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1 /*
2  * Copyright (C) 2010 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.util.concurrent;
18 
19 import com.google.common.testing.NullPointerTester;
20 import com.google.common.testing.TearDownStack;
21 
22 import junit.framework.TestCase;
23 
24 import java.util.Random;
25 import java.util.concurrent.TimeUnit;
26 
27 /**
28  * Tests for {@link Monitor}, either interruptible or uninterruptible.
29  *
30  * @author Justin T. Sampson
31  */
32 
33 public abstract class MonitorTestCase extends TestCase {
34 
35   public class TestGuard extends Monitor.Guard {
36     private volatile boolean satisfied;
37 
TestGuard(boolean satisfied)38     public TestGuard(boolean satisfied) {
39       super(MonitorTestCase.this.monitor);
40       this.satisfied = satisfied;
41     }
42 
isSatisfied()43     @Override public boolean isSatisfied() {
44       return this.satisfied;
45     }
46 
setSatisfied(boolean satisfied)47     public void setSatisfied(boolean satisfied) {
48       this.satisfied = satisfied;
49     }
50   }
51 
52   private final boolean interruptible;
53   private Monitor monitor;
54   private final TearDownStack tearDownStack = new TearDownStack(true);
55   private TestThread<Monitor> thread1;
56   private TestThread<Monitor> thread2;
57 
MonitorTestCase(boolean interruptible)58   protected MonitorTestCase(boolean interruptible) {
59     this.interruptible = interruptible;
60   }
61 
setUp()62   @Override protected final void setUp() throws Exception {
63     boolean fair = new Random().nextBoolean();
64     monitor = new Monitor(fair);
65     tearDownStack.addTearDown(thread1 = new TestThread<Monitor>(monitor, "TestThread #1"));
66     tearDownStack.addTearDown(thread2 = new TestThread<Monitor>(monitor, "TestThread #2"));
67   }
68 
tearDown()69   @Override protected final void tearDown() {
70     tearDownStack.runTearDown();
71   }
72 
enter()73   private String enter() {
74     return interruptible ? "enterInterruptibly" : "enter";
75   }
76 
tryEnter()77   private String tryEnter() {
78     return "tryEnter";
79   }
80 
enterIf()81   private String enterIf() {
82     return interruptible ? "enterIfInterruptibly" : "enterIf";
83   }
84 
tryEnterIf()85   private String tryEnterIf() {
86     return "tryEnterIf";
87   }
88 
enterWhen()89   private String enterWhen() {
90     return interruptible ? "enterWhen" : "enterWhenUninterruptibly";
91   }
92 
waitFor()93   private String waitFor() {
94     return interruptible ? "waitFor" : "waitForUninterruptibly";
95   }
96 
leave()97   private String leave() {
98     return "leave";
99   }
100 
testMutualExclusion()101   public final void testMutualExclusion() throws Exception {
102     thread1.callAndAssertReturns(enter());
103     thread2.callAndAssertBlocks(enter());
104     thread1.callAndAssertReturns(leave());
105     thread2.assertPriorCallReturns(enter());
106   }
107 
testTryEnter()108   public final void testTryEnter() throws Exception {
109     thread1.callAndAssertReturns(true, tryEnter());
110     thread2.callAndAssertReturns(false, tryEnter());
111     thread1.callAndAssertReturns(true, tryEnter());
112     thread2.callAndAssertReturns(false, tryEnter());
113     thread1.callAndAssertReturns(leave());
114     thread2.callAndAssertReturns(false, tryEnter());
115     thread1.callAndAssertReturns(leave());
116     thread2.callAndAssertReturns(true, tryEnter());
117   }
118 
testSystemStateMethods()119   public final void testSystemStateMethods() throws Exception {
120     checkSystemStateMethods(0);
121     thread1.callAndAssertReturns(enter());
122     checkSystemStateMethods(1);
123     thread1.callAndAssertReturns(enter());
124     checkSystemStateMethods(2);
125     thread1.callAndAssertReturns(leave());
126     checkSystemStateMethods(1);
127     thread1.callAndAssertReturns(leave());
128     checkSystemStateMethods(0);
129   }
130 
checkSystemStateMethods(int enterCount)131   private void checkSystemStateMethods(int enterCount) throws Exception {
132     thread1.callAndAssertReturns(enterCount != 0, "isOccupied");
133     thread1.callAndAssertReturns(enterCount != 0, "isOccupiedByCurrentThread");
134     thread1.callAndAssertReturns(enterCount, "getOccupiedDepth");
135 
136     thread2.callAndAssertReturns(enterCount != 0, "isOccupied");
137     thread2.callAndAssertReturns(false, "isOccupiedByCurrentThread");
138     thread2.callAndAssertReturns(0, "getOccupiedDepth");
139   }
140 
testEnterWhen_initiallyTrue()141   public final void testEnterWhen_initiallyTrue() throws Exception {
142     TestGuard guard = new TestGuard(true);
143     thread1.callAndAssertReturns(enterWhen(), guard);
144   }
145 
testEnterWhen_initiallyFalse()146   public final void testEnterWhen_initiallyFalse() throws Exception {
147     TestGuard guard = new TestGuard(false);
148     thread1.callAndAssertWaits(enterWhen(), guard);
149     monitor.enter();
150     guard.setSatisfied(true);
151     monitor.leave();
152     thread1.assertPriorCallReturns(enterWhen());
153   }
154 
testEnterWhen_alreadyOccupied()155   public final void testEnterWhen_alreadyOccupied() throws Exception {
156     TestGuard guard = new TestGuard(true);
157     thread2.callAndAssertReturns(enter());
158     thread1.callAndAssertBlocks(enterWhen(), guard);
159     thread2.callAndAssertReturns(leave());
160     thread1.assertPriorCallReturns(enterWhen());
161   }
162 
testEnterIf_initiallyTrue()163   public final void testEnterIf_initiallyTrue() throws Exception {
164     TestGuard guard = new TestGuard(true);
165     thread1.callAndAssertReturns(true, enterIf(), guard);
166     thread2.callAndAssertBlocks(enter());
167   }
168 
testEnterIf_initiallyFalse()169   public final void testEnterIf_initiallyFalse() throws Exception {
170     TestGuard guard = new TestGuard(false);
171     thread1.callAndAssertReturns(false, enterIf(), guard);
172     thread2.callAndAssertReturns(enter());
173   }
174 
testEnterIf_alreadyOccupied()175   public final void testEnterIf_alreadyOccupied() throws Exception {
176     TestGuard guard = new TestGuard(true);
177     thread2.callAndAssertReturns(enter());
178     thread1.callAndAssertBlocks(enterIf(), guard);
179     thread2.callAndAssertReturns(leave());
180     thread1.assertPriorCallReturns(true, enterIf());
181   }
182 
testTryEnterIf_initiallyTrue()183   public final void testTryEnterIf_initiallyTrue() throws Exception {
184     TestGuard guard = new TestGuard(true);
185     thread1.callAndAssertReturns(true, tryEnterIf(), guard);
186     thread2.callAndAssertBlocks(enter());
187   }
188 
testTryEnterIf_initiallyFalse()189   public final void testTryEnterIf_initiallyFalse() throws Exception {
190     TestGuard guard = new TestGuard(false);
191     thread1.callAndAssertReturns(false, tryEnterIf(), guard);
192     thread2.callAndAssertReturns(enter());
193   }
194 
testTryEnterIf_alreadyOccupied()195   public final void testTryEnterIf_alreadyOccupied() throws Exception {
196     TestGuard guard = new TestGuard(true);
197     thread2.callAndAssertReturns(enter());
198     thread1.callAndAssertReturns(false, tryEnterIf(), guard);
199   }
200 
testWaitFor_initiallyTrue()201   public final void testWaitFor_initiallyTrue() throws Exception {
202     TestGuard guard = new TestGuard(true);
203     thread1.callAndAssertReturns(enter());
204     thread1.callAndAssertReturns(waitFor(), guard);
205   }
206 
testWaitFor_initiallyFalse()207   public final void testWaitFor_initiallyFalse() throws Exception {
208     TestGuard guard = new TestGuard(false);
209     thread1.callAndAssertReturns(enter());
210     thread1.callAndAssertWaits(waitFor(), guard);
211     monitor.enter();
212     guard.setSatisfied(true);
213     monitor.leave();
214     thread1.assertPriorCallReturns(waitFor());
215   }
216 
testWaitFor_withoutEnter()217   public final void testWaitFor_withoutEnter() throws Exception {
218     TestGuard guard = new TestGuard(true);
219     thread1.callAndAssertThrows(IllegalMonitorStateException.class, waitFor(), guard);
220   }
221 
testNulls()222   public void testNulls() {
223     monitor.enter();  // Inhibit IllegalMonitorStateException
224     new NullPointerTester()
225         .setDefault(TimeUnit.class, TimeUnit.SECONDS)
226         .setDefault(Monitor.Guard.class, new TestGuard(true))
227         .testAllPublicInstanceMethods(monitor);
228   }
229 
230   // TODO: Test enter(long, TimeUnit).
231   // TODO: Test enterWhen(Guard, long, TimeUnit).
232   // TODO: Test enterIf(Guard, long, TimeUnit).
233   // TODO: Test waitFor(Guard, long, TimeUnit).
234   // TODO: Test getQueueLength().
235   // TODO: Test hasQueuedThreads().
236   // TODO: Test getWaitQueueLength(Guard).
237   // TODO: Test automatic signaling before leave, waitFor, and reentrant enterWhen.
238   // TODO: Test blocking to re-enter monitor after being signaled.
239   // TODO: Test interrupts with both interruptible and uninterruptible monitor.
240   // TODO: Test multiple waiters: If guard is still satisfied, signal next waiter.
241   // TODO: Test multiple waiters: If guard is no longer satisfied, do not signal next waiter.
242 
243 }
244