ChildActorExercise.scala

package playground

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

object ChildActorExercise extends App {

  object WordCountMaster {
    case class Initialize(workersCount: Int)
    case class WordCountTask(origin: ActorRef, text: String)
    case class WordCountReply(origin: ActorRef, count: Int)
  }
  class WordCountMaster extends Actor {

    def mainLoop(workersIterator: Iterator[ActorRef]): Receive = {
      case text: String =>
        workersIterator.next() ! WordCountMaster.WordCountTask(sender(), text)
      case WordCountMaster.WordCountReply(origin, count) =>
        println(s"${self.path}: Count: $count")
        origin ! count
    }

    override def receive: Receive = {
      case WordCountMaster.Initialize(count) =>
        val listOfActors =
          for (c <- 1 to count) yield context.actorOf(Props[WordCountWorker], s"worker$c")

        context.become(mainLoop(Iterator.continually(listOfActors).flatten))
    }
  }

  class WordCountWorker extends Actor {
    override def receive: Receive = {
      case WordCountMaster.WordCountTask(origin, text) =>
        println(s"${self.path}: I've got a message: $text")
        sender() ! WordCountMaster.WordCountReply(origin, text.split(" ").length)
    }
  }

  val system = ActorSystem.create("wordCountMaster")
  val master = system.actorOf(Props[WordCountMaster], "master")

  master ! WordCountMaster.Initialize(3)
  master ! "Hello, World!"
  master ! "Lorem ispum dorem"
  master ! "There is some apples..."
  master ! "Quick brown fox jumped over the..."
}