Scalaのactorについて

import scala.actors.Actor._;

object Execution {
  val b = new Array[byte](0x2000);
  object end;
  def watch() {
    loop {
      react {
        case ins : java.io.InputStream =>
          if (ins.available()>0) {
            val n = ins.read(b);
            print(new String(b, 0, n));
          }
          self ! ins;

        case end =>
          println("end watch!");
          exit("watch");
      }
    }
  }
  def input() {
    loop {
      receive {
        case out:java.io.PrintWriter =>
//          if (Console.in.ready()) {
            out.println(Console.readLine);
            out.flush();
//          }
          self ! out;

        case end =>
          println("end input!");
          exit("input");
      }
    }
  }

  def main(args :Array[String]): Unit = {
    val startTime = System.currentTimeMillis();
    val parameters = new java.util.ArrayList[String]();
    parameters.add("cmd");
    parameters.add("/C");
    for (p<-args) parameters.add(p);

    val pb = new ProcessBuilder(parameters);
    pb.redirectErrorStream(true);
    val process = pb.start();

    val watcher = actor(watch());
    val inputter = actor(input());

    watcher ! process.getInputStream();
    inputter ! new java.io.PrintWriter(process.getOutputStream());

    process.waitFor();

    inputter ! end;
    watcher ! end;

    val endTime = System.currentTimeMillis();
    println("main end " + (endTime-startTime) + "(ms)");
  }
}