* @param docMap the document metadata map containing field values
     * @return a tuple containing the generator name, thumbnail ID, and path
     */
    @Override
    public Tuple3<String, String, String> createTask(final String path, final Map<String, Object> docMap) {
        final FessConfig fessConfig = ComponentUtil.getFessConfig();
        final String thumbnailId = DocumentUtil.getValue(docMap, fessConfig.getIndexFieldId(), String.class);

        }

        @Override
        public boolean isTarget(Map<String, Object> docMap) {
            return target;
        }

        @Override
        public Tuple3<String, String, String> createTask(String path, Map<String, Object> docMap) {
            return task;
        }

        @Override
        public void destroy() {
            // Do nothing
        }
    }

            if (generator.isTarget(docMap)) {
                final String path = getImageFilename(docMap);
                final Tuple3<String, String, String> task = generator.createTask(path, docMap);
                if (task != null) {
                    if (logger.isDebugEnabled()) {
                        logger.debug("Add thumbnail task: {}", task);
                    }