return null; } protected function set($key, $value) { $this->values[$key] = $value; } static function getRequest() { return self::instance()->get('request'); } static function setRequest(Request_2 $request) { return self::instance()->set('request', $request); } } RequestRegistry::setRequest(new Request_2()); print_r(RequestRegistry::getRequest()); class SessionRegistry extends Registry { private static $instance; private function __construct() { //session_start(); } static function instance() { if (!isset(self::$instance)) { self::$instance = new self(); } return self::$instance; }