}
  }

  public enum ComparatorType {
    CHEAP {
      @Override
      public Comparator<Integer> get() {
        return Ordering.natural();
      }
    },
    EXPENSIVE {
      @Override
      public Comparator<Integer> get() {
        return Ordering.natural().onResultOf(new ExpensiveComputation());
      }
    };

    public abstract Comparator<Integer> get();
  }

@SuppressWarnings("JUnit4ClassUsedInJUnit3")
public class ListToArrayTester<E> extends AbstractListTester<E> {
  // CollectionToArrayTester tests everything except ordering.

  public void testToArray_noArg() {
    Object[] actual = getList().toArray();
    assertArrayEquals("toArray() order should match list", createOrderedArray(), actual);
  }

  @CollectionSize.Require(absent = ZERO)

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

  /**
   * Returns an immutable sorted set containing the given elements sorted by their natural ordering.
   * When multiple elements are equivalent according to {@code compareTo()}, only the first one

      K k1, V v1, K k2, V v2) {
    return new Builder<K, V>(Ordering.natural()).put(k1, v1).put(k2, v2).build();
  }

  public static <K extends Comparable<? super K>, V> ImmutableSortedMap<K, V> of(
      K k1, V v1, K k2, V v2, K k3, V v3) {
    return new Builder<K, V>(Ordering.natural()).put(k1, v1).put(k2, v2).put(k3, v3).build();
  }

    assertSame(Ordering.natural(), sortedTable.columnComparator());
    assertSame(
        Ordering.natural(),
        ((SortedMap<Integer, Character>) sortedTable.rowMap().values().iterator().next())
            .comparator());

    sortedTable = TreeBasedTable.create(Collections.reverseOrder(), Ordering.usingToString());
    sortedTable.put("", 42, 'x');

import java.io.Serializable;
import java.util.Iterator;

/** An ordering that uses the reverse of the natural order of the values. */
@GwtCompatible(serializable = true)
@SuppressWarnings({"unchecked", "rawtypes"}) // TODO(kevinb): the right way to explain this??
@ElementTypesAreNonnullByDefault
final class ReverseNaturalOrdering extends Ordering<Comparable<?>> implements Serializable {

import java.util.Comparator;
import javax.annotation.CheckForNull;
import org.checkerframework.checker.nullness.qual.Nullable;

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

  ComparatorOrdering(Comparator<T> comparator) {

  // ResourceRules is the list of actions the subject is allowed to perform on resources.
  // The list ordering isn't significant, may contain duplicates, and possibly be incomplete.
  repeated ResourceRule resourceRules = 1;

  // NonResourceRules is the list of actions the subject is allowed to perform on non-resources.
  // The list ordering isn't significant, may contain duplicates, and possibly be incomplete.

import java.io.Serializable;
import java.util.Iterator;

/** An ordering that uses the reverse of the natural order of the values. */
@GwtCompatible(serializable = true)
@SuppressWarnings({"unchecked", "rawtypes"}) // TODO(kevinb): the right way to explain this??
@ElementTypesAreNonnullByDefault
final class ReverseNaturalOrdering extends Ordering<Comparable<?>> implements Serializable {

   */
  private static final Comparator<?> NATURAL_ORDER = Ordering.natural();

  private static final ImmutableSortedMap<Comparable<?>, Object> NATURAL_EMPTY_MAP =
      new ImmutableSortedMap<>(
          ImmutableSortedSet.emptySet(Ordering.natural()), ImmutableList.<Object>of());

  static <K, V> ImmutableSortedMap<K, V> emptyMap(Comparator<? super K> comparator) {
    if (Ordering.natural().equals(comparator)) {
      return of();