* @since 20.0
 */
@J2ktIncompatible
@GwtIncompatible
@ElementTypesAreNonnullByDefault
public final class StatsAccumulator {

  // These fields must satisfy the requirements of Stats' constructor as well as those of the stat
  // methods of this class.
  private long count = 0;
  private double mean = 0.0; // any finite value will do, we only use it to multiply by zero for sum
  private double sumOfSquaresOfDeltas = 0.0;

    return xStats.count();
  }

  /** Returns an immutable snapshot of the statistics on the {@code x} values alone. */
  public Stats xStats() {
    return xStats.snapshot();
  }

  /** Returns an immutable snapshot of the statistics on the {@code y} values alone. */
  public Stats yStats() {
    return yStats.snapshot();
  }

  /**
   * Returns the population covariance of the values. The count must be non-zero.

 * frac(x) respectively. This is the same definition as used by Excel and by S, it is the Type 7
 * definition in <a
 * href="http://stat.ethz.ch/R-manual/R-devel/library/stats/html/quantile.html">R</a>, and it is
 * described by <a
 * href="http://en.wikipedia.org/wiki/Quantile#Estimating_the_quantiles_of_a_population">

    assertThat(manager.servicesByState().keySet()).containsExactly(Service.State.FAILED);
  }

  private static void assertState(
      ServiceManager manager, Service.State state, Service... services) {
    Collection<Service> managerServices = manager.servicesByState().get(state);
    for (Service service : services) {
      assertEquals(service.toString(), state, service.state());

      // Iterate through the parts of the ip string.
      // Invariant: start is always the beginning of a hextet, or the second ':' of the skip
      // sequence "::"
      int start = 0;
      if (ipString.charAt(0) == IPV6_DELIMITER) {
        start = 1;
      }
      while (start < ipString.length()) {
        int end = ipString.indexOf(IPV6_DELIMITER, start);
        if (end == -1) {
          end = ipString.length();

  public TestThread(L lockLikeObject, String threadName) {
    super(threadName);
    this.lockLikeObject = checkNotNull(lockLikeObject);
    start();
  }

  // Thread.stop() is okay because all threads started by a test are dying at the end of the test,
  // so there is no object state put at risk by stopping the threads abruptly. In some cases a test

  private static final Logger log = Logger.getLogger(AbstractFuture.class.getName());

  private State state;
  private V value;
  private @Nullable Future<? extends V> delegate;
  private @Nullable Throwable throwable;
  private boolean mayInterruptIfRunning;
  private List<Listener> listeners;

  protected AbstractFuture() {
    state = State.PENDING;
    listeners = new ArrayList<Listener>();
  }

  @CanIgnoreReturnValue

    checkState(state != State.FAILED);
    switch (state) {
      case DONE:
        return false;
      case READY:
        return true;
      default:
    }
    return tryToComputeNext();
  }

  private boolean tryToComputeNext() {
    state = State.FAILED; // temporary pessimism
    next = computeNext();
    if (state != State.DONE) {
      state = State.READY;
      return true;
    }

    final byte[] array;
    final int start;
    final int end;

    ByteArrayAsList(byte[] array) {
      this(array, 0, array.length);
    }

    ByteArrayAsList(byte[] array, int start, int end) {
      this.array = array;
      this.start = start;
      this.end = end;
    }

    @Override
    public int size() {
      return end - start;
    }

    @Override

        AggregateFutureState<?> state, @CheckForNull Set<Throwable> expect, Set<Throwable> update) {
      synchronized (state) {
        if (state.seenExceptions == expect) {
          state.seenExceptions = update;
        }
      }
    }

    @Override
    int decrementAndGetRemainingCount(AggregateFutureState<?> state) {
      synchronized (state) {
        return --state.remaining;
      }