}
        }
    }

    /**
     * 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;
        }

        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?

<!--
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:

     */
    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())) {

        SuggestItem.Kind[] kinds1 = { SuggestItem.Kind.QUERY };
        SuggestItem.Kind[] kinds2 = { SuggestItem.Kind.QUERY, SuggestItem.Kind.DOCUMENT };

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

        // Should have QUERY from first, and only DOCUMENT added from second (QUERY already exists)
        assertEquals(2, result.length);
    }

        secondLine.put("score", (item.getQueryFreq() + item.getDocFreq()) * item.getUserBoost());
        secondLine.put("tags", item.getTags());
        secondLine.put("roles", item.getRoles());
        secondLine.put("kinds", Arrays.toString(item.getKinds()));
        secondLine.put("@timestamp", item.getTimestamp());

        try (OutputStream out1 = getXContentOutputStream(firstLineMap); OutputStream out2 = getXContentOutputStream(secondLine)) {

      checkState(
          this.maximumSize == UNSET_INT,
          "weigher can not be combined with maximum size (%s provided)",
          this.maximumSize);
    }

    // safely limiting the kinds of caches this can produce
    @SuppressWarnings("unchecked")
    CacheBuilder<K1, V1> me = (CacheBuilder<K1, V1>) this;
    me.weigher = checkNotNull(weigher);
    return me;
  }

  long getMaximumWeight() {