// host
        // site
        // url
        // anchor
        // content_length
        // last_modified
        // id
        // virtual_host
        defaultDataMap.put(fessConfig.getIndexFieldVirtualHost(),
                stream(config.getVirtualHosts()).get(stream -> stream.filter(StringUtil::isNotBlank).collect(Collectors.toList())));

        final FessConfig fessConfig = ComponentUtil.getFessConfig();
        final QueryBuilder queryBuilder = QueryBuilders.termQuery(fessConfig.getIndexFieldVirtualHost(), virtualHost);
        return deleteByQueryBuilder(searchEngineClient, index, queryBuilder);
    }

    /**
     * Deletes documents using the specified query builder and refreshes the index.

        putResultDataBody(dataMap, fessConfig.getIndexFieldRole(), roleTypeList);
        // virtualHosts
        putResultDataBody(dataMap, fessConfig.getIndexFieldVirtualHost(),
                stream(crawlingConfig.getVirtualHosts()).get(stream -> stream.filter(StringUtil::isNotBlank).collect(Collectors.toList())));
        // TODO date
        // lang

        putResultDataBody(dataMap, fessConfig.getIndexFieldRole(), roleTypeList);
        // virtualHosts
        putResultDataBody(dataMap, fessConfig.getIndexFieldVirtualHost(),
                stream(crawlingConfig.getVirtualHosts()).get(stream -> stream.filter(StringUtil::isNotBlank).collect(Collectors.toList())));
        // id

     * comment: Field name for virtual host in the index.
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getIndexFieldVirtualHost();

    /**
     * Get the value for the key 'response.field.content_title'. <br>
     * The value is, e.g. content_title <br>
     * comment: Field name for content title in the response.