return new CollapseBuilder(fessConfig.getIndexFieldContentMinhashBits())
                    .setMaxConcurrentGroupRequests(fessConfig.getQueryCollapseMaxConcurrentGroupResultsAsInteger())
                    .setInnerHits(innerHitBuilder);
        }
    }

    /**
     * Stores a document in the specified index.
     *
     * @param index the index name
     * @param obj   the document object to store