1 /*
2  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
3  *
4  * This code is free software; you can redistribute it and/or modify it
5  * under the terms of the GNU General Public License version 2 only, as
6  * published by the Free Software Foundation.
7  *
8  * This code is distributed in the hope that it will be useful, but WITHOUT
9  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
10  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
11  * version 2 for more details (a copy is included in the LICENSE file that
12  * accompanied this code).
13  *
14  * You should have received a copy of the GNU General Public License version
15  * 2 along with this work; if not, write to the Free Software Foundation,
16  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
17  *
18  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
19  * or visit www.oracle.com if you need additional information or have any
20  * questions.
21  */
22 
23 /*
24  * This file is available under and governed by the GNU General Public
25  * License version 2 only, as published by the Free Software Foundation.
26  * However, the following notice accompanied the original version of this
27  * file:
28  *
29  * Written by Doug Lea with assistance from members of JCP JSR-166
30  * Expert Group and released to the public domain, as explained at
31  * http://creativecommons.org/publicdomain/zero/1.0/
32  * Other contributors include Andrew Wright, Jeffrey Hayes,
33  * Pat Fisher, Mike Judd.
34  */
35 
36 import static java.util.concurrent.TimeUnit.MILLISECONDS;
37 
38 import java.util.concurrent.CountDownLatch;
39 import java.util.concurrent.Exchanger;
40 import java.util.concurrent.TimeoutException;
41 
42 import junit.framework.Test;
43 import junit.framework.TestSuite;
44 
45 public class ExchangerTest extends JSR166TestCase {
46 
main(String[] args)47     public static void main(String[] args) {
48         main(suite(), args);
49     }
suite()50     public static Test suite() {
51         return new TestSuite(ExchangerTest.class);
52     }
53 
54     /**
55      * exchange exchanges objects across two threads
56      */
testExchange()57     public void testExchange() {
58         final Exchanger<Item> e = new Exchanger<>();
59         Thread t1 = newStartedThread(new CheckedRunnable() {
60             public void realRun() throws InterruptedException {
61                 assertSame(one, e.exchange(two));
62                 assertSame(two, e.exchange(one));
63             }});
64         Thread t2 = newStartedThread(new CheckedRunnable() {
65             public void realRun() throws InterruptedException {
66                 assertSame(two, e.exchange(one));
67                 assertSame(one, e.exchange(two));
68             }});
69 
70         awaitTermination(t1);
71         awaitTermination(t2);
72     }
73 
74     /**
75      * timed exchange exchanges objects across two threads
76      */
testTimedExchange()77     public void testTimedExchange() {
78         final Exchanger<Item> e = new Exchanger<>();
79         Thread t1 = newStartedThread(new CheckedRunnable() {
80             public void realRun() throws Exception {
81                 assertSame(one, e.exchange(two, LONG_DELAY_MS, MILLISECONDS));
82                 assertSame(two, e.exchange(one, LONG_DELAY_MS, MILLISECONDS));
83             }});
84         Thread t2 = newStartedThread(new CheckedRunnable() {
85             public void realRun() throws Exception {
86                 assertSame(two, e.exchange(one, LONG_DELAY_MS, MILLISECONDS));
87                 assertSame(one, e.exchange(two, LONG_DELAY_MS, MILLISECONDS));
88             }});
89 
90         awaitTermination(t1);
91         awaitTermination(t2);
92     }
93 
94     /**
95      * interrupt during wait for exchange throws InterruptedException
96      */
testExchange_InterruptedException()97     public void testExchange_InterruptedException() {
98         final Exchanger<Item> e = new Exchanger<>();
99         final CountDownLatch threadStarted = new CountDownLatch(1);
100         Thread t = newStartedThread(new CheckedInterruptedRunnable() {
101             public void realRun() throws InterruptedException {
102                 threadStarted.countDown();
103                 e.exchange(one);
104             }});
105 
106         await(threadStarted);
107         t.interrupt();
108         awaitTermination(t);
109     }
110 
111     /**
112      * interrupt during wait for timed exchange throws InterruptedException
113      */
testTimedExchange_InterruptedException()114     public void testTimedExchange_InterruptedException() {
115         final Exchanger<Item> e = new Exchanger<>();
116         final CountDownLatch threadStarted = new CountDownLatch(1);
117         Thread t = newStartedThread(new CheckedInterruptedRunnable() {
118             public void realRun() throws Exception {
119                 threadStarted.countDown();
120                 e.exchange(null, LONG_DELAY_MS, MILLISECONDS);
121             }});
122 
123         await(threadStarted);
124         t.interrupt();
125         awaitTermination(t);
126     }
127 
128     /**
129      * timeout during wait for timed exchange throws TimeoutException
130      */
testExchange_TimeoutException()131     public void testExchange_TimeoutException() {
132         final Exchanger<Item> e = new Exchanger<>();
133         Thread t = newStartedThread(new CheckedRunnable() {
134             public void realRun() throws Exception {
135                 long startTime = System.nanoTime();
136                 try {
137                     e.exchange(null, timeoutMillis(), MILLISECONDS);
138                     shouldThrow();
139                 } catch (TimeoutException success) {}
140                 assertTrue(millisElapsedSince(startTime) >= timeoutMillis());
141             }});
142 
143         awaitTermination(t);
144     }
145 
146     /**
147      * If one exchanging thread is interrupted, another succeeds.
148      */
testReplacementAfterExchange()149     public void testReplacementAfterExchange() {
150         final Exchanger<Item> e = new Exchanger<>();
151         final CountDownLatch exchanged = new CountDownLatch(2);
152         final CountDownLatch interrupted = new CountDownLatch(1);
153         Thread t1 = newStartedThread(new CheckedInterruptedRunnable() {
154             public void realRun() throws InterruptedException {
155                 assertSame(two, e.exchange(one));
156                 exchanged.countDown();
157                 e.exchange(two);
158             }});
159         Thread t2 = newStartedThread(new CheckedRunnable() {
160             public void realRun() throws InterruptedException {
161                 assertSame(one, e.exchange(two));
162                 exchanged.countDown();
163                 await(interrupted);
164                 assertSame(three, e.exchange(one));
165             }});
166         Thread t3 = newStartedThread(new CheckedRunnable() {
167             public void realRun() throws InterruptedException {
168                 await(interrupted);
169                 assertSame(one, e.exchange(three));
170             }});
171 
172         await(exchanged);
173         t1.interrupt();
174         awaitTermination(t1);
175         interrupted.countDown();
176         awaitTermination(t2);
177         awaitTermination(t3);
178     }
179 
180 }
181