Actor Callbacks

class Callback(f: => Unit) {
   def apply() : Unit = f
}

trait CallbackHandler {
  self : Actor =>

  def handleCallback : Receive = {
    case callback: Callback =>
      callback()
  }

  override def unhandled(msg : Any) :Unit = {
     handleCallback.applyOrElse(msg, super.unhandled)
  }

  def onSuccess(fut: Future[T])(f : T => Unit) : Unit = {
  fut.onSuccess {
    t => self ! new Callback(f(t))
  }
 }
}