AbstractFactory pattern with Scala

AbstractFactory.scala

/**
 * Example of AbstractFactory pattern
 *
 * create OS Specific GUIWidget with same operation.
 *
 */

trait Button {
  def paint: String
}

class WinButton extends Button {
  def paint: String = "I'm a WinButton"
}

class OSXButton extends Button {
  def paint: String = "I'm a OSXButton"
}

trait GUIFactory {
  def createButton: Button
}

class WinFactory extends GUIFactory {
  def createButton: Button = new WinButton
}

class OSXFactory extends GUIFactory {
  def createButton: Button = new OSXButton
}

class Application(factory: GUIFactory) {
  val button = factory.createButton
  println(button.paint)
}

object ApplicationRunner {
  def main(argv: Array[String]) {
    new Application(createOsSpecificFactory(argv(0)))
  }

  def createOsSpecificFactory(os_type: String): GUIFactory = {
    os_type match {
      case "Win" => new WinFactory
      case "OSX" => new OSXFactory
    }
  }
}

ApplicationRunner.main(Array("Win"))
ApplicationRunner.main(Array("OSX"))