Stackable trait with context.become

Main.scala

package stackable

import akka.actor.{Props, ActorSystem, Actor}

object Main extends App {
  val sys = ActorSystem("stackable")
  val act = sys.actorOf(Props[EchoActor])

  act ! "BooHoo"
  act ! "BooHoo"
  act ! "BooHoo"

  System.in.read()

  sys.shutdown()
  sys.awaitTermination()
}

trait Behaviour { self: Actor =>
  var wrapped: Receive = _

  def receive: Receive = {
    case msg => if (wrapped.isDefinedAt(msg)) wrapped(msg) else unhandled(msg)
  }
}

trait FunnyTracer extends Behaviour { self: Actor =>
  override def receive = {
    case msg =>
      println("Mooo!")
      super.receive(msg)
      println("Oink oink!")
  }
}

class EchoActor extends Actor with FunnyTracer {

  def statefulReceive: Int => Receive = (i: Int) => {
    case msg =>
      println(s"Received $msg while storing $i")
      wrappedBecome(statefulReceive(i+1))
  }

  def wrappedBecome(r: Receive) = {
    wrapped = r
  }

  wrappedBecome(statefulReceive(0))
}

terminal

> sbt run
Mooo!
Received BooHoo while storing 0
Oink oink!
Mooo!
Received BooHoo while storing 1
Oink oink!
Mooo!
Received BooHoo while storing 2
Oink oink!