if (StringUtil.isNotBlank(fessConfig.getQueryFacetFieldsSort())) {
            sort = fessConfig.getQueryFacetFieldsSort();
        }
        if (StringUtil.isNotBlank(fessConfig.getQueryFacetFieldsMissing())) {
            missing = fessConfig.getQueryFacetFieldsMissing();
        }
    }

    /**
     * Converts the sort string into a BucketOrder object for OpenSearch aggregations.

     * The value is, e.g.  <br>
     * comment: Value for missing facet fields.
     * @return The value of found property. (NotNull: if not found, exception but basically no way)
     */
    String getQueryFacetFieldsMissing();

    /**
     * Get the value for the key 'query.facet.fields.missing' as {@link Integer}. <br>
     * The value is, e.g.  <br>
     * comment: Value for missing facet fields.