public function parseXml($xmlString)
    {
        Validate::notNull($xmlString, 'xmlString');
        Validate::isString($xmlString, 'xmlString');
        $atomLinkXml = simplexml_load_string($xmlString);
        $attributes = $atomLinkXml->attributes();

        if (!empty($attributes['href'])) {
            $this->href = (string) $attributes['href'];
        }

        if (!empty($attributes['rel'])) {
            $this->rel = (string) $attributes['rel'];
        }

        if (!empty($attributes['type'])) {
            $this->type = (string) $attributes['type'];
        }

        if (!empty($attributes['hreflang'])) {
            $this->hreflang = (string) $attributes['hreflang'];
        }

        if (!empty($attributes['title'])) {
            $this->title = (string) $attributes['title'];
        }

        if (!empty($attributes['length'])) {
            $this->length = (int) $attributes['length'];
        }

        $undefinedContent = (string) $atomLinkXml;
        if (empty($undefinedContent)) {
            $this->undefinedContent = null;
        } else {
            $this->undefinedContent = (string) $atomLinkXml;
        }
    }