return client.index(request);
    }

    /**
     * Executes an index request asynchronously.
     *
     * @param request The index request.
     * @param listener The response listener.
     */
    @Override
    public void index(final IndexRequest request, final ActionListener<IndexResponse> listener) {
        client.index(request, listener);
    }

    /**

    // Call the next interceptor in the chain.
    val next = copy(index = index + 1, request = request)
    val interceptor = interceptors[index]

    @Suppress("USELESS_ELVIS")
    val response =
      interceptor.intercept(next) ?: throw NullPointerException(
        "interceptor $interceptor returned null",
      )

    if (exchange != null) {
      check(index + 1 >= interceptors.size || next.calls == 1) {

    }

    @Override
    public int indexOf(@Nullable Object object) {
      int index = forwardList.lastIndexOf(object);
      return (index >= 0) ? reverseIndex(index) : -1;
    }

    @Override
    public int lastIndexOf(@Nullable Object object) {
      int index = forwardList.indexOf(object);
      return (index >= 0) ? reverseIndex(index) : -1;
    }

    @Override

    int startingIndex = smear(c) & mask;
    int index = startingIndex;
    do {
      if (table[index] == 0) { // Check for empty.
        return false;
      } else if (table[index] == c) { // Check for match.
        return true;
      } else { // Linear probing.
        index = (index + 1) & mask;
      }
      // Check to see if we wrapped around the whole table.
    } while (index != startingIndex);
    return false;
  }

     */
    public int getIndex() {
        return this.index;
    }

    /**
     * Sets the current index position in the buffer.
     *
     * @param index the new index position
     */
    public void setIndex(final int index) {
        this.index = index;
    }

    /**
     * Returns the capacity of the buffer.
     *
     * @return the buffer capacity
     */

    });
```

## 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
);

    }

    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) {

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;

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;

     */
    protected int filterReplicas = 1;

    /**
     * Returns the queue index name.
     * @return The queue index name.
     */
    public String getQueueIndex() {
        return queueIndex;
    }

    /**
     * Sets the queue index name.
     * @param queueIndex The queue index name.
     */
    public void setQueueIndex(final String queueIndex) {
        this.queueIndex = queueIndex;
    }