protected static function storeId($id)
    {
        $tokens    =  explode('-', $id);
        $container =& self::$ids;

        do {
            $token = array_shift($tokens);
            if (!isset($container[$token])) {
                $container[$token] = array();
            }
            $container =& $container[$token];
        } while (!empty($tokens));
    }