replacement = "checkNotNull(ordering)",
      staticImports = "com.google.common.base.Preconditions.checkNotNull")
  @Deprecated
  public static <T extends @Nullable Object> Ordering<T> from(Ordering<T> ordering) {
    return checkNotNull(ordering);
  }

  /**
   * Returns an ordering that compares objects according to the order in which they appear in the

      implements TestSetGenerator<UnhashableObject> {}

  private static Ordering<String> createExplicitComparator(String[] elements) {
    // Collapse equal elements, which Ordering.explicit() doesn't support, while
    // maintaining the ordering by first occurrence.
    Set<String> elementsPlus = new LinkedHashSet<>();
    elementsPlus.add(BEFORE_FIRST);

 * @author Kevin Bourrillion
 * @author Ben Yu
 * @since 12.0
 */
@GwtIncompatible
@J2ktIncompatible
@NullMarked
public final class ArbitraryInstances {

  private static final Ordering<Field> BY_FIELD_NAME =
      new Ordering<Field>() {
        @Override
        public int compare(Field left, Field right) {
          return left.getName().compareTo(right.getName());
        }
      };

  /**

import org.jspecify.annotations.Nullable;

/**
 * An ordering that orders elements by applying an order to the result of a function on those
 * elements.
 */
@GwtCompatible
final class ByFunctionOrdering<F extends @Nullable Object, T extends @Nullable Object>
    extends Ordering<F> implements Serializable {
  final Function<F, ? extends T> function;
  final Ordering<T> ordering;

    testComparator(arbitrary, list);
  }

  public void testUsingToString() {
    Ordering<Object> ordering = Ordering.usingToString();
    testComparator(ordering, 1, 12, 124, 2);
    assertEquals("Ordering.usingToString()", ordering.toString());
    assertSame(ordering, reserialize(ordering));
  }

  // use an enum to get easy serializability

    testComparator(arbitrary, list);
  }

  public void testUsingToString() {
    Ordering<Object> ordering = Ordering.usingToString();
    testComparator(ordering, 1, 12, 124, 2);
    assertEquals("Ordering.usingToString()", ordering.toString());
    assertSame(ordering, reserialize(ordering));
  }

  // use an enum to get easy serializability

    // Unsafe, see ImmutableSortedMultisetFauxverideShim.
    @SuppressWarnings("unchecked")
    Ordering<E> naturalOrder = (Ordering<E>) Ordering.<Comparable<?>>natural();
    return copyOf(naturalOrder, elements);
  }

  /**
   * Returns an immutable sorted multiset containing the given elements sorted by their natural
   * ordering.
   *
   * <p>This method is not type-safe, as it may be called on elements that are not mutually

      GeneralRange<@Nullable Integer> range = GeneralRange.downTo(ORDERING, 3, lBoundType);
      for (Integer i : IN_ORDER_VALUES) {
        assertEquals(
            ORDERING.compare(i, 3) > 0 || (ORDERING.compare(i, 3) == 0 && lBoundType == CLOSED),
            range.contains(i));
        assertEquals(
            ORDERING.compare(i, 3) < 0 || (ORDERING.compare(i, 3) == 0 && lBoundType == OPEN),
            range.tooLow(i));

      GeneralRange<@Nullable Integer> range = GeneralRange.downTo(ORDERING, 3, lBoundType);
      for (Integer i : IN_ORDER_VALUES) {
        assertEquals(
            ORDERING.compare(i, 3) > 0 || (ORDERING.compare(i, 3) == 0 && lBoundType == CLOSED),
            range.contains(i));
        assertEquals(
            ORDERING.compare(i, 3) < 0 || (ORDERING.compare(i, 3) == 0 && lBoundType == OPEN),
            range.tooLow(i));

import org.jspecify.annotations.Nullable;

/**
 * An ordering that orders elements by applying an order to the result of a function on those
 * elements.
 */
@GwtCompatible
final class ByFunctionOrdering<F extends @Nullable Object, T extends @Nullable Object>
    extends Ordering<F> implements Serializable {
  final Function<F, ? extends T> function;
  final Ordering<T> ordering;