/**
     * Registers a callback to be executed when the computation is complete.
     * @param consumer The callback.
     * @return The promise.
     */
    public Promise then(final Consumer<RESPONSE> consumer) {
        return promise.then(consumer);
    }

    /**
     * Registers a callback to be executed when the computation fails.
     * @param consumer The callback.
     * @return The promise.
     */

 *
 * <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
 * passed to a {@link ChildUrlsException} to be processed by the crawler.
 * </p>
 *
 * <p>

 *
 * <p>
 * The transform method takes a ResponseData object, checks if it has a response body,
 * and then reads the body into a byte array. This byte array is then set as the data
 * in the ResultData object.
 * </p>
 *
 * <p>
 * The getData method takes an AccessResultData object, checks if the transformer name matches,
 * and then returns the data as a ByteArrayInputStream.
 * </p>
 */

 *   <li>Dynamic passwords provided through extraction parameters</li>
 * </ul>
 *
 * <p>Passwords are matched against URLs or resource names using regular expression patterns.
 * The extractor first tries to match against the URL, then falls back to the resource name if available.
 *
 * @author shinsuke
 */
public abstract class PasswordBasedExtractor extends AbstractExtractor {

    /** Logger instance for this class. */

        return inputStream.read();
    }

    /**
     * Reads up to len bytes of data from the input stream into an array of bytes.
     *
     * @param b the buffer into which the data is read
     * @param off the start offset in array b at which the data is written
     * @param len the maximum number of bytes to read

     *
     * <p>This method iterates through the provided array of SuggestItem objects and merges
     * items that have the same ID. The merged items are added to a new list, which is then
     * converted back to an array and returned.</p>
     *
     * @param items an array of SuggestItem objects to be merged
     * @return an array of merged SuggestItem objects
     */

 * It uses an Extractor to extract the text from the response body based on the MIME type.
 * The extracted text is then converted into a byte array using the specified charset encoding.
 * It also provides a method to retrieve the extracted data as a String from an AccessResultData object.
 *
 * <p>

 * represents a valid sitemap. It uses a SitemapsHelper to validate the response body as an InputStream.
 * The rule checks if the URL matches the defined regex pattern and then validates the content as a sitemap.
 * If any exception occurs during the sitemap validation, it logs the error and returns false.
 *
 */
public class SitemapsRule extends RegexRule {
    /**

     *  The implementation of this is a little slow, since it creates
     *  a number of objects each time it is called.  This could be optimized
     *  to keep the same objects around, but then thread-safety issues would arise.
     *
     *  @param contextNode The node to start searching from.
     *  @param expression A valid XPath string.

 * {@link XpathTransformer} is a class that transforms HTML content into XML format based on XPath expressions.
 * It extracts data from an HTML document by applying XPath rules defined in {@link #fieldRuleMap}.
 * The extracted data is then formatted into an XML structure and stored in the {@link ResultData}.
 * <p>
 * This class extends {@link HtmlTransformer} and overrides the {@link #storeData(ResponseData, ResultData)} method