+ (longWait ? "3" : "1")
                + " seconds, "
                + nanosRegex
                + " nanoseconds delay\\).*");
  }

  public void testToString_completed() throws Exception {
    AbstractFuture<Object> testFuture2 =
        new AbstractFuture<Object>() {
          @Override
          public String pendingToString() {
            return "cause=[Someday...]";

  }

  /** CASes the busy field from 0 to 1 to acquire lock. */
  final boolean casBusy() {
    return UNSAFE.compareAndSwapInt(this, busyOffset, 0, 1);
  }

  /**
   * Computes the function of current and new value. Subclasses should open-code this update
   * function for most uses, but the virtualized form is needed within retryUpdate.
   *

  //      */
  //     public abstract class CheckedRecursiveAction extends RecursiveAction {
  //         protected abstract void realCompute() throws Throwable;

  //         public final void compute() {
  //             try {
  //                 realCompute();
  //             } catch (Throwable t) {
  //                 threadUnexpectedException(t);
  //             }
  //         }
  //     }

    ListenableFuture<Integer> immediateFuture = immediateFuture(4);
    Future<Integer> transformedFuture = transform(immediateFuture, adder, directExecutor());

    // The composed future also yields 6.
    assertEquals(6, getDone(transformedFuture).intValue());

    // Repeated calls yield the same value even though the function's behavior
    // changes
    holder.value = 3;

    assertEquals(expectedMean, IntMath.mean(x, y));
    assertEquals(
        "The mean of x and y should equal the mean of y and x", expectedMean, IntMath.mean(y, x));
  }

  /**
   * Computes the mean in a way that is obvious and resilient to overflow by using BigInteger
   * arithmetic.
   */
  private static int computeMeanSafely(int x, int y) {
    BigInteger bigX = BigInteger.valueOf(x);

       *   either this Future was cancelled (which we ruled out with the isCancelled check above),
       *   or it had already failed. (It couldn't have completed *successfully* or even had
       *   setFuture called on it: Neither of those can happen until we've finished processing all
       *   the completed inputs. And we're still processing at least one input, the one that
       *   triggered handleException.)
       *

        this.bitsPerChar = log2(chars.length, UNNECESSARY);
      } catch (ArithmeticException e) {
        throw new IllegalArgumentException("Illegal alphabet length " + chars.length, e);
      }

      // Compute how input bytes are chunked. For example, with base64 we chunk every 3 bytes into
      // 4 characters. We have bitsPerChar == 6, charsPerChunk == 4, and bytesPerChunk == 3.

   *
   * <p><i>Notes:</i> This is an implementation of the algorithm for Lexicographical Permutations
   * Generation, described in Knuth's "The Art of Computer Programming", Volume 4, Chapter 7,
   * Section 7.2.1.2. The iteration order follows the lexicographical order. This means that the
   * first permutation will be in ascending order, and the last will be in descending order.
   *

 * iteratorTester.testForEachRemaining();
 * }</pre>
 *
 * <p><b>Note</b>: It is necessary to use {@code IteratorTester.KnownOrder} as shown above, rather
 * than {@code KnownOrder} directly, because otherwise the code cannot be compiled.
 *
 * @author Kevin Bourrillion
 * @author Chris Povirk
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public abstract class IteratorTester<E extends @Nullable Object>

abstract class AggregateFutureState<OutputT extends @Nullable Object>
    extends AbstractFuture.TrustedFuture<OutputT> {
  // Lazily initialized the first time we see an exception; not released until all the input futures
  // have completed and we have processed them all.
  @CheckForNull private volatile Set<Throwable> seenExceptions = null;

  private volatile int remaining;

  private static final AtomicHelper ATOMIC_HELPER;