* encoding for URL decoding.</p>
 *
 * <p>Example usage:</p>
 * <pre>
 * {@code
 * IdnDnsResolver resolver = new IdnDnsResolver();
 * resolver.setFlag(IDN.ALLOW_UNASSIGNED);
 * resolver.setEncoding("UTF-8");
 * InetAddress[] addresses = resolver.resolve("example.com");
 * }
 * </pre>
 *
 */
public class IdnDnsResolver implements DnsResolver {

    /** Flag for IDN conversion. */

     * Constructs a new request.
     */
    public Request() {
        // nothing
    }

    /**
     * Executes the request.
     * @param client The OpenSearch client.
     * @return A Promise that will be resolved with the response or rejected with an error.
     */
    public Deferred<T>.Promise execute(final Client client) {
        final String error = getValidationError();
        if (!Strings.isNullOrEmpty(error)) {

    private final CountDownLatch latch = new CountDownLatch(1);

    /**
     * Resolves the deferred computation with the given response.
     * @param r The response.
     */
    public void resolve(final RESPONSE r) {
        final ArrayList<Consumer<RESPONSE>> executeCallbacks;
        synchronized (Deferred.this) {

    public void test_toAscii() {
        IdnDnsResolver resolver = new IdnDnsResolver();

        String host = "www.codelibs.org";
        String expected = "www.codelibs.org";
        assertEquals(expected, resolver.toAscii(host));

        host = "テスト.org";
        expected = "xn--zckzah.org";
        assertEquals(expected, resolver.toAscii(host));

        host = "xn--zckzah.org";

        Thread th = new Thread(() -> {
            try {
                Thread.sleep(1000);
            } catch (InterruptedException ignore) {}
            deferred.resolve(new SuggestResponse("", 0, Collections.emptyList(), 0, null));
        });
        th.start();

        final CountDownLatch latch = new CountDownLatch(1);
        deferred.promise().then(response -> latch.countDown());

            throw new CrawlerSystemException("Failed to create XPath instance.", e);
        }
    }

    /**
     *  Use an XPath string to select a nodelist.
     *  XPath namespace prefixes are resolved from the contextNode.
     *
     *  @param contextNode The node to start searching from.
     *  @param expression A valid XPath string.
     *  @return A XPathNodes, should never be null.
     *

    public RequestBuilder(final Client client, final Req request) {
        this.client = client;
        this.request = request;
    }

    /**
     * Executes the request.
     * @return A Promise that will be resolved with the response or rejected with an error.
     */
    public Deferred<Res>.Promise execute() {
        return request.execute(client);
    }

        super(indexSettings, name, settings);

        final String suffixWordsPath = settings.get("suffix_words_path");

        if (suffixWordsPath != null) {
            final File suffixWordsFile = environment.configDir().resolve(suffixWordsPath).toFile();
            try (Reader reader = IOUtils.getDecodingReader(new FileInputStream(suffixWordsFile), StandardCharsets.UTF_8)) {
                suffixWords = WordlistLoader.getWordSet(reader);

                if (filePath == null) {
                    throw new IllegalArgumentException("synonyms_path is not found.");
                }

                final Path path = env.configDir().resolve(filePath);

                try {
                    final File file = path.toFile();
                    if (file.exists()) {
                        reloadableFile = file;
                    }

            final Settings settings) {
        super(indexSettings, name, settings);

        final String path = settings.get("keywords_path");
        if (path != null) {
            keywordPath = environment.configDir().resolve(path);
        } else {
            keywordPath = null;
        }

        reloadInterval = settings.getAsTime("reload_interval", TimeValue.timeValueMinutes(1)).getMillis();
    }

    @Override