this.data = data;
    }

    /**
     * Add a child URL.
     * @param url the request data to add to the child URL set
     */
    public void addUrl(final RequestData url) {
        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) {

/**
 * {@link ChildUrlsException} is thrown when child URLs are found during crawling.
 * It extends {@link CrawlerSystemException} and holds a set of {@link RequestData}
 * representing the child URLs that caused the exception.
 *
 */
public class ChildUrlsException extends CrawlerSystemException {

    private static final long serialVersionUID = 1L;

    /**
     * The list of child URLs.
     */

    /** Indicates processing a response. */
    PROCESS_RESPONSE,
    /** Indicates the crawling process has finished. */
    FINISHED_CRAWLING,
    /** Indicates processing child URLs due to an exception. */
    PROCESS_CHILD_URLS_BY_EXCEPTION,
    /** Indicates processing a child URL due to an exception. */
    PROCESS_CHILD_URL_BY_EXCEPTION,
    /** Indicates an access exception during crawling. */
    CRAWLING_ACCESS_EXCEPTION,

<!DOCTYPE components PUBLIC "-//DBFLUTE//DTD LastaDi 1.0//EN"
	"http://dbflute.org/meta/lastadi10.dtd">
<components namespace="fessCrawler">
	<include path="crawler/container.xml" />

	<!-- Converts child links to normalize it. -->
	<component name="urlConvertHelper" class="org.codelibs.fess.crawler.helper.UrlConvertHelper">
	</component>

 * and adds them as child URLs to be crawled.
 *
 * <p>
 * This class uses a {@link SitemapsHelper} to parse the sitemap XML or text.
 * It then iterates through the sitemaps in the SitemapSet, extracts the URL
 * from each sitemap, and creates a new {@link RequestData} object for each URL.
 * These RequestData objects are added to a set of child URLs, which are then