* A mutable value of type {@code int}, for multisets to use in tracking counts of values.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
final class Count implements Serializable {
  private int value;

  Count(int value) {
    this.value = value;
  }

  public int get() {
    return value;
  }

  public void add(int delta) {
    value += delta;
  }

        @SuppressWarnings("unchecked") // we only put Ts in it
        @Nullable
        T[] array = (@Nullable T[]) new Object[size];
        int count = 0;
        for (; count < size && iterator.hasNext(); count++) {
          array[count] = iterator.next();
        }
        for (int i = count; i < size; i++) {
          array[i] = null; // for GWT
        }

    AtomicInteger initial = new AtomicInteger(INITIAL_COUNT);
    when(backingMap.get(KEY)).thenReturn(initial);

    assertEquals(INITIAL_COUNT, multiset.add(KEY, COUNT_TO_ADD));
    assertEquals(INITIAL_COUNT + COUNT_TO_ADD, initial.get());
  }

  public void testAdd_laterFewWithOverflow() {
    final int INITIAL_COUNT = 92384930;
    final int COUNT_TO_ADD = Integer.MAX_VALUE - INITIAL_COUNT + 1;

  }

  public void testAddAndGet() {
    Count holder = new Count(20);
    assertEquals(21, holder.addAndGet(1));
  }

  public void testGetAndSet() {
    Count holder = new Count(10);
    assertEquals(10, holder.getAndSet(20));
    assertEquals(20, holder.get());
  }

  public void testSet() {
    Count holder = new Count(10);
    holder.set(20);
    assertEquals(20, holder.get());
  }

  public void testAddOccurrences() {
    int originalCount = getMultiset().count(e0());
    assertEquals("old count", originalCount, getMultiset().add(e0(), 2));
    assertEquals("old count", originalCount + 2, getMultiset().count(e0()));
  }

  @CollectionFeature.Require(SUPPORTS_ADD)
  public void testAddSeveralTimes() {
    int originalCount = getMultiset().count(e0());
    assertEquals(originalCount, getMultiset().add(e0(), 2));

  void setCountCheckReturnValue(E element, int count) {
    assertEquals(
        "multiset.setCount() should return the old count",
        getMultiset().count(element),
        setCount(element, count));
  }

  @Override
  void setCountNoCheckReturnValue(E element, int count) {
    setCount(element, count);
  }

  @CanIgnoreReturnValue
  private int setCount(E element, int count) {

                  * values.count();
    }
    yStats.addAll(values.yStats());
  }

  /** Returns an immutable snapshot of the current statistics. */
  public PairedStats snapshot() {
    return new PairedStats(xStats.snapshot(), yStats.snapshot(), sumOfProductsOfDeltas);
  }

  /** Returns the number of pairs in the dataset. */
  public long count() {
    return xStats.count();
  }

  @Override
  public int setCount(E element, int count) {
    checkIsE(element);
    checkNonnegative(count, "count");
    int index = element.ordinal();
    int oldCount = counts[index];
    counts[index] = count;
    size += count - oldCount;
    if (oldCount == 0 && count > 0) {
      distinctElements++;
    } else if (oldCount > 0 && count == 0) {
      distinctElements--;
    }
    return oldCount;

    List<Entry<E>> expected = new ArrayList<>(getMultiset().entrySet());
    List<Entry<E>> actual = new ArrayList<>();
    getMultiset()
        .forEachEntry((element, count) -> actual.add(Multisets.immutableEntry(element, count)));
    Helpers.assertEqualIgnoringOrder(expected, actual);
  }

  @CollectionFeature.Require(KNOWN_ORDER)
  public void testForEachEntryOrdered() {

      // The JVM will return interned values for small ints.
      Integer value = random.nextInt(1000) + 128;
      int count = Math.min(random.nextInt(10) + 1, sizeRemaining);
      sizeRemaining -= count;
      hashMultiset.add(value, count);
      linkedHashMultiset.add(value, count);
      treeMultiset.add(value, count);
    }

    // TODO(kevinb): convert to assert once benchmark tests enable asserts by default