* This method follows the builder pattern for method chaining.
     *
     * @param sortField the field name to sort by
     * @return this QueryStringBuilder instance for method chaining
     */
    public QueryStringBuilder sortField(final String sortField) {
        this.sortField = sortField;
        return this;
    }

    /**
     * Sets whether to escape special characters in queries.

            }
            final String sortField = values[0];
            if (!getQueryFieldConfig().isSortField(sortField)) {
                throw new InvalidQueryException(
                        messages -> messages.addErrorsInvalidQueryUnsupportedSortField(UserMessages.GLOBAL_PROPERTY_KEY, sortField),
                        "Unsupported sort field: " + termQuery);
            }

    }

    @Test
    public void test_sortField() {
        final String query = new QueryStringBuilder().params(createSimpleParams("test")).sortField("score").build();
        assertEquals("test sort:score", query);

        final String queryWithoutSort = new QueryStringBuilder().params(createSimpleParams("test")).build();
        assertEquals("test", queryWithoutSort);

            request.setAttribute(Constants.REQUEST_QUERIES, params.getQuery());
        });

        String query = ComponentUtil.getQueryStringBuilder().params(params).sortField(params.getSort()).build();
        List<Map<String, Object>> documentItems;
        try {
            documentItems = searchInternal(query, params, userBean);
        } catch (final InvalidQueryException e) {

        return sortFields;
    }

    /**
     * Sets the fields that can be used for sorting search results.
     * Also updates the sortFieldSet for O(1) lookup performance.
     *
     * @param sortFields array of field names that can be used for sorting
     */
    public void setSortFields(final String[] sortFields) {
        this.sortFields = sortFields;
        sortFieldSet = new HashSet<>();

        queryFieldConfig.setSortFields(fields);

        // Verify array is set
        assertNotNull(queryFieldConfig.sortFields);
        assertSame(fields, queryFieldConfig.sortFields);
        assertEquals(3, queryFieldConfig.sortFields.length);

        // Verify Set is created and populated
        assertNotNull(queryFieldConfig.sortFieldSet);

        assertEquals(0, queryFieldConfig.notAnalyzedFieldSet.size());
    }

    @Test
    public void test_isSortField() {
        String[] sortFields = { "score", "created", "modified", "title" };
        queryFieldConfig.setSortFields(sortFields);

        // Test valid sort fields
        assertTrue(queryFieldConfig.isSortField("score"));
        assertTrue(queryFieldConfig.isSortField("created"));