public void doPreInvoke(SipServletRequest request) {
StandardContext context = (StandardContext) getContainer();
Object[] instances = context.getApplicationEventListeners();
ServletRequestEvent event = null;
if ((instances != null) && (instances.length > 0)) {
event = new ServletRequestEvent(((StandardContext) container).getServletContext(),
request);
// create pre-service event
for (int i = 0; i < instances.length; i++) {
if (instances[i] == null) {