package
{
	public class WaterproofSingleton {
		static private var _instance:Singleton;
 
		public function Singleton(singletonEnforcer:SingletonEnforcer) {
			if ((singletonEnforcer as SingletonEnforcer) == null) {
				throw (new Error("Direct instantiation of a Singleton is not allowed!"));
			}
		}
 
		public static function getInstance():Singleton {
			if (Singleton._instance == null) {
				Singleton._instance = new Singleton(new SingletonEnforcer());
			}
			return Singleton._instance;
		}
	}
}
 
class SingletonEnforcer {}