this.queryBuilder = queryBuilder;
    }

    /**
     * Adds a sort builder.
     * @param sortBuilder The sort builder.
     */
    public void addSort(final SortBuilder<?> sortBuilder) {
        sortList.add(sortBuilder);
    }

    /**
     * Sets the limit document number percentage.
     * @param limitPercentage The limit percentage as a string (e.g., "50%").

        int num = 10000;

        addDocument(indexName, client, num);

        ESSourceReader reader = new ESSourceReader(client, settings, indexName);
        reader.setScrollSize(1000);
        reader.addSort(SortBuilders.fieldSort("field2"));
        int count = 0;
        int prev = -1;
        Map<String, Object> source;
        while ((source = reader.read()) != null) {

        // set query.
        final QueryBuilder q = buildQuery(query, fields);

        // set function score
        final QueryBuilder queryBuilder = buildFunctionScoreQuery(query, q);
        builder.addSort("_score", SortOrder.DESC);

        // set filter query.
        final List<QueryBuilder> filterList = new ArrayList<>(10);
        if (!tags.isEmpty()) {

                builder.setQuery(QueryBuilders.matchAllQuery());
            }
            if (sortBuilders != null) {
                for (SortBuilder<?> sortBuilder : sortBuilders) {
                    builder.addSort(sortBuilder);
                }
            }
            if (from != null) {
                builder.setFrom(from);
            }
            if (size != null) {
                builder.setSize(size);