import com.google.common.collect.Ordering;
import com.google.errorprone.annotations.Immutable;
import java.util.Comparator;
import java.util.Map;
import java.util.Objects;
import org.jspecify.annotations.Nullable;

/**
 * Used to represent the order of elements in a data structure that supports different options for
 * iteration order guarantees.
 *
 * <p>Example usage:
 *
 * {@snippet :

   * range [0, k) and ignore the remaining elements.
   */
  private final @Nullable T[] buffer;
  private int bufferSize;

  /**
   * The largest of the lowest k elements we've seen so far relative to this comparator. If
   * bufferSize ≥ k, then we can ignore any elements greater than this value.
   */
  private @Nullable T threshold;

@GwtIncompatible
@J2ktIncompatible
interface ReferenceEntry<K, V> {
  /** Returns the value reference from this entry. */
  @Nullable ValueReference<K, V> getValueReference();

  /** Sets the value reference for this entry. */
  void setValueReference(ValueReference<K, V> valueReference);

  /** Returns the next entry in the chain. */
  @Nullable ReferenceEntry<K, V> getNext();

  /** Returns the entry's hash. */
  int getHash();

   * Tests that {@code cls} properly checks null on all constructor and method parameters that
   * aren't annotated nullable (according to the rules of {@link NullPointerTester}). In details:
   *
   * <ul>
   *   <li>All non-private static methods are checked such that passing null for any parameter
   *       that's not annotated nullable should throw {@link NullPointerException}.

    Object value = new Object();
    Callable<Object> callable = Callables.returning(value);
    assertThat(callable.call()).isEqualTo(value);
    // Expect the same value on subsequent calls
    assertThat(callable.call()).isEqualTo(value);
  }

  @J2ktIncompatible
  @GwtIncompatible
  public void testAsAsyncCallable() throws Exception {
    String expected = "MyCallableString";
    Callable<String> callable = () -> expected;

    Object value = new Object();
    Callable<Object> callable = Callables.returning(value);
    assertThat(callable.call()).isEqualTo(value);
    // Expect the same value on subsequent calls
    assertThat(callable.call()).isEqualTo(value);
  }

  @J2ktIncompatible
  @GwtIncompatible
  public void testAsAsyncCallable() throws Exception {
    String expected = "MyCallableString";
    Callable<String> callable = () -> expected;

import com.google.errorprone.annotations.CanIgnoreReturnValue;
import org.jspecify.annotations.Nullable;

/** Precondition checks useful in collection implementations. */
@GwtCompatible
final class CollectPreconditions {

  static void checkEntryNotNull(@Nullable Object key, @Nullable Object value) {
    if (key == null) {
      throw new NullPointerException("null key in entry: null=" + value);

   * @return a {@code BloomFilter}
   * @since 19.0
   */
  public static <T extends @Nullable Object> BloomFilter<T> create(
      Funnel<? super T> funnel, long expectedInsertions, double fpp) {
    return create(funnel, expectedInsertions, fpp, BloomFilterStrategies.MURMUR128_MITZ_64);
  }

  @VisibleForTesting
  static <T extends @Nullable Object> BloomFilter<T> create(

import java.util.Map.Entry;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Creates multimaps, containing sample elements, to be tested.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@NullMarked
public interface TestMultimapGenerator<
        K extends @Nullable Object, V extends @Nullable Object, M extends Multimap<K, V>>
    extends TestContainerGenerator<M, Entry<K, V>> {

import java.util.Map.Entry;
import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Creates multimaps, containing sample elements, to be tested.
 *
 * @author Louis Wasserman
 */
@GwtCompatible
@NullMarked
public interface TestMultimapGenerator<
        K extends @Nullable Object, V extends @Nullable Object, M extends Multimap<K, V>>
    extends TestContainerGenerator<M, Entry<K, V>> {