try {
            if (fessConfig.isThumbnailCrawlerEnabled()) {
                final ThumbnailManager thumbnailManager = ComponentUtil.getThumbnailManager();
                final String thumbnailField = fessConfig.getIndexFieldThumbnail();
                docList.stream().forEach(doc -> {
                    if (!thumbnailManager.offer(doc)) {
                        if (logger.isDebugEnabled()) {

            putResultDataBody(dataMap, fessConfig.getIndexFieldUrl(), url); // set again
        }
        // thumbnail
        putResultDataBody(dataMap, fessConfig.getIndexFieldThumbnail(), responseData.getUrl());

        // from config
        final String scriptType = crawlingConfig.getScriptType();

        }
        // thumbnail
        final String thumbnailUrl = getThumbnailUrl(responseData, document);
        if (StringUtil.isNotBlank(thumbnailUrl)) {
            putResultDataBody(dataMap, fessConfig.getIndexFieldThumbnail(), thumbnailUrl);
        }

        // from config
        final String scriptType = crawlingConfig.getScriptType();

     * The value is, e.g. thumbnail <br>
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getIndexFieldThumbnail();

    /**
     * Get the value for the key 'index.field.virtual_host'. <br>
     * The value is, e.g. virtual_host <br>