Akka is an excellent platform for writing concurrent applications using the Actor model. Chariot architect Anatoly Polinsky describes the Akka scheduler and how you can use it to create a heartbeat for an actor. From Anatoly's blog:
AKKA Scheduler: Sending Message to Actor’s Self on Start
Akka has a little scheduler written using actors. This can be convenient if you want to schedule some periodic task for maintenance or similar. It allows you to register a message that you want to be sent to a specific actor at a periodic interval.
How Does AKKA Schedule Things?
Behind the scenes, AKKA scheduler relies on “ScheduledExecutorService” from the “java.util.concurrent” package. Hence when AKKA Scheduler needs to schedule “a message sent to an actor, given a certain initial delay and interval”, it just wraps the task of sending a message in a “java.lang.Runnable”, and uses a “ScheduledExecutorService” to schedule it:
service. scheduleAtFixedRate ( createSendRunnable( receiver, message, true ),
initialDelay, delay, timeUnit).asInstanceOf[ScheduledFuture[AnyRef]]