public Comparator<? super Cut<C>> comparator() {
      return Ordering.<Cut<C>>natural();
    }

    @Override
    public boolean containsKey(@Nullable Object key) {
      return get(key) != null;
    }

    @Override
    public @Nullable Range<C> get(@Nullable Object key) {
      if (key instanceof Cut) {
        try {
          @SuppressWarnings("unchecked") // we catch CCEs
          Cut<C> cut = (Cut<C>) key;

    READY,
    NOT_READY,
    DONE,
    FAILED,
  }

  private @Nullable T next;

  protected abstract @Nullable T computeNext();

  @CanIgnoreReturnValue
  protected final @Nullable T endOfData() {
    state = State.DONE;
    return null;
  }

  @Override
  public final boolean hasNext() {
    checkState(state != State.FAILED);
    switch (state) {
      case DONE:
        return false;

    return new TreeRow(rowKey);
  }

  private final class TreeRow extends Row implements SortedMap<C, V> {
    final @Nullable C lowerBound;
    final @Nullable C upperBound;

    TreeRow(R rowKey) {
      this(rowKey, null, null);
    }

    TreeRow(R rowKey, @Nullable C lowerBound, @Nullable C upperBound) {
      super(rowKey);
      this.lowerBound = lowerBound;
      this.upperBound = upperBound;

   *
   * <p>The serialized output consists of the number of entries, first key, first value, second key,
   * second value, and so on.
   */
  static <K extends @Nullable Object, V extends @Nullable Object> void writeMap(
      Map<K, V> map, ObjectOutputStream stream) throws IOException {
    stream.writeInt(map.size());
    for (Map.Entry<K, V> entry : map.entrySet()) {

    public static Object good(
        String a,
        int b,
        // oneConstantOnly doesn't matter since it's not nullable and can be only 1 value.
        @SuppressWarnings("unused") OneConstantEnum oneConstantOnly,
        // noConstant doesn't matter since it can only be null
        @SuppressWarnings("unused") @Nullable NoConstantEnum noConstant) {
      return new GoodEquals(a, b);
    }

    // instance method ignored

        header);
  }

  private static final class Reference<T> {
    private @Nullable T value;

    @Nullable T get() {
      return value;
    }

    void checkAndSet(@Nullable T expected, @Nullable T newValue) {
      if (value != expected) {
        throw new ConcurrentModificationException();
      }
      value = newValue;
    }

 *
 * @author Louis Wasserman
 */
@GwtIncompatible // not worth using in GWT for now
final class CompactLinkedHashSet<E extends @Nullable Object> extends CompactHashSet<E> {

  /** Creates an empty {@code CompactLinkedHashSet} instance. */
  public static <E extends @Nullable Object> CompactLinkedHashSet<E> create() {
    return new CompactLinkedHashSet<>();
  }

  /**

  @Override
  @ParametricNullness
  public <T extends @Nullable Object> T callWithTimeout(
      Callable<T> callable, long timeoutDuration, TimeUnit timeoutUnit) throws ExecutionException {
    checkNotNull(callable);
    checkNotNull(timeoutUnit);
    try {
      return callable.call();
    } catch (RuntimeException e) {
      throw new UncheckedExecutionException(e);

import java.util.concurrent.CountDownLatch;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import org.jspecify.annotations.NullUnmarked;
import org.jspecify.annotations.Nullable;

/**
 * Used to test listenable future implementations.
 *
 * @author Sven Mawson
 */
@NullUnmarked
public class ListenableFutureTester {

  private final ExecutorService exec;

     * @param <U> the type returned by the function
     */
    public interface ClosingFunction5<
        V1 extends @Nullable Object,
        V2 extends @Nullable Object,
        V3 extends @Nullable Object,
        V4 extends @Nullable Object,
        V5 extends @Nullable Object,
        U extends @Nullable Object> {
      /**
       * Applies this function to five inputs, or throws an exception if unable to do so.
       *