return SuggestItemSerializer.toSource(this);
    }

    /**
     * Parses a source map and returns a SuggestItem instance.
     * @param source The source map.
     * @return A SuggestItem instance.
     */
    public static SuggestItem parseSource(final Map<String, Object> source) {
        return SuggestItemSerializer.fromSource(source);
    }

    /**

        String[] languages = { "en" };
        long docFreq = 10L;
        long queryFreq = 5L;
        float userBoost = 1.5f;

        SuggestItem item =
                new SuggestItem(text, readings, fields, docFreq, queryFreq, userBoost, tags, roles, languages, SuggestItem.Kind.DOCUMENT);

        Map<String, Object> source = SuggestItemSerializer.toSource(item);

        assertNotNull(source);

        List<SuggestItem> items =
                parser.parseQueryLog(queryLog, supportedFields, tagFieldNames, roleFieldName, defaultReadingConverter, defaultNormalizer);

        assertTrue(items.size() > 0);
        SuggestItem item = items.get(0);
        assertTrue("Should have multiple tags", item.getTags().length >= 2);
    }

     * @return The SuggestIndexResponse
     */
    public SuggestIndexResponse index(final String index, final SuggestItem[] items, final String[] badWords) {
        final SuggestItem[] filteredItems = Stream.of(items).filter(item -> !item.isBadWord(badWords)).toArray(SuggestItem[]::new);

        if (logger.isDebugEnabled()) {

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

        assertEquals(0, result.length);
    }

    @Test
    public void test_concatKinds_firstEmpty() {
        SuggestItem.Kind[] kinds2 = { SuggestItem.Kind.QUERY };

        SuggestItem.Kind[] result = SuggestItem.concatKinds(new SuggestItem.Kind[0], kinds2);

        SuggestItem item3 = new SuggestItem(new String[] { "テスト" }, readings, new String[] { "content" }, 3, 0, -1, new String[] { "tag1" },
                new String[] { SuggestConstants.DEFAULT_ROLE }, null, SuggestItem.Kind.DOCUMENT);
        SuggestItem item4 = new SuggestItem(new String[] { "テスト" }, readings, new String[] { "content" }, 4, 0, -1, new String[] { "tag1" },

    }

    private SuggestItem createItemWithRoles(String text, String... roles) {
        String[] texts = { text };
        String[][] readings = { { "reading" } };
        String[] fields = { "field" };

        return new SuggestItem(texts, readings, fields, 1L, 1L, 1.0f, new String[0], roles, new String[0], SuggestItem.Kind.DOCUMENT);

        readings3[0] = new String[] { "both" };
        items[2] = new SuggestItem(new String[] { "両方" }, readings3, new String[] { "content" }, 1L, 1L, -1.0f, new String[] { "tag1" },
                new String[] { SuggestConstants.DEFAULT_ROLE }, null, SuggestItem.Kind.DOCUMENT);
        items[2].setKinds(new SuggestItem.Kind[] { SuggestItem.Kind.DOCUMENT, SuggestItem.Kind.QUERY });

        suggester.indexer().index(items);

     * </ul>
     *
     * @param item1 The first SuggestItem (base item)
     * @param item2 The second SuggestItem (item to merge in)
     * @return A new merged SuggestItem
     * @throws IllegalArgumentException if item IDs don't match
     */
    public static SuggestItem merge(final SuggestItem item1, final SuggestItem item2) {
        if (!item1.getId().equals(item2.getId())) {

        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())) {