NormalizerChain chain = new NormalizerChain();
        Normalizer normalizer1 = (text, field, langs) -> text + "-1";
        Normalizer normalizer2 = (text, field, langs) -> text + "-2";
        Normalizer normalizer3 = (text, field, langs) -> text + "-3";

        chain.add(normalizer1);
        chain.add(normalizer2);
        chain.add(normalizer3);

        @Override
        public List<String> convert(String text, String field, String... langs) throws IOException {
            if (text == null || text.isEmpty()) {
                return Collections.emptyList();
            }

            List<String> readings = new ArrayList<>();

            if (langs == null || langs.length == 0) {
                readings.add(text.toUpperCase());
            } else {

public interface Normalizer {
    /**
     * Normalizes the given text.
     * @param text The text to normalize
     * @param field The field name
     * @param langs The language
     * @return The normalized text
     */
    String normalize(String text, String field, String... langs);

     * @param searchWord Search word
     * @param field Field
     * @param langs Languages
     * @param analyzer Analyzer
     * @return True if the search word is excluded
     */
    protected boolean isExcludeSearchword(final String searchWord, final String field, final String[] langs,
            final SuggestAnalyzer analyzer) {
        if (langs == null || langs.length == 0) {

    public String normalize(final String text, final String field, final String... langs) {
        final Normalizer normalizer;
        if (langs == null || langs.length == 0) {
            normalizer = new LangAnalyzerNormalizer(null);
        } else {
            final NormalizerChain chain = new NormalizerChain();
            for (final String lang : langs) {
                chain.add(new LangAnalyzerNormalizer(lang));
            }

        final ReadingConverter converter;
        if (langs == null || langs.length == 0) {
            converter = new LangAnalyzerConverter(null);
        } else {
            final ReadingConverterChain chain = new ReadingConverterChain();
            for (final String lang : langs) {
                chain.addConverter(new LangAnalyzerConverter(lang));

    @Override
    public String normalize(final String text, final String field, final String... langs) {
        if (text == null) {
            return null;
        }
        String tmp = text;
        for (final Normalizer normalizer : normalizers) {
            tmp = normalizer.normalize(tmp, field, langs);
            if (tmp == null) {
                return null;
            }
        }
        return tmp;

        // Test convert with null languages
        String text = "test text";
        String field = "content";
        String[] langs = null;

        List<String> results = converter.convert(text, field, langs);

        assertNotNull(results);
        // Results may vary based on analyzer configuration
    }

    @Test

     * @param field the field to be used for conversion.
     * @param langs the languages to be used for conversion.
     * @return a list of readings for the given text.
     * @throws IOException if an I/O error occurs during conversion.
     */
    List<String> convert(String text, String field, String... langs) throws IOException;

          TimeoutsToUse.FINITE,
          isBoolean(method) ? Outcome.FAILURE : Outcome.HANG);
      addTests(
          suite,
          method,
          Scenario.SATISFIED_AND_OCCUPIED_BEFORE_ENTERING,
          TimeoutsToUse.INFINITE,
          isGuarded(method) ? Outcome.HANG : (isTryEnter(method) ? Outcome.FAILURE : Outcome.HANG));
      addTests(
          suite,
          method,