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 17 package com.google.common.base; 18 19 import java.lang.ref.ReferenceQueue; 20 import 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 */ 30 public 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 */ FinalizableWeakReference(T referent, FinalizableReferenceQueue queue)38 protected FinalizableWeakReference(T referent, FinalizableReferenceQueue queue) { 39 super(referent, queue.queue); 40 queue.cleanUp(); 41 } 42 } 43