public function init()
    {
        parent::init();

        if (strtoupper(substr(PHP_OS, 0, 3)) === 'WIN') {
            $this->windows = true;
        }

        if ($this->resource_directory) {
            if (!file_exists($this->resource_directory)) {
                throw new Exception('Invalid resource directory', 1);
            }
        }
    }