code: static void checkOnlyPostParameters(final String method, final Map parameterMap, final Set<String> onlyPostParameters) {
          if (!"POST".equals(method)) {
              Set<String> names = parameterMap.keySet();
              for (String onlyPostParameter : onlyPostParameters) {
                  if (names.contains(onlyPostParameter)) {
                      FilterUtils.logException(LOGGER, new IllegalArgumentException(onlyPostParameter + " parameter should only be used in POST requests"));
                  }
              }
          }
      }
docs: Check that some parameters should only be in POST requests (according to the configuration).
  
  @param method             the method of the request
  @param parameterMap       all the request parameters
  @param onlyPostParameters parameters that should only be in POST requests