* there is no need to use this method.
   *
   * @param comparator the comparator that defines the order
   * @return comparator itself if it is already an {@code Ordering}; otherwise an ordering that
   *     wraps that comparator
   */
  @GwtCompatible(serializable = true)
  public static <T extends @Nullable Object> Ordering<T> from(Comparator<T> comparator) {
    return (comparator instanceof Ordering)
        ? (Ordering<T>) comparator

            .comparator());
  }

  public void testRowKeySetComparator() {
    sortedTable = TreeBasedTable.create();
    assertSame(Ordering.natural(), sortedTable.rowKeySet().comparator());

    sortedTable = TreeBasedTable.create(Collections.reverseOrder(), Ordering.usingToString());
    assertSame(Collections.reverseOrder(), sortedTable.rowKeySet().comparator());
  }

            new byte[] {GREATEST, GREATEST, GREATEST});

    Comparator<byte[]> comparator = SignedBytes.lexicographicalComparator();
    Helpers.testComparator(comparator, ordered);
  }

  @J2ktIncompatible
  @GwtIncompatible // SerializableTester
  public void testLexicographicalComparatorSerializable() {
    Comparator<byte[]> comparator = SignedBytes.lexicographicalComparator();

    assertEquals(multimap, copy);
  }

  private static final Comparator<Double> KEY_COMPARATOR = Ordering.natural();

  private static final Comparator<Double> VALUE_COMPARATOR =
      Ordering.<Double>natural().reverse().nullsFirst();

  /**
   * Test that creating one TreeMultimap from another does not copy the comparators from the source
   * TreeMultimap.
   */
  public void testCreateFromTreeMultimap() {

    assertThat(network.nodes()).containsExactly(4, 1, 3);
  }

  // Sorting of user-defined classes

  @Test
  public void customComparator() {
    Comparator<NonComparableSuperClass> comparator =
        new Comparator<NonComparableSuperClass>() {
          @Override
          public int compare(NonComparableSuperClass left, NonComparableSuperClass right) {
            return left.value.compareTo(right.value);

        }

        @Override
        public <T extends @Nullable Object> ComparisonChain compare(
            @ParametricNullness T left, @ParametricNullness T right, Comparator<T> comparator) {
          return classify(comparator.compare(left, right));
        }

        @Override
        public ComparisonChain compare(int left, int right) {
          return classify(Ints.compare(left, right));
        }

  }

  public void testCreation_arrayOfArray() {
    Comparator<String[]> comparator =
        Ordering.natural().lexicographical().onResultOf(Arrays::asList);
    String[] array = new String[] {"a"};
    Multiset<String[]> multiset = ImmutableSortedMultiset.orderedBy(comparator).add(array).build();
    Multiset<String[]> expected = HashMultiset.create();
    expected.add(array);

    /** 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();
  }

  /**

/**
 * Tests for {@code Comparators}.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@ElementTypesAreNonnullByDefault
public class ComparatorsTest extends TestCase {
  public void testLexicographical() {
    Comparator<String> comparator = Ordering.natural();
    Comparator<Iterable<String>> lexy = Comparators.lexicographical(comparator);

    ImmutableList<String> empty = ImmutableList.of();

    checkUnbounded(queue);
    checkNatural(queue);
  }

  public void testCreation_comparator() {
    MinMaxPriorityQueue<Integer> queue = MinMaxPriorityQueue.orderedBy(SOME_COMPARATOR).create();
    assertEquals(11, queue.capacity());
    checkUnbounded(queue);
    assertSame(SOME_COMPARATOR, queue.comparator());
  }

  // We use the rawtypeToWildcard "cast" to make the test work with J2KT in other tests. Leaving one