}
        }
    }

    /**
     * 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;
        }

    /** The document frequency field. */
    public static final String DOC_FREQ = "docFreq";
    /** The user boost field. */
    public static final String USER_BOOST = "userBoost";
    /** The kinds field. */
    public static final String KINDS = "kinds";
    /** The timestamp field. */
    public static final String TIMESTAMP = "@timestamp";
    /** The tags field. */
    public static final String TAGS = "tags";
    /** The roles field. */

    @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

        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

    }

    /**
     * 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) {

-->

#### What type of PR is this?

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Add one of the following kinds:
/kind bug
/kind dependency
/kind cleanup
/kind documentation
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Optionally add one or more of the following kinds if applicable:
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/kind deprecation
/kind failing-test
/kind flake
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-->

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

     */
    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.

### SuggestItem (Domain Entity)
Location: `src/main/java/org/codelibs/fess/suggest/entity/SuggestItem.java`

Core attributes: `text`, `timestamp`, `queryFreq`, `docFreq`, `userBoost`, `readings`, `tags`, `roles`, `languages`, `kinds`

Kind types: `DOCUMENT`, `QUERY`, `USER`

---

## Development Workflow

### Build Commands

```bash
mvn compile                              # Compile

        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())) {

    }

    public MaxCodePoint(String userFriendly) {
      value = decode(userFriendly);
    }
  }

  /**
   * The default values of maxCodePoint below provide pretty good performance models of different
   * kinds of common human text.
   *
   * @see MaxCodePoint#decode
   */
  @Param({"0x80", "0x90", "0x100", "0x800", "0x10000", "0x10ffff"})
  MaxCodePoint maxCodePoint;

  @Param({"16384"})
  int charCount;