Queue.scala

package queue

import akka.actor.{Actor, Props}
import queue.ActorWithQueue._

class ActorWithQueue(init: Queue[String] = Queue.empty ) extends Actor {

  def handleMessage(queue: Queue[String]): Receive = {
    case Push(str) =>
      handleMessage(queue.enqueue(str))
    case Pull =>
      queue.dequeueOption match {
        case Some((str, q)) =>
          sender ! Elem(str)
          context.become(handleMessage(q))
        case None =>
          sender ! EmptyQueue
      }
  }


  override def receive: Receive = handleMessage(init)
}

object ActorWithQueue {
  def props() = Props(new ActorWithQueue)

  case class Push(str: String)
  case object Pull

  case class Elem(str: String)
  case object EmptyQueue
}