* @param target the target encoding name
     * @throws IllegalArgumentException if source or target is blank
     */
    public void addEncodingMapping(final String source, final String target) {
        if (StringUtil.isBlank(source) || StringUtil.isBlank(target)) {
            throw new IllegalArgumentException("Source and target encodings must not be blank.");
        }
        encodingMap.put(toLowerCase(source), target);
    }

    /**

     * @param maxLength The maximum content length in bytes
     * @throws CrawlerSystemException if the MIME type is blank or maxLength is negative
     */
    public void addMaxLength(final String mimeType, final long maxLength) {
        if (StringUtil.isBlank(mimeType)) {
            throw new CrawlerSystemException("MIME type is a blank.");
        }
        if (maxLength < 0) {

    }

    /**
     * Checks if the request header is valid.
     * A header is considered valid if its name is not blank and its value is not null.
     * @return true if the header is valid, false otherwise.
     */
    public boolean isValid() {
        if (StringUtil.isBlank(name) || value == null) {
            return false;
        }

        return true;
    }

        if (StringUtil.isBlank(endpoint)) {
            throw new CrawlingAccessException("endpoint is blank.");
        }
        builder.endpoint(endpoint);
        final String accessKey = getInitParameter("accessKey", null, String.class);
        if (StringUtil.isBlank(accessKey)) {
            throw new CrawlingAccessException("accessKey is blank.");
        }

     *
     * @param key       The key associated with the extractor. Must not be null or blank.
     * @param extractor The extractor to add. Must not be null.
     */
    public void addExtractor(final String key, final Extractor extractor) {
        if (StringUtil.isBlank(key)) {
            throw new CrawlerSystemException("The key is null.");
        }
        if (extractor == null) {

            final String region = System.getenv().get("STORAGE_SECRET_KEY");
            try {
                if (StringUtil.isBlank(endpoint)) {
                    throw new IOException("endpoint is blank.");
                }
                final Builder builder = MinioClient.builder().endpoint(endpoint);

        final String url = urlQueue.getUrl();
        if (StringUtil.isBlank(url)) {
            if (logger.isDebugEnabled()) {
                logger.debug("URL is a blank: {}", url);
            }
            return false;
        }

        // check it in queue
        for (final UrlQueue<Long> urlInQueue : urlQueueList) {

     *
     * @param key   the key of the feature
     * @param value the value of the feature
     */
    public void addFeature(final String key, final String value) {
        if (StringUtil.isBlank(key) || StringUtil.isBlank(value)) {
            throw new CrawlerSystemException("key or value is null.");
        }

        featureMap.put(key, value);
    }

    /**
     * Adds a property to the extractor.

                    } finally {
                        CloseableUtil.closeQuietly(in);
                    }
                }, contentEncoding, normalizeText);
                if (StringUtil.isBlank(content)) {
                    if (resourceName != null) {
                        if (logger.isDebugEnabled()) {
                            logger.debug("retry without a resource name: {}", resourceName);

     */
    @Override
    public boolean visited(final OpenSearchUrlQueue urlQueue) {
        final String url = urlQueue.getUrl();
        if (StringUtil.isBlank(url)) {
            if (logger.isDebugEnabled()) {
                logger.debug("URL is a blank: {}", url);
            }
            return false;
        }

        final String sessionId = urlQueue.getSessionId();