*     Object} if any key is acceptable
 * @author Charles Fry
 * @since 10.0
 */
@GwtCompatible
@FunctionalInterface
public interface RemovalListener<K, V> {
  /**
   * Notifies the listener that a removal occurred at some point in the past.
   *
   * <p>This does not always signify that the key is now absent from the cache, as it may have
   * already been re-added.

 * @param <V> the most general type of values this listener can listen for; for example {@code
 *     Object} if any key is acceptable
 * @author Charles Fry
 * @since 10.0
 */
@GwtCompatible
public interface RemovalListener<K, V> {
  /**
   * Notifies the listener that a removal occurred at some point in the past.
   *
   * <p>This does not always signify that the key is now absent from the cache, as it may have
   * already been re-added.

  private RemovalListeners() {}

  /**
   * Returns a {@code RemovalListener} which processes all eviction notifications using {@code
   * executor}.
   *
   * @param listener the backing listener
   * @param executor the executor with which removal notifications are asynchronously executed
   */
  public static <K, V> RemovalListener<K, V> asynchronous(
      RemovalListener<K, V> listener, Executor executor) {
    checkNotNull(listener);

      boolean accessOrder,
      long maximumSize,
      StatsCounter statsCounter,
      @Nullable RemovalListener<? super K, ? super V> removalListener) {
    super(initialCapacity, loadFactor, accessOrder);
    this.maximumSize = maximumSize;
    this.statsCounter = statsCounter;
    this.removalListener = removalListener;
  }

  @Override
  protected boolean removeEldestEntry(Entry<K, Timestamped<V>> ignored) {

  private RemovalListeners() {}

  /**
   * Returns a {@code RemovalListener} which processes all eviction notifications using {@code
   * executor}.
   *
   * @param listener the backing listener
   * @param executor the executor with which removal notifications are asynchronously executed
   */
  public static <K, V> RemovalListener<K, V> asynchronous(
      RemovalListener<K, V> listener, Executor executor) {
    checkNotNull(listener);

import java.util.concurrent.atomic.AtomicInteger;
import org.jspecify.annotations.Nullable;

/**
 * Utility {@link RemovalListener} implementations intended for use in testing.
 *
 * @author mike nonemacher
 */
@GwtCompatible
final class TestingRemovalListeners {

  /** Returns a new no-op {@code RemovalListener}. */
  static <K, V> NullRemovalListener<K, V> nullRemovalListener() {
    return new NullRemovalListener<>();
  }

  }

  public void testComputeIfPresentRemove() {
    List<RemovalNotification<Integer, Integer>> notifications = new ArrayList<>();
    Cache<Integer, Integer> cache =
        CacheBuilder.newBuilder()
            .removalListener((RemovalNotification<Integer, Integer> n) -> notifications.add(n))
            .build();
    cache.put(1, 2);

    // explicitly remove the existing value
    cache.asMap().computeIfPresent(1, (key, value) -> null);