import org.jspecify.annotations.Nullable;

/** Implementations of {@code Futures.transform*}. */
@GwtCompatible
// Whenever both tests are cheap and functional, it's faster to use &, | instead of &&, ||
@SuppressWarnings("ShortCircuitBoolean")
abstract class AbstractTransformFuture<
        I extends @Nullable Object, O extends @Nullable Object, F, T extends @Nullable Object>

  static final class ListFuture<V extends @Nullable Object>
      extends CollectionFuture<V, List<@Nullable V>> {
    ListFuture(
        ImmutableCollection<? extends ListenableFuture<? extends V>> futures,
        boolean allMustSucceed) {
      super(futures, allMustSucceed);
      init();
    }

    @Override
    public List<@Nullable V> combine(List<@Nullable Present<V>> values) {

            DefaultToolchainsBuilderRequest(
                    @Nonnull ProtoSession session,
                    @Nullable RequestTrace trace,
                    @Nullable Source installationToolchainsSource,
                    @Nullable Source userToolchainsSource) {
                super(session, trace);
                this.installationToolchainsSource = installationToolchainsSource;

   */
  public static <T extends @Nullable Object> Iterable<List<@Nullable T>> paddedPartition(
      Iterable<T> iterable, int size) {
    checkNotNull(iterable);
    checkArgument(size > 0);
    return new FluentIterable<List<@Nullable T>>() {
      @Override
      public Iterator<List<@Nullable T>> iterator() {
        return Iterators.paddedPartition(iterable.iterator(), size);

public final class CollectorTester<
    T extends @Nullable Object, A extends @Nullable Object, R extends @Nullable Object> {
  /**
   * Creates a {@code CollectorTester} for the specified {@code Collector}. The result of the {@code
   * Collector} will be compared to the expected value using {@link Object#equals}.
   */
  public static <T extends @Nullable Object, A extends @Nullable Object, R extends @Nullable Object>

   * there's no way to assign a {@code @Nullable T} to a field {@code T foo;} and instruct the
   * analysis that that means "plain {@code T}" rather than the inferred type {@code @Nullable T}.
   * (And even if annotations on local variables were permitted as an optional hint, no annotation
   * would be the right tool for the job here: {@code @Nullable} is the annotation that we're trying

   * there's no way to assign a {@code @Nullable T} to a field {@code T foo;} and instruct the
   * analysis that that means "plain {@code T}" rather than the inferred type {@code @Nullable T}.
   * (And even if annotations on local variables were permitted as an optional hint, no annotation
   * would be the right tool for the job here: {@code @Nullable} is the annotation that we're trying

   */
  public static MultimapBuilderWithKeys<@Nullable Object> linkedHashKeys(int expectedKeys) {
    checkNonnegative(expectedKeys, "expectedKeys");
    return new MultimapBuilderWithKeys<@Nullable Object>() {
      @Override
      <K extends @Nullable Object, V extends @Nullable Object> Map<K, Collection<V>> createMap() {
        return Platform.newLinkedHashMapWithExpectedSize(expectedKeys);

  }

  private static Iterable<@Nullable Object> iterable(
      @Nullable Object first, @Nullable Object second, @Nullable Object[] rest) {
    checkNotNull(rest);
    return new AbstractList<@Nullable Object>() {
      @Override
      public int size() {
        return rest.length + 2;
      }

      @Override
      public @Nullable Object get(int index) {
        switch (index) {

import org.jspecify.annotations.NullMarked;
import org.jspecify.annotations.Nullable;

/**
 * Tests for {@link Functions}.
 *
 * @author Mike Bostock
 * @author Vlad Patryshev
 */
@GwtCompatible
@NullMarked
public class FunctionsTest extends TestCase {

  public void testIdentity_same() {
    Function<@Nullable String, @Nullable String> identity = Functions.identity();
    assertThat(identity.apply(null)).isNull();