code: public static void bind(Source source, RouteParameterHandler handler) {
          if (BINDINGS.containsKey(source)) {
              LoggerFactory.getLogger(Bindings.class).warn("Replacing a route parameter binding for {} by {}",
                      source.name(), handler);
          }
          BINDINGS.put(source, handler);
      }
docs: Associates the given source to the given handler.
  
  @param source  the source, must not be {@code null}
  @param handler the handler, must not be {@code null}