*   <li>SORTED: ordering according to a supplied comparator is guaranteed.
   * </ul>
   */
  public enum Type {
    UNORDERED,
    STABLE,
    INSERTION,
    SORTED
  }

  private ElementOrder(Type type, @Nullable Comparator<T> comparator) {
    this.type = checkNotNull(type);
    this.comparator = comparator;
    checkState((type == Type.SORTED) == (comparator != null));
  }

   *   <li>SORTED: ordering according to a supplied comparator is guaranteed.
   * </ul>
   */
  public enum Type {
    UNORDERED,
    STABLE,
    INSERTION,
    SORTED
  }

  private ElementOrder(Type type, @Nullable Comparator<T> comparator) {
    this.type = checkNotNull(type);
    this.comparator = comparator;
    checkState((type == Type.SORTED) == (comparator != null));
  }

import java.io.Serializable;
import java.util.Comparator;
import org.jspecify.annotations.Nullable;

/** An ordering for a pre-existing comparator. */
@GwtCompatible
final class ComparatorOrdering<T extends @Nullable Object> extends Ordering<T>
    implements Serializable {
  final Comparator<T> comparator;

  ComparatorOrdering(Comparator<T> comparator) {
    this.comparator = checkNotNull(comparator);
  }

  @Override

    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");

import static java.lang.Integer.signum;
import static java.util.Comparator.comparing;
import static java.util.Comparator.naturalOrder;
import static java.util.Comparator.nullsLast;

import com.google.common.annotations.GwtCompatible;
import com.google.common.annotations.J2ktIncompatible;
import com.google.common.primitives.Booleans;
import java.util.Comparator;
import junit.framework.AssertionFailedError;

    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");

  private final transient long[] cumulativeCounts;
  private final transient int offset;
  private final transient int length;

  RegularImmutableSortedMultiset(Comparator<? super E> comparator) {
    this.elementSet = ImmutableSortedSet.emptySet(comparator);
    this.cumulativeCounts = zeroCumulativeCounts;
    this.offset = 0;
    this.length = 0;
  }

  RegularImmutableSortedMultiset(

          Comparator<? super E> comparator,
          @ParametricNullness E key,
          List<? extends E> list,
          int foundIndex) {
        return FIRST_PRESENT.resultIndex(comparator, key, list, foundIndex) - 1;
      }
    };

    abstract <E extends @Nullable Object> int resultIndex(
        Comparator<? super E> comparator,
        @ParametricNullness E key,

    Ordering<@Nullable Object> comparator = Ordering.allEqual();
    assertSame(comparator, comparator.reverse());

    assertEquals(0, comparator.compare(null, null));
    assertEquals(0, comparator.compare(new Object(), new Object()));
    assertEquals(0, comparator.compare("apples", "oranges"));
    assertSame(comparator, reserialize(comparator));
    assertEquals("Ordering.allEqual()", comparator.toString());

    Ordering<@Nullable Object> comparator = Ordering.allEqual();
    assertSame(comparator, comparator.reverse());

    assertEquals(0, comparator.compare(null, null));
    assertEquals(0, comparator.compare(new Object(), new Object()));
    assertEquals(0, comparator.compare("apples", "oranges"));
    assertSame(comparator, reserialize(comparator));
    assertEquals("Ordering.allEqual()", comparator.toString());