protected function normalizeDirArray()
    {
        if (!isset($this->dir['iterate'])) {
            $this->dir['iterate'] = self::DEFAULT_ITERATE;
        }
        if (!isset($this->dir['path'])) {
            $this->dir['path'] = self::DEFAULT_PATH;
        }
        if (!isset($this->dir['recursive'])) {
            $this->dir['recursive'] = self::DEFAULT_RECURSIVE;
        }
    }