nonvirtualswitch.scala

abstract class Foo(val tag : Int){
}
class Bar() extends Foo(0){
}

class Baz() extends Foo(1){
}

class Bif() extends Foo(2){
}

class Blort() extends Foo(3){
}

object Main{
  def size = 100000000;

  val items = new Array[Foo](size);

  println("Items allocated")

  val Bar = new Bar();
  val Baz = new Baz();
  val Bif = new Bif();
  val Blort = new Blort();

  var i = 0;
  while(i < items.length){
    items(i) = (i % 4) match {
      case 0 => Bar;
      case 1 => Baz;  
      case 2 => Bif;
      case 3 => Blort;
    }
    i += 1;
  }

  println("Items filled");

  var bar = 0;
  var baz = 0;
  var bif = 0;
  var blort = 0;

  def switchAt(i : Int) = items(i).tag match {
    case 0 => bar += 1;
    case 1 => baz += 1;
    case 2 => bif += 1;
    case 3 => blort += 1;
  }

  def instanceAt(i : Int) = {
    if (items(i).isInstanceOf[Bar]) bar += 1;
    else if (items(i).isInstanceOf[Baz]) baz += 1;
    else if (items(i).isInstanceOf[Bif]) bif += 1;
    else blort += 1;
  }

  def doSwitch = {
    val start = System.currentTimeMillis;
    var i = 0;
    while (i < items.length){
      switchAt(i);
      i += 1;
    }
    System.currentTimeMillis - start;
  }

  def doInstance = {
    val start = System.currentTimeMillis;
    var i = 0;
    while (i < items.length){
      instanceAt(i);
      i += 1;
    }
    System.currentTimeMillis - start;
  }

  def main(args : Array[String]){
    println("Starting tests...") 
 
    for(_ <- 0 until 10){
      println("Switch: " + doSwitch);
      println("Instance: " + doInstance);
    }
  }

}