public void testFutureGetThrowsCancellationIfOutputCancelled() throws Exception {
    inputFuture.set(SLOW_OUTPUT_VALID_INPUT_DATA);
    outputFuture.cancel(true); // argument is ignored
    assertThrows(CancellationException.class, () -> resultFuture.get());
  }

  public void testAsyncToString() throws Exception {
    inputFuture.set(SLOW_OUTPUT_VALID_INPUT_DATA);
    assertThat(resultFuture.toString()).contains(outputFuture.toString());
  }

 * @since 11.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public interface AsyncFunction<I extends @Nullable Object, O extends @Nullable Object> {
  /**
   * Returns an output {@code Future} to use in place of the given {@code input}. The output {@code
   * Future} need not be {@linkplain Future#isDone done}, making {@code AsyncFunction} suitable for
   * asynchronous derivations.
   *

      // requireNonNull is safe because of the hasNext check.
      BiEntry<K, V> entry = requireNonNull(next);
      next = entry.nextInKeyInsertionOrder;
      toRemove = entry;
      remaining--;
      return output(entry);
    }

    @Override
    public void remove() {
      if (modCount != expectedModCount) {
        throw new ConcurrentModificationException();
      }
      if (toRemove == null) {

   * char} are hashed directly (in that order). The input must not be updated while this method is
   * in progress.
   *
   * <p><b>Warning:</b> This method will produce different output than most other languages do when
   * running the same hash function on the equivalent input. For cross-language compatibility, use
   * {@link #putString}, usually with a charset of UTF-8. For other use cases, use {@code

   * Multimap} entries in two distinct modes:
   *
   * <ul>
   *   <li>To output a separate entry for each key-value pair, pass {@code multimap.entries()} to a
   *       {@code MapJoiner} method that accepts entries as input, and receive output of the form
   *       {@code key1=A&key1=B&key2=C}.
   *   <li>To output a single entry for each key, pass {@code multimap.asMap()} to a {@code

 * result.
 *
 * @since 20.0
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public interface AsyncCallable<V extends @Nullable Object> {
  /**
   * Computes a result {@code Future}. The output {@code Future} need not be {@linkplain
   * Future#isDone done}, making {@code AsyncCallable} suitable for asynchronous derivations.
   *
   * <p>Throwing an exception from this method is equivalent to returning a failing {@link

  }

  @Override
  public boolean wasStreamClosed() {
    return byteSink.wasStreamClosed();
  }

  @Override
  public Writer openStream() throws IOException {
    // using TestByteSink's output stream to get option behavior, so flush to it on every write
    return new FilterWriter(new OutputStreamWriter(byteSink.openStream(), UTF_8)) {
      @Override
      public void write(int c) throws IOException {

   * primary input succeeds, it is never invoked. If, during the invocation of {@code fallback}, an
   * exception is thrown, this exception is used as the result of the output {@code Future}.
   *
   * <p>Usage example:
   *
   * <pre>{@code
   * // Falling back to a zero counter in case an exception happens when processing the RPC to fetch
   * // counters.

    return newReentrantLock(lockName, false);
  }

  /**
   * Creates a {@link ReentrantLock} with the given fairness policy. The {@code lockName} is used in
   * the warning or exception output to help identify the locks involved in the detected deadlock.
   */
  public ReentrantLock newReentrantLock(String lockName, boolean fair) {
    return policy == Policies.DISABLED
        ? new ReentrantLock(fair)

    return builder;
  }

  /**
   * Returns a string that can be used to parse an equivalent {@code CacheBuilderSpec}. The order
   * and form of this representation is not guaranteed, except that reparsing its output will
   * produce a {@code CacheBuilderSpec} equal to this instance.
   */
  public String toParsableString() {
    return specification;
  }

  /**