Actor Example ping-pong

actor.scala

import scala.actors.Actor

object Main {
  def main(args: Array[String]): Unit = {
    val pong = new Pong
    val ping = new Ping(100000, pong)
    ping.start
    pong.start
  }
}

case object Ping
case object Pong
case object Stop


class Ping(count: Int, pong: Actor) extends Actor {
  def act() {
    var pingsLeft = count - 1
    pong ! Ping
    while(true) {
      receive {
        case Pong => {
          if (pingsLeft % 1000 == 0) println("Ping : pong")
          if (pingsLeft > 0) {
            pong ! Ping
            pingsLeft -= 1
          } else {
            println("Ping : stop")
            pong ! Stop
            exit()
          }
        }
      }
    }
  }
}

class Pong extends Actor {
  def act() {
    var pongCount = 0
    while(true){
      receive {
        case Ping => {
          if (pongCount % 1000 == 0) println("Pong : ping " + pongCount)
          sender ! Pong
          pongCount += 1
        }
        case Stop => {
          println("Pong : stop")
          exit()
        }
      }
    }

  }
}