code: protected FilterBuilder add(HttpSupportFilter... filters) {
          for (HttpSupportFilter filter : filters) {
              if(allFilters.contains(filter)){
                  throw new IllegalArgumentException("Cannot register the same filter instance more than once.");
              }
          }
          allFilters.addAll(Collections.list(filters));
          return new FilterBuilder(filters);
      }
docs: Adds a set of filters to a set of controllers.
  The filters are invoked in the order specified. Will reject adding the same instance of a filter more than once.
  
  @param filters filters to be added.
  @return object with <code>to()</code> method which accepts a controller class.