*
 * @author Charles Fry
 * @since 10.0
 */
@GwtIncompatible
public final class RemovalListeners {

  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
   */

   */
  SIZE {
    @Override
    boolean wasEvicted() {
      return true;
    }
  };

  /**
   * Returns {@code true} if there was an automatic removal due to eviction (the cause is neither
   * {@link #EXPLICIT} nor {@link #REPLACED}).
   */
  abstract boolean wasEvicted();

  }

  /** Returns the cause for which the entry was removed. */
  public RemovalCause getCause() {
    return cause;
  }

  /**
   * Returns {@code true} if there was an automatic removal due to eviction (the cause is neither
   * {@link RemovalCause#EXPLICIT} nor {@link RemovalCause#REPLACED}).
   */
  public boolean wasEvicted() {
    return cause.wasEvicted();
  }

/**
 * An object that can receive a notification when an entry is removed from a cache. The removal
 * resulting in notification could have occurred to an entry being manually removed or replaced, or
 * due to eviction resulting from timed expiration, exceeding a maximum size, or garbage collection.
 *
 * <p>An instance may be called concurrently by multiple threads to process different entries.

   */
  SIZE {
    @Override
    boolean wasEvicted() {
      return true;
    }
  };

  /**
   * Returns {@code true} if there was an automatic removal due to eviction (the cause is neither
   * {@link #EXPLICIT} nor {@link #REPLACED}).
   */
  abstract boolean wasEvicted();

/**
 * An object that can receive a notification when an entry is removed from a cache. The removal
 * resulting in notification could have occurred to an entry being manually removed or replaced, or
 * due to eviction resulting from timed expiration, exceeding a maximum size, or garbage collection.
 *
 * <p>An instance may be called concurrently by multiple threads to process different entries.

   * the map directly affect the cache.
   *
   * <p>Iterators from the returned map are at least <i>weakly consistent</i>: they are safe for
   * concurrent use, but if the cache is modified (including by eviction) after the iterator is
   * created, it is undefined which of the changes (if any) will be reflected in that iterator.
   */
  ConcurrentMap<K, V> asMap();

  /**

## Version 1.5.2

_2014-03-17_

 * Fix bug where deleting a file that was absent from the `HttpResponseCache`
   caused an IOException.
 * Fix bug in HTTP/2 where our HPACK decoder wasn't emitting entries in
   certain eviction scenarios, leading to dropped response headers.

## Version 1.5.1

_2014-03-11_

 * Fix 1.5.0 regression where connections should not have been recycled.

   * the map directly affect the cache.
   *
   * <p>Iterators from the returned map are at least <i>weakly consistent</i>: they are safe for
   * concurrent use, but if the cache is modified (including by eviction) after the iterator is
   * created, it is undefined which of the changes (if any) will be reflected in that iterator.
   *
   * <p><b>Warning to users of Java 8+:</b> do not call any of the new <i>default methods</i> that

 * (first-in-first-out). This data structure is logically equivalent to a circular buffer (i.e.,
 * cyclic buffer or ring buffer).
 *
 * <p>An evicting queue must be configured with a maximum size. Each time an element is added to a
 * full queue, the queue automatically removes its head element. This is different from conventional