}

    private int reverseIndex(int index) {
      int size = size();
      checkElementIndex(index, size);
      return (size - 1) - index;
    }

    private int reversePosition(int index) {
      int size = size();
      checkPositionIndex(index, size);
      return size - index;
    }

    @Override
    public void add(int index, @ParametricNullness T element) {

    /**
     * Writes the given suggest items to the specified index.
     *
     * @param client   the client used to interact with the search engine
     * @param settings the settings for the suggest feature
     * @param index    the name of the index where the suggest items will be written
     * @param items    an array of suggest items to be written to the index

    });
```

## Advanced Usage

### Index from Existing Documents

```java
import org.codelibs.fess.suggest.index.contents.document.ESSourceReader;

// Index suggestions from existing Elasticsearch documents
DocumentReader reader = new ESSourceReader(
    client,
    suggester.settings(),
    "content-index",        // source index
    "document"             // document type
);

    public @Nullable V get(@Nullable Object key) {
      Integer index = keyIndex.get(key);
      if (index == null) {
        return null;
      } else {
        return getValue(index);
      }
    }

    @Override
    public @Nullable V put(K key, @ParametricNullness V value) {
      Integer index = keyIndex.get(key);
      if (index == null) {
        throw new IllegalArgumentException(

import org.elasticsearch.core.Releasables;
import org.elasticsearch.index.Index;
import org.elasticsearch.index.IndexSettings;
import org.elasticsearch.index.analysis.NamedAnalyzer;
import org.elasticsearch.index.cache.bitset.BitsetFilterCache;
import org.elasticsearch.index.fielddata.IndexFieldData;
import org.elasticsearch.index.fielddata.IndexFieldDataCache;
import org.elasticsearch.index.mapper.MappedFieldType;

    /**
     * Specifies a single quantile index to be calculated, i.e. the k in the kth q-quantile.
     *
     * @param index the quantile index, which must be in the inclusive range [0, q] for q-quantiles
     */
    public ScaleAndIndex index(int index) {
      return new ScaleAndIndex(scale, index);
    }

    /**
     * Specifies multiple quantile indexes to be calculated, each index being the k in the kth
     * q-quantile.

    }

    /**
     * Encodes a String as UTF-8 bytes.
     *
     * @param str the String to encode
     * @param dst the destination byte array
     * @param di the starting index in the destination array
     * @param dlim the maximum index in the destination array
     * @return the number of bytes written
     */
    public static int enc_utf8(final String str, final byte[] dst, int di, final int dlim) {

        private int index = -1;
        private final int maxIndex = keyToIndex().size();

        @Override
        protected @Nullable Entry<K, V> computeNext() {
          for (index++; index < maxIndex; index++) {
            V value = getValue(index);
            if (value != null) {
              return immutableEntry(getKey(index), value);
            }
          }

import org.opensearch.index.query.MoreLikeThisQueryBuilder;
import org.opensearch.index.query.PrefixQueryBuilder;
import org.opensearch.index.query.QueryBuilder;
import org.opensearch.index.query.QueryBuilders;
import org.opensearch.index.query.QueryStringQueryBuilder;
import org.opensearch.index.query.RangeQueryBuilder;
import org.opensearch.index.query.RegexpQueryBuilder;
import org.opensearch.index.query.SpanTermQueryBuilder;

        PopularWordsResponse response = new PopularWordsResponse("my-index", 50, words, 5, new ArrayList<>());

        assertEquals("my-index", response.getIndex());
    }

    @Test
    public void test_getTookMs() throws Exception {
        List<String> words = new ArrayList<>();
        PopularWordsResponse response = new PopularWordsResponse("test-index", 123, words, 5, new ArrayList<>());