform. To follow this tutorial, it is necessary to have an idea about what does it means the Actor Model

Also you need to have installed Scala. Please follow this instructions if you don't have any installation. I recommend to you IntelliJ as a development environment, it provides a cool support to work with Scala.

Cool! We are ready to start. Our application is very simple, we are going to create an Actor called Pong, and this actor will be waiting a message from a JMX client. This client will be able to send messages to our actor Pong. If the message sent is "end", Pong will be terminated. Otherwise the message will be stored in memory. From our JMX client, we can ask for the last message received by the actor Pong. Let's see some code.

First of all , our support to code actors with JMX support. Extending this trait the actor will be registered in our MBeanServer automatically using the methods preStart and postStop. Note that method getMXTypeName is an abstract method and is implemented by the child class.

Is time to define our MBean. By convention the MBean is defined with the suffix MBean. Here is the trait that exposes the operations available from our MBean.


Finally the actor Pong implements the trait showed above and extends from our ActorWithJMXSupport.

Then we need a main application to start up the actor Pong.

Ok! The hard work is done. Now you have to start your application passing to the JVM this parameters:

-Dcom.sun.management.jmxremote 
-Dcom.sun.management.jmxremote.port=1617 
-Dcom.sun.management.jmxremote.authenticate=false 
-Dcom.sun.management.jmxremote.ssl=false

At this point, you have the application running with the actor Pong waiting for requests. As you can see the MBean server is listening in port 1617.

Finally executing jmc in a console, the JMX client provided by the jdk, will be opened. Then you can browse in the MBean browser to find our MBean registered. In the tab operations, you can execute the operations defined by the PongMBean. In the next video, you can see this last part clearly.