return i;
          }
        };

    List<Future<Integer>> futures = executor.invokeAll(Collections.nCopies(10, incrementTask));

    for (int i = 0; i < 10; i++) {
      Future<Integer> future = futures.get(i);
      assertTrue("Task should have been run before being returned", future.isDone());
      assertEquals(i, future.get().intValue());
    }

 */

package com.google.common.util.concurrent;

import static com.google.common.truth.Truth.assertThat;
import static com.google.common.util.concurrent.Callables.returning;
import static com.google.common.util.concurrent.Futures.getDone;
import static com.google.common.util.concurrent.ReflectionFreeAssertThrows.assertThrows;
import static com.google.common.util.concurrent.TestPlatform.verifyThreadWasNotInterrupted;

   * Future} instances to be upgraded to {@code ListenableFuture} after the fact.
   */
  public static <V extends @Nullable Object> ListenableFuture<V> listenInPoolThread(
      Future<V> future) {
    if (future instanceof ListenableFuture) {
      return (ListenableFuture<V>) future;
    }
    return new ListenableFutureAdapter<>(future);
  }

  /**

import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.ScheduledFuture;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import org.jspecify.annotations.Nullable;

/**
 * Implementation of {@code Futures#withTimeout}.
 *

    /**
     * Contains the most recently submitted {@code Future}, which may be cancelled or updated,
     * always under a lock.
     */
    private static final class SupplantableFuture implements Cancellable {
      private final ReentrantLock lock;

      @GuardedBy("lock")
      private Future<@Nullable Void> currentFuture;

      SupplantableFuture(ReentrantLock lock, Future<@Nullable Void> currentFuture) {
        this.lock = lock;

    /**
     * Contains the most recently submitted {@code Future}, which may be cancelled or updated,
     * always under a lock.
     */
    private static final class SupplantableFuture implements Cancellable {
      private final ReentrantLock lock;

      @GuardedBy("lock")
      private Future<@Nullable Void> currentFuture;

      SupplantableFuture(ReentrantLock lock, Future<@Nullable Void> currentFuture) {
        this.lock = lock;

        if (future.listenersField == expect) {
          future.listenersField = update;
          return true;
        }
        return false;
      }
    }

    @Override
    @Nullable Listener gasListeners(AbstractFutureState<?> future, Listener update) {
      synchronized (future) {
        Listener old = future.listenersField;
        if (old != update) {
          future.listenersField = update;

        if (future.listenersField == expect) {
          future.listenersField = update;
          return true;
        }
        return false;
      }
    }

    @Override
    @Nullable Listener gasListeners(AbstractFutureState<?> future, Listener update) {
      synchronized (future) {
        Listener old = future.listenersField;
        if (old != update) {
          future.listenersField = update;

import static com.google.common.cache.CacheBuilder.UNSET_INT;
import static com.google.common.util.concurrent.Futures.immediateFailedFuture;
import static com.google.common.util.concurrent.Futures.immediateFuture;
import static com.google.common.util.concurrent.Futures.transform;
import static com.google.common.util.concurrent.MoreExecutors.directExecutor;

import static com.google.common.truth.Truth.assertThat;
import static com.google.common.truth.Truth.assertWithMessage;
import static com.google.common.util.concurrent.Futures.immediateFailedFuture;
import static com.google.common.util.concurrent.Futures.immediateFuture;
import static java.util.Arrays.asList;
import static java.util.concurrent.TimeUnit.MILLISECONDS;
import static java.util.concurrent.TimeUnit.SECONDS;