JmsActor.scala

class JmsManagerActor(messageParser: MessageParser) extends Actor {

  def receive: Receive = {
    case SubscribeForMessage(id) if isAlreadyReceived(id) =>
      msgsBuffer.remove(id)
      sender ! Ack

    case SubscribeForMessage(id) =>
      subscriptionMap.update(id, sender())

    case NewMessage(message) =>
      val id = messageParser.parse(message)

      if (isSomeOneWaiting(id)) {
        val waiter = subscriptionMap.remove(id).get
        waiter ! Ack
      } else {
        msgsBuffer += id
      }
  }
  //...
}