/*******************************************************************************/


abstract class Scene {
  abstract void draw();
  abstract void update();
}

Hashtable scenes = new Hashtable();

Scene getScene(String s) {
  try {
    return getScene(Class.forName(getClass().getName()+'$'+s+"Scene"));
  } catch (ClassNotFoundException ex) {
    ex.printStackTrace();
    return null;
  }
}
Scene getScene(Class clazz) {
  Object o = scenes.get(clazz);
  if (o!=null) return (Scene)o;
  try {
    // instantiate the inner class
    o = clazz.getConstructor(new Class[]{getClass()}).newInstance(new Object[]{this});
  } catch (Exception ex) {
    ex.printStackTrace();
  }
  scenes.put(clazz,o);
  return (Scene)o;
}