private final Map<String, Node> items = new HashMap<>();

        public void setNamedItem(String name, Node node) {
            items.put(name, node);
        }

        @Override
        public Node getNamedItem(String name) {
            return items.get(name);
        }

        @Override
        public Node setNamedItem(Node arg) {
            return null;
        }

        @Override

     * @return the thumbnail source URL if found, null otherwise
     */
    protected String getThumbnailSrc(final String url, final NamedNodeMap attributes) {
        final Node srcNode = attributes.getNamedItem("src");
        if (srcNode != null) {
            try {
                final URL thumbnailUrl = getURL(url, srcNode.getTextContent());
                if (thumbnailUrl != null) {