1 /*
2 * Copyright (c) 2011, 2013, 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.
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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 /**
25 @test
26 @summary Some tests for the Lock spec
27 @summary com.apple.junit.java.lang.LanguageSpec;
28 @run main LockTest
29 */
30
31 import junit.framework.*;
32
33 import java.util.Timer;
34 import java.util.TimerTask;
35
36 //Lock class representation of Lock, with flag to indicate whether locked or not, and with
37 //count of number of times lock acquired.
38 class Lock {
39 static int numLocks = 0;
40 static boolean isLocked = false;
41
42 //Acquires lock and increments numLock
43 public static synchronized void acquire() throws Exception {
44 if ( numLocks < 0) {
45 throw new Exception("Locking logic error");
46 }
47 numLocks++;
48 isLocked = true;
49 }
50
51 //Releases current lock, if all locks released, Lock is unlocked
52 public static synchronized void release() throws Exception {
53 if ( numLocks < 1) {
54 throw new Exception("Locking logic error");
55 }
56 numLocks--;
57
58 if(numLocks == 0)
59 isLocked = false;
60 }
61 }
62
63
64 public class LockTest extends TestCase {
65 Thread t1;
66 Thread t2;
67 Lock l1;
68 TimerTask stopper;
69 static volatile boolean done;
70 Timer timer;
71
72 class Stopper extends TimerTask{
73 public void run(){
74 done = true;
75 }
76 }
77
78 //Sets up new threads t1 and t2.
79 public void setUp(){
80 l1 = new Lock();
81 done = false;
82 }
83
84
85 //Create two threads. One uses synchronized to aqcuire multiple locks on the instance l1 of Lock
86 //The other thread attempts to acquire a lock on l1 while it is already locked by the first thread
87 //If the second thread manages to acquire a lock on l1 while already locked by the first thread,
88 //the test fails. Also tests number of locks acquired.
89 //Tests JVM spec as specified in 8.5 and 8.6
90
91 Exception cachedException;
92
93 public void testLock() throws Exception {
94 timer = new Timer();
95 t1 = new Thread( new Runnable() {
96 public void run() {
97 try{
98 while (!done) {
99 synchronized(l1) {
100 assertFalse(Lock.isLocked);
101 Lock.acquire();
102 assertEquals(Lock.numLocks, 1);
103 Thread.sleep(10);
104 synchronized(l1) {
105 Lock.acquire();
106 assertEquals(Lock.numLocks, 2);
107 Thread.sleep(10);
108 synchronized(l1) {
109 Lock.acquire();
110 assertEquals(Lock.numLocks, 3);
111 Thread.sleep(10);
112 Lock.release();
113 assertEquals(Lock.numLocks, 2);
114 }
115 Thread.sleep(10);
116 Lock.release();
117 assertEquals(Lock.numLocks, 1);
118 }
119 Thread.sleep(10);
120 Lock.release();
121 assertEquals(Lock.numLocks, 0);
122 }
123 }
124 } catch (Exception e) {
125 cachedException = e;
126 }
127 }
128 });
129
130 t2 = new Thread ( new Runnable() {
131 public void run() {
132 try {
133 while(!done) {
134 synchronized(l1){
135 assertFalse(Lock.isLocked);
136 Lock.acquire();
137 assertEquals(Lock.numLocks, 1);
138 Lock.release();
139 assertEquals(Lock.numLocks, 0);
140 }
141 }
142 } catch (Exception e) {
143 cachedException = e;
144 }
145 }
146 });
147
148 try {
149 timer.schedule(new Stopper(), 500);
150 t1.start();
151 t2.start();
152 t1.join();
153 t2.join();
154
155 if (cachedException != null) {
156 throw cachedException;
157 }
158 }
159
160 finally {
161 timer.cancel();
162 }
163
164 }
165
166 public static Test suite() {
167 return new TestSuite( LockTest.class);
168 }
169
170 public static void main (String[] args) throws RuntimeException {
171 TestResult tr = junit.textui.TestRunner.run(suite());
172 if((tr.errorCount() != 0) || (tr.failureCount() != 0)) {
173 throw new RuntimeException("### Unexpected JUnit errors or failures.");
174 }
175 }
176 }
177