1/* 2 * Copyright (c) 2011, 2017, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 */ 23 24/* @test 25 * @bug 4268317 8132306 8175797 26 * @summary Test if Reference.enqueue() works properly with GC 27 * @run main ReferenceEnqueue 28 * @run main/othervm -Djdk.lang.ref.disableClearBeforeEnqueue=true ReferenceEnqueue 29 */ 30 31import java.lang.ref.*; 32import java.util.ArrayList; 33import java.util.List; 34 35public class ReferenceEnqueue { 36 37 public static void main(String args[]) throws Exception { 38 for (int i=0; i < 5; i++) { 39 new WeakRef().run(); 40 new ExplicitEnqueue().run(); 41 } 42 System.out.println("Test passed."); 43 } 44 45 static class WeakRef { 46 final ReferenceQueue<Object> queue = new ReferenceQueue<Object>(); 47 final Reference<Object> ref; 48 final int iterations = 1000; 49 50 WeakRef() { 51 this.ref = new WeakReference<Object>(new Object(), queue); 52 } 53 54 void run() throws InterruptedException { 55 System.gc(); 56 for (int i = 0; i < iterations; i++) { 57 System.gc(); 58 if (ref.isEnqueued()) { 59 break; 60 } 61 62 Thread.sleep(100); 63 } 64 65 if (ref.isEnqueued() == false) { 66 // GC have not enqueued refWeak for the timeout period 67 System.out.println("Reference not enqueued yet"); 68 return; 69 } 70 71 if (ref.enqueue() == true) { 72 // enqueue() should return false since 73 // ref is already enqueued by the GC 74 throw new RuntimeException("Error: enqueue() returned true;" 75 + " expected false"); 76 } 77 78 if (queue.poll() == null) { 79 // poll() should return ref enqueued by the GC 80 throw new RuntimeException("Error: poll() returned null;" 81 + " expected ref object"); 82 } 83 } 84 } 85 86 static class ExplicitEnqueue { 87 final ReferenceQueue<Object> queue = new ReferenceQueue<>(); 88 final List<Reference<Object>> refs = new ArrayList<>(); 89 final int iterations = 1000; 90 final boolean disableClearBeforeEnqueue = 91 Boolean.getBoolean("jdk.lang.ref.disableClearBeforeEnqueue"); 92 93 ExplicitEnqueue() { 94 this.refs.add(new SoftReference<>(new Object(), queue)); 95 this.refs.add(new WeakReference<>(new Object(), queue)); 96 // Can't test PhantomReference because get() always returns null. 97 } 98 99 void run() throws InterruptedException { 100 for (Reference<Object> ref : refs) { 101 if (ref.enqueue() == false) { 102 throw new RuntimeException("Error: enqueue failed"); 103 } 104 if (disableClearBeforeEnqueue && ref.get() == null) { 105 throw new RuntimeException("Error: clearing should be disabled"); 106 } 107 if (!disableClearBeforeEnqueue && ref.get() != null) { 108 throw new RuntimeException("Error: referent must be cleared"); 109 } 110 } 111 112 System.gc(); 113 for (int i = 0; refs.size() > 0 && i < iterations; i++) { 114 Reference<Object> ref = (Reference<Object>)queue.poll(); 115 if (ref == null) { 116 System.gc(); 117 Thread.sleep(100); 118 continue; 119 } 120 121 if (refs.remove(ref) == false) { 122 throw new RuntimeException("Error: unknown reference " + ref); 123 } 124 } 125 126 if (!refs.isEmpty()) { 127 throw new RuntimeException("Error: not all references are removed"); 128 } 129 } 130 } 131} 132