private function serializeElem(DOMDocument $doc_xml, DOMElement $parent_xml, $id, MenuElem $menu_elem)
{
$menu_elem_xml = $doc_xml->createElement('menu-elem');
$menu_elem_xml->setAttribute('id', $id);
$label_xml = $doc_xml->createElement('label', $menu_elem->getLabel());
$url_xml = $doc_xml->createElement('url', $menu_elem->getUrl());
$menu_elem_xml->appendChild($label_xml);
$menu_elem_xml->appendChild($url_xml);
$menu_children = $menu_elem->getChildren();
if ($menu_children) {
$submenu_xml = $doc_xml->createElement('submenu');
$menu_elem_xml->appendChild($submenu_xml);
foreach ($menu_children as $child_id => $child_elem) {
$this->serializeElem($doc_xml, $submenu_xml, $child_id, $child_elem);
}
}
$parent_xml->appendChild($menu_elem_xml);
}
