public String getAnnouncementHtml(HttpSession session, ServletConfig config) {
String notificationHtml = (String)session.getAttribute(NOTIFIER_HTML_KEY);
if (notificationHtml == null || isSessionChanged(session)) {
try {
AnnouncementServiceClient client = new AnnouncementServiceClient(config, session);
String regId = client.retrieveRegId();
String notificationUrl = Util.generateAnnouncementURL(regId, session);
notificationHtml = Util.getAnnouncementHtml(notificationUrl);
session.setAttribute(NOTIFIER_HTML_KEY, notificationHtml);
} catch (Exception e) {