public function autoload($className)
    {
        if ($this->namespace == null || $this->namespace.'\\' === substr($className, 0, strlen($this->namespace.'\\'))) {
            $fileName = dirname(__FILE__).DIRECTORY_SEPARATOR.'..'.DIRECTORY_SEPARATOR;
            $namespace = '';
            if (false !== ($lastNsPos = strripos($className, '\\'))) {
                $namespace = substr($className, 0, $lastNsPos);
                $className = substr($className, $lastNsPos + 1);
                $fileName .= str_replace('\\', DIRECTORY_SEPARATOR, $namespace) . DIRECTORY_SEPARATOR;
            }
            $fileName .= str_replace('_', DIRECTORY_SEPARATOR, $className) . '.php';
            require $fileName;
        }
    }