* bufferSize ≥ k, then we can ignore any elements greater than this value.
   */
  private @Nullable T threshold;

  @SuppressWarnings("unchecked") // TODO(cpovirk): Consider storing Object[] instead of T[].
  private TopKSelector(Comparator<? super T> comparator, int k) {
    this.comparator = checkNotNull(comparator, "comparator");
    this.k = k;
    checkArgument(k >= 0, "k (%s) must be >= 0", k);

  Comparator<Object> unsafeComparator() {
    return (Comparator<Object>) comparator;
  }

  RegularImmutableSortedSet<E> getSubSet(int newFromIndex, int newToIndex) {
    if (newFromIndex == 0 && newToIndex == size()) {
      return this;
    } else if (newFromIndex < newToIndex) {
      return new RegularImmutableSortedSet<>(
          elements.subList(newFromIndex, newToIndex), comparator);
    } else {

 * Comparator} instead of {@code ComparisonChain}. The example above can be implemented like this:
 *
 * {@snippet :
 * import static java.util.Comparator.comparing;
 * import static java.util.Comparator.nullsLast;
 * import static java.util.Comparator.naturalOrder;
 *
 * ...
 *   private static final Comparator<Foo> COMPARATOR =
 *       comparing((Foo foo) -> foo.aString)

    /** Constructor for use by subclasses. */
    public StandardElementSet() {
      super(ForwardingSortedMultiset.this);
    }
  }

  @Override
  public Comparator<? super E> comparator() {
    return delegate().comparator();
  }

  @Override
  public SortedMultiset<E> descendingMultiset() {
    return delegate().descendingMultiset();
  }

  /**

  }

  @Override
  public void clear() {
    delegate.clear();
  }

  @Override
  public Comparator<? super K> comparator() {
    Comparator<? super K> comparator = delegate.comparator();
    if (comparator == null) {
      comparator = (Comparator<? super K>) NATURAL_ORDER;
    }
    return comparator;
  }

  @Override
  public boolean containsKey(Object key) {
    try {

   * the given {@code comparator}.
   *
   * @see #testComparator(Comparator, List)
   */
  public static <T extends @Nullable Object> void testComparator(
      Comparator<? super T> comparator, T... valuesInExpectedOrder) {
    testComparator(comparator, asList(valuesInExpectedOrder));
  }

  /**

    implements SortedMultiset<E> {
  private final Comparator<? super E> comparator;

  // needed for serialization
  @SuppressWarnings("unchecked")
  AbstractSortedMultiset() {
    this((Comparator) Ordering.natural());
  }

  AbstractSortedMultiset(Comparator<? super E> comparator) {
    this.comparator = checkNotNull(comparator);
  }

  @Override
  public NavigableSet<E> elementSet() {

  }

  @CollectionSize.Require(absent = ZERO)
  public void testOrderedByComparator() {
    Comparator<? super K> comparator = navigableMap.comparator();
    if (comparator == null) {
      comparator =
          new Comparator<K>() {
            @SuppressWarnings("unchecked")
            @Override
            public int compare(K o1, K o2) {

    assertEquals("a", elementSet.last());
    assertEquals(comparator, elementSet.comparator());
  }

  public void testNullAcceptingComparator() throws Exception {
    Comparator<@Nullable String> comparator = Ordering.<String>natural().<String>nullsFirst();
    TreeMultiset<@Nullable String> ms = TreeMultiset.create(comparator);

    ms.add("b");
    ms.add(null);
    ms.add("a");
    ms.add("b");

   * the given {@code comparator}.
   *
   * @see #testComparator(Comparator, List)
   */
  public static <T extends @Nullable Object> void testComparator(
      Comparator<? super T> comparator, T... valuesInExpectedOrder) {
    testComparator(comparator, asList(valuesInExpectedOrder));
  }

  /**