/** {@inheritDoc} */
 public boolean validate(HttpServletRequest request, HttpServletResponse response) {
   if (requestURIRequiresAuthentication(request)) {
     if (isAuthenticationRequired(request)) {
       invalidate(request, response);
       return false;
     }
     // If URL requires auth and we are authenticated refresh the session.
     // We don't refresh when the URL doesn't require auth because
     // that may invalidate our old session
     pxtDelegate.refreshPxtSession(request, response);
   }
   return true;
 }