code: public boolean validate (boolean asError) {
          for (WidgetValidator<?,?> validator : _validators) {
              if (!validator.validate(asError)) return false;
          }
          return true;
      }
docs: Executes all registered validators (in registration order). If any validator fires a rule
  that fails, its feedback will be displayed, the validation process will be stopped, and
  false will be returned. If all validators succeed, true will be returned.