import com.google.common.annotations.J2ktIncompatible;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import java.util.concurrent.FutureTask;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import org.checkerframework.checker.nullness.qual.Nullable;

/**

    assertFalse(future.isCancelled());

    ExecutorService executor = Executors.newSingleThreadExecutor();

    try {
      Future<Boolean> getResult = executor.submit(() -> future.get());

      // Release the future value.
      latch.countDown();

      assertTrue(getResult.get(10, SECONDS));
    } finally {
      executor.shutdownNow();
    }

    assertTrue(future.isDone());

import com.google.common.annotations.GwtCompatible;
import com.google.common.util.concurrent.TestExceptions.SomeError;
import java.util.concurrent.CancellationException;
import java.util.concurrent.Executor;
import junit.framework.TestCase;
import org.checkerframework.checker.nullness.qual.Nullable;

/**
 * Test for {@link FutureCallback}.
 *
 * @author Anthony Zana
 */
@GwtCompatible

    graph.putEdgeValue(5, 6, "C");

    int threadCount = 20;
    ExecutorService executor = newFixedThreadPool(threadCount);
    final CyclicBarrier barrier = new CyclicBarrier(threadCount);
    ImmutableList.Builder<Future<?>> futures = ImmutableList.builder();
    for (int i = 0; i < threadCount; i++) {
      futures.add(
          executor.submit(
              new Callable<@Nullable Void>() {
                @Override

import java.util.concurrent.ConcurrentMap;
import java.util.concurrent.ConcurrentNavigableMap;
import java.util.concurrent.ConcurrentSkipListMap;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executor;
import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.ScheduledThreadPoolExecutor;
import java.util.concurrent.ThreadFactory;
import java.util.concurrent.ThreadPoolExecutor;

    override fun <T> decorate(queue: BlockingQueue<T>) = queue

    override fun execute(
      taskRunner: TaskRunner,
      runnable: Runnable,
    ) {
      executor.execute(runnable)
    }

    fun shutdown() {
      executor.shutdown()
    }
  }

  companion object {
    val logger: Logger = Logger.getLogger(TaskRunner::class.java.name)

    @JvmField

{* ../../docs_src/background_tasks/tutorial001.py hl[1,13] *}

**FastAPI** créera l'objet de type `BackgroundTasks` pour vous et le passera comme paramètre.

## Créer une fonction de tâche

Une fonction à exécuter comme tâche d'arrière-plan est juste une fonction standard qui peut recevoir des paramètres.

Elle peut être une fonction asynchrone (`async def`) ou une fonction normale (`def`), **FastAPI** saura la gérer correctement.

  @Override
  public final Throwable failureCause() {
    return snapshot.failureCause();
  }

  /** @since 13.0 */
  @Override
  public final void addListener(Listener listener, Executor executor) {
    listeners.addListener(listener, executor);
  }

  @Override
  public String toString() {
    return getClass().getSimpleName() + " [" + state() + "]";
  }

  /**

import static java.util.concurrent.TimeUnit.SECONDS;

import com.google.common.testing.NullPointerTester;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.Executor;
import java.util.concurrent.Executors;
import java.util.concurrent.atomic.AtomicInteger;
import junit.framework.TestCase;

/**
 * Unit tests for {@link ExecutionList}.
 *
 * @author Nishant Thakkar

 * make sense for different situations.
 *
 * <p><b>Note:</b> The dispatcher is orthogonal to the subscriber's {@code Executor}. The dispatcher
 * controls the order in which events are dispatched, while the executor controls how (i.e. on which
 * thread) the subscriber is actually called when an event is dispatched to it.
 *
 * @author Colin Decker
 */
@ElementTypesAreNonnullByDefault