public function getRootPageId()
    {
        $rootPageId = 0;

        if (empty($this->rootLineArray)) {
            return $rootPageId;
        }

        foreach ($this->rootLineArray as $page) {
            if (Site::isRootPage($page)) {
                $rootPageId = $page['uid'];
            }
        }

        return $rootPageId;
    }