import scala.actors.Actor 
import scala.actors.Actor._
import javax.swing.JOptionPane._
import scala.math._

case class Berechnen(f: ((Long, Long) => Long), x: Long, y: Long)

class Prozess(val nr: Int, val f: (Long, Long) => Long, val prozessor: Prozessor) extends Actor {
  val min = 0; val max = 10; val delta = max - min;
  var wertetabelle = List.empty[(Long, Long, Any)]
  
  def act {
    for (i <- 1 to 10) {
      val x = min + (delta * random) round; val y = min + (delta * random) round
      val z = prozessor !! Berechnen(f, x, y)  // Future - Nachricht
      wertetabelle = wertetabelle :+ (x,y,z())
      println("Prozess " + nr + ": f("+x+","+y+") = " + z());  // <-- z ist Future!
    }
    exit  // ... das Ende dieses Prozesses
  }
}

class Prozessor extends Actor {
  start
  
  def act {
    react {
      case Berechnen(f,x,y) => {
        Thread.sleep((50 * math.random).toLong);
        reply( f(x,y) )
      }
      act // Rekursion
    }
  }
}

object Calculator extends Application {
  val functions = List(
    (x: Long, y: Long) => (x + y) * (x - y),
    (x: Long, y: Long) => x*x - y*y,
    (x: Long, y: Long) => x*x + y*y,
    (x: Long, y: Long) => x*y
  )
   
  val prozessor = new Prozessor()
  var prozesse : Array[Prozess] = Array.ofDim(functions size)
  var i = 0;
  for (f <- functions) {
    prozesse(i) = new Prozess(i, f, prozessor);
    prozesse(i).start
    i += 1
  }
  Thread.sleep(1000)
  var out = ""
  for (p <- prozesse) { out += p.wertetabelle.mkString + "\n" }
  showMessageDialog(null, out, "Wertetabellen", -1)
  System.exit(0)  // der Prozessor wartet ja immer noch ...
}