try {
Element udElem = updateInfo.getUpdateElement();
boolean removeExisting = DomUtil.hasChildElement(udElem, ItemResourceConstants.XML_REMOVEEXISTING, ItemResourceConstants.NAMESPACE);
// register eventListener in order to be able to report the modified resources.
EventListener el = new EListener(updateInfo.getPropertyNameSet(), ms);
registerEventListener(el, session.getRootNode().getPath());
String[] hrefs = updateInfo.getVersionHref();
if (hrefs == null || hrefs.length < 1) {
throw new DavException(DavServletResponse.SC_BAD_REQUEST, "Invalid update request body: at least a single version href must be specified.");