public function setDirectory($path) {
        if (substr($path, -1) !== '/') {
            $path .= '/';
        }

        if (!file_exists($path)) {
            mkdir($path, 0777, true);

        } else if (!is_writable($path)) {
            chmod($path, 0777);
        }

        $this->_directory = $path;

        return $this;
    }