code: @Override
      protected ModelAndView handleRequestInternal(final HttpServletRequest request, final HttpServletResponse response) throws Exception {
          for (val delegate : this.delegates) {
              if (delegate.canHandle(request, response)) {
                  return delegate.handleRequestInternal(request, response);
              }
          }
          return generateErrorView(CasProtocolConstants.ERROR_CODE_INVALID_REQUEST, null);
      }
docs: Handles the request.
  Ask all delegates if they can handle the current request.
  The first to answer true is elected as the delegate that will process the request.
  If no controller answers true, we redirect to the error page.
  
  @param request  the request to handle
  @param response the response to write to
  @return the model and view object
  @throws Exception if an error occurs during request handling