* null} if they were already garbage collected.
   *
   * @since 19.0
   */
  public static <K, V> RemovalNotification<K, V> create(
      @CheckForNull K key, @CheckForNull V value, RemovalCause cause) {
    return new RemovalNotification<>(key, value, cause);
  }

  private RemovalNotification(@CheckForNull K key, @CheckForNull V value, RemovalCause cause) {
    super(key, value);
    this.cause = checkNotNull(cause);
  }

   * null} if they were already garbage collected.
   *
   * @since 19.0
   */
  public static <K, V> RemovalNotification<K, V> create(
      @CheckForNull K key, @CheckForNull V value, RemovalCause cause) {
    return new RemovalNotification<>(key, value, cause);
  }

  private RemovalNotification(@CheckForNull K key, @CheckForNull V value, RemovalCause cause) {
    super(key, value);
    this.cause = checkNotNull(cause);
  }

   * 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);

  }

  /** {@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);
    }
  }

  /**

import junit.framework.TestCase;

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

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

package org.gradle.api.internal.tasks.scala;


import com.google.common.cache.Cache;
import com.google.common.cache.CacheBuilder;
import com.google.common.cache.RemovalListener;
import com.google.common.cache.RemovalNotification;

import java.util.concurrent.Callable;

/**
 * Simple guava-based classloader cache. Usually used with a very small size (< 10),
 * as classloaders are strongly referenced.
 *

   * 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);

 */

package org.gradle.cache.internal;

import com.google.common.cache.Cache;
import com.google.common.cache.RemovalCause;
import com.google.common.cache.RemovalListener;
import com.google.common.cache.RemovalNotification;
import org.slf4j.Logger;

import java.util.concurrent.atomic.AtomicInteger;

class LoggingEvictionListener implements RemovalListener<Object, Object> {

            .maximumSize(0)
            .removalListener(listener)
            .build(constantLoader(computed));

    Object key = new Object();
    assertSame(computed, cache.getUnchecked(key));
    RemovalNotification<Object, Object> notification = listener.remove();
    assertSame(key, notification.getKey());
    assertSame(computed, notification.getValue());
    assertSame(RemovalCause.SIZE, notification.getCause());

            .maximumSize(0)
            .removalListener(listener)
            .build(constantLoader(computed));

    Object key = new Object();
    assertSame(computed, cache.getUnchecked(key));
    RemovalNotification<Object, Object> notification = listener.remove();
    assertSame(key, notification.getKey());
    assertSame(computed, notification.getValue());
    assertSame(RemovalCause.SIZE, notification.getCause());