}

  public void testComputeIfPresentRemove() {
    List<RemovalNotification<Integer, Integer>> notifications = new ArrayList<>();
    Cache<Integer, Integer> cache =
        CacheBuilder.newBuilder()
            .removalListener(
                new RemovalListener<Integer, Integer>() {
                  @Override
                  public void onRemoval(RemovalNotification<Integer, Integer> notification) {

  }

  /** {@link RemovalListener} that adds all {@link RemovalNotification} objects to a queue. */
  @GwtIncompatible // ConcurrentLinkedQueue
  static class QueuingRemovalListener<K, V> extends ConcurrentLinkedQueue<RemovalNotification<K, V>>
      implements RemovalListener<K, V> {

    @Override
    public void onRemoval(RemovalNotification<K, V> notification) {
      add(notification);
    }
  }

  /**

/**
 * Unit tests of {@link RemovalNotification}.
 *
 * @author Ben Yu
 */
@NullUnmarked
public class RemovalNotificationTest extends TestCase {

  public void testEquals() {
    new EqualsTester()
        .addEqualityGroup(
            RemovalNotification.create("one", 1, RemovalCause.EXPLICIT),
            RemovalNotification.create("one", 1, RemovalCause.REPLACED))

/**
 * Unit tests of {@link RemovalNotification}.
 *
 * @author Ben Yu
 */
@NullUnmarked
public class RemovalNotificationTest extends TestCase {

  public void testEquals() {
    new EqualsTester()
        .addEqualityGroup(
            RemovalNotification.create("one", 1, RemovalCause.EXPLICIT),
            RemovalNotification.create("one", 1, RemovalCause.REPLACED))

  }

  /** {@link RemovalListener} that adds all {@link RemovalNotification} objects to a queue. */
  @GwtIncompatible // ConcurrentLinkedQueue
  static class QueuingRemovalListener<K, V> extends ConcurrentLinkedQueue<RemovalNotification<K, V>>
      implements RemovalListener<K, V> {

    @Override
    public void onRemoval(RemovalNotification<K, V> notification) {
      add(notification);
    }
  }

  /**

            .removalListener(listener)
            .build(constantLoader(computed));

    Object key = new Object();
    assertThat(cache.getUnchecked(key)).isSameInstanceAs(computed);
    RemovalNotification<Object, Object> notification = listener.remove();
    assertThat(notification.getKey()).isSameInstanceAs(key);
    assertThat(notification.getValue()).isSameInstanceAs(computed);

            .removalListener(listener)
            .build(constantLoader(computed));

    Object key = new Object();
    assertThat(cache.getUnchecked(key)).isSameInstanceAs(computed);
    RemovalNotification<Object, Object> notification = listener.remove();
    assertThat(notification.getKey()).isSameInstanceAs(key);
    assertThat(notification.getValue()).isSameInstanceAs(computed);

   * already been re-added.
   */
  // Technically should accept RemovalNotification<? extends K, ? extends V>, but because
  // RemovalNotification is guaranteed covariant, let's make users' lives simpler.
  void onRemoval(RemovalNotification<K, V> notification);

   */
  public static <K, V> RemovalListener<K, V> asynchronous(
      RemovalListener<K, V> listener, Executor executor) {
    checkNotNull(listener);
    checkNotNull(executor);
    return (RemovalNotification<K, V> notification) ->
        executor.execute(() -> listener.onRemoval(notification));
  }

    // contain the computed value (b -> b), since the clear() happened before the computation
    // completed.
    assertThat(listener).hasSize(1);
    RemovalNotification<String, String> notification = listener.remove();
    assertThat(notification.getKey()).isEqualTo("a");
    assertThat(notification.getValue()).isEqualTo("a");
    assertThat(cache.size()).isEqualTo(1);