code: public AbstractHandlerMapping getHandlerMapping() {
  		Map<String, Object> urlMap = new LinkedHashMap<>();
  		for (WebMvcWampWebSocketEndpointRegistration registration : this.registrations) {
  			MultiValueMap<HttpRequestHandler, String> mappings = registration
  					.getMappings();
  			for (HttpRequestHandler httpHandler : mappings.keySet()) {
  				for (String pattern : mappings.get(httpHandler)) {
  					urlMap.put(pattern, httpHandler);
  				}
  			}
  		}
  		SimpleUrlHandlerMapping hm = new SimpleUrlHandlerMapping();
  		hm.setUrlMap(urlMap);
  		hm.setOrder(this.order);
  		if (this.urlPathHelper != null) {
  			hm.setUrlPathHelper(this.urlPathHelper);
  		}
  		return hm;
  	}
docs: Return a handler mapping with the mapped ViewControllers; or {@code null} in case
  of no registrations.