1/*
2 * Copyright (C) 2007 The Guava Authors
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package com.google.common.base;
18
19import java.lang.ref.ReferenceQueue;
20import java.lang.ref.WeakReference;
21
22/**
23 * Weak reference with a {@code finalizeReferent()} method which a background thread invokes after
24 * the garbage collector reclaims the referent. This is a simpler alternative to using a {@link
25 * ReferenceQueue}.
26 *
27 * @author Bob Lee
28 * @since 2.0 (imported from Google Collections Library)
29 */
30public abstract class FinalizableWeakReference<T> extends WeakReference<T>
31    implements FinalizableReference {
32  /**
33   * Constructs a new finalizable weak reference.
34   *
35   * @param referent to weakly reference
36   * @param queue that should finalize the referent
37   */
38  protected FinalizableWeakReference(T referent, FinalizableReferenceQueue queue) {
39    super(referent, queue.queue);
40    queue.cleanUp();
41  }
42}
43