protected function _configRead($key)
    {
        if ($key === null) {
            return $this->_config;
        }

        if (strpos($key, '.') === false) {
            return isset($this->_config[$key]) ? $this->_config[$key] : null;
        }

        $return = $this->_config;

        foreach (explode('.', $key) as $k) {
            if (!is_array($return) || !isset($return[$k])) {
                $return = null;
                break;
            }

            $return = $return[$k];
        }

        return $return;
    }