import java.util.ArrayList;
import java.util.List;

/**
 * The NormalizerChain class implements the Normalizer interface and allows chaining multiple normalizers together.
 * It applies each normalizer in the order they were added to the chain.
 *
 * <p>Usage example:</p>
 * <pre>
 * NormalizerChain chain = new NormalizerChain();
 * chain.add(new SomeNormalizer());
 * chain.add(new AnotherNormalizer());

public class NormalizerChainTest {

    @Test
    public void test_constructor() throws Exception {
        NormalizerChain chain = new NormalizerChain();
        assertNotNull(chain);
    }

    @Test
    public void test_singleNormalizer() throws Exception {
        NormalizerChain chain = new NormalizerChain();
        chain.add(new FullWidthToHalfWidthAlphabetNormalizer());

        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));
            }
            normalizer = chain;
        }

└── util/                      # Utilities
```

### Key Design Patterns

- **Builder**: SuggesterBuilder, SuggestRequestBuilder
- **Facade**: Suggester (main entry point)
- **Composite**: NormalizerChain, ReadingConverterChain
- **Strategy**: Normalizer, ReadingConverter, ContentsParser
- **Deferred/Promise**: Async operations

### Index Alias Strategy

Zero-downtime index updates using dual aliases:

```