Singleton sample

package {

    import flash.errors.IllegalOperationError;

    /**
     * Singleton
     *
     * @author Francois
     * @date 6 juin 2011;
     */
    public class Poil{

        private static var _instance:Poil;



        /* *********** *
         * CONSTRUCTOR *
         * *********** */
        /**
         * Creates an instance of <code>Poil</code>.
         */
        public function Poil(enforcer:SingletonEnforcer) {
            if(enforcer == null) {
                throw new IllegalOperationError("A singleton can't be instanciated. Use static accessor 'getInstance()'!");
            }
            initialize();
        }



        /* ***************** *
         * GETTERS / SETTERS *
         * ***************** */
        /**
         * Singleton instance getter.
         */
        public static function getInstance():Poil{
            if(_instance == null)_instance = new  Poil(new SingletonEnforcer());
            return _instance;
        }



        /* ****** *
         * PUBLIC *
         * ****** */




        /* ******* *
         * PRIVATE *
         * ******* */
        /**
         * Initialize the class.
         */
        private function initialize():void {

        }

    }
}

internal class SingletonEnforcer{}