childUrlSet.add(url);
    }

    /**
     * Add child URLs.
     * @param c the collection of request data to add to the child URL set
     */
    public void addAllUrl(final Collection<RequestData> c) {
        if (c != null) {
            childUrlSet.addAll(c);
        }
    }

    /**
     * Remove a child URL.

                }
                requestDataList = convertChildUrlList(requestDataList);
                resultData.addAllUrl(requestDataList);
            });

            resultData.addAllUrl(responseData.getChildUrlSet());

            final RequestData requestData = responseData.getRequestData();
            resultData.removeUrl(requestData);