*/
    public void addField(final String field) {
        fields.add(field);
    }

    /**
     * Adds a kind to filter by.
     * @param kind The kind.
     */
    public void addKind(final String kind) {
        kinds.add(kind);
    }

    /**
     * Sets whether to return detailed suggestion information.

    }

    @Test
    public void testConcatKinds() {
        // Test static concatKinds method
        SuggestItem.Kind[] kinds1 = { SuggestItem.Kind.QUERY };
        SuggestItem.Kind[] kinds2 = { SuggestItem.Kind.DOCUMENT, SuggestItem.Kind.QUERY };

        SuggestItem.Kind[] result = SuggestItem.concatKinds(kinds1, kinds2);

        assertNotNull(result);
        assertEquals(2, result.length); // Should not have duplicates

    }

    /**
     * Merges two Kind arrays, maintaining uniqueness.
     */
    private static SuggestItem.Kind[] mergeKinds(final SuggestItem.Kind[] kinds1, final SuggestItem.Kind[] kinds2) {
        final Set<SuggestItem.Kind> merged = new LinkedHashSet<>();

        if (kinds1 != null) {
            Collections.addAll(merged, kinds1);
        }

        if (kinds2 != null) {

        assertEquals(SuggestItem.Kind.QUERY, result[0]);
    }

    @Test
    public void test_concatKinds_secondEmpty() {
        SuggestItem.Kind[] kinds1 = { SuggestItem.Kind.DOCUMENT };

        SuggestItem.Kind[] result = SuggestItem.concatKinds(kinds1, new SuggestItem.Kind[0]);

        assertEquals(1, result.length);
        assertEquals(SuggestItem.Kind.DOCUMENT, result[0]);
    }

    @Test

            }
        }
    }

    /**
     * Concatenates kind arrays, avoiding duplicates.
     * @param kinds The initial kind array.
     * @param newKinds The new kind array to add.
     * @return The concatenated kind array.
     */
    protected static Kind[] concatKinds(final Kind[] kinds, final Kind... newKinds) {
        if (kinds == null) {
            return newKinds;
        }

-->

#### What type of PR is this?

<!--
Add one of the following kinds:
/kind bug
/kind dependency
/kind cleanup
/kind documentation
/kind feature

Optionally add one or more of the following kinds if applicable:
/kind api-change
/kind deprecation
/kind failing-test
/kind flake
/kind regression
-->

#### What this PR does / why we need it:

        final SuggestItem.Kind[] itemKinds = new SuggestItem.Kind[kinds.size()];
        for (int i = 0; i < kinds.size(); i++) {
            final String kind = kinds.get(i);
            if (kind.equals(SuggestItem.Kind.DOCUMENT.toString())) {
                itemKinds[i] = SuggestItem.Kind.DOCUMENT;
            } else if (kind.equals(SuggestItem.Kind.QUERY.toString())) {

        return deleteWordsByKind(index, FieldNames.QUERY_FREQ, SuggestItem.Kind.QUERY, item -> item.setQueryFreq(0),
                SuggestItem.Kind.DOCUMENT, SuggestItem.Kind.USER);
    }

    /**
     * Common method to delete words by kind.
     *
     * @param index The index name
     * @param freqField The frequency field name
     * @param kindToRemove The kind to remove
     * @param freqSetter The consumer to set frequency to 0

        boolQueryBuilder.must(QueryBuilders.termQuery(FieldNames.KINDS, SuggestItem.Kind.DOCUMENT.toString()));
        boolQueryBuilder.mustNot(QueryBuilders.termQuery(FieldNames.KINDS, SuggestItem.Kind.QUERY.toString()));
        boolQueryBuilder.mustNot(QueryBuilders.termQuery(FieldNames.KINDS, SuggestItem.Kind.USER.toString()));

        source.put(FieldNames.TAGS, Arrays.asList("tag1"));
        source.put(FieldNames.ROLES, Arrays.asList("role1"));
        source.put(FieldNames.LANGUAGES, Arrays.asList("en"));
        source.put(FieldNames.KINDS, Arrays.asList("document"));
        source.put(FieldNames.TIMESTAMP, System.currentTimeMillis());

        SuggestItem item = SuggestItemSerializer.fromSource(source);

        assertNotNull(item);