1 /*
2 * Licensed to the Apache Software Foundation (ASF) under one or more
3 * contributor license agreements. See the NOTICE file distributed with
4 * this work for additional information regarding copyright ownership.
5 * The ASF licenses this file to You under the Apache License, Version 2.0
6 * (the "License"); you may not use this file except in compliance with
7 * the License. You may obtain a copy of the License at
8 *
9 * http://www.apache.org/licenses/LICENSE-2.0
10 *
11 * Unless required by applicable law or agreed to in writing, software
12 * distributed under the License is distributed on an "AS IS" BASIS,
13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14 * See the License for the specific language governing permissions and
15 * limitations under the License.
16 */
17 package org.apache.commons.lang3.concurrent;
18
19 import static org.junit.jupiter.api.Assertions.assertEquals;
20 import static org.junit.jupiter.api.Assertions.assertFalse;
21 import static org.junit.jupiter.api.Assertions.assertNotNull;
22 import static org.junit.jupiter.api.Assertions.assertTrue;
23
24 import java.util.concurrent.CountDownLatch;
25
26 import org.apache.commons.lang3.AbstractLangTest;
27 import org.junit.jupiter.api.Test;
28
29 /**
30 * <p>
31 * An abstract base class for tests of concrete {@code ConcurrentInitializer}
32 * implementations.
33 * </p>
34 * <p>
35 * This class provides some basic tests for initializer implementations. Derived
36 * class have to create a {@link ConcurrentInitializer} object on which the
37 * tests are executed.
38 * </p>
39 */
40 public abstract class AbstractConcurrentInitializerTest extends AbstractLangTest {
41 /**
42 * Creates the {@link ConcurrentInitializer} object to be tested. This
43 * method is called whenever the test fixture needs to be obtained.
44 *
45 * @return the initializer object to be tested
46 */
47 protected abstract ConcurrentInitializer<Object> createInitializer();
48
49 /**
50 * Tests a simple invocation of the get() method.
51 *
52 * @throws org.apache.commons.lang3.concurrent.ConcurrentException because the object under test may throw it.
53 */
54 @Test
55 public void testGet() throws ConcurrentException {
56 assertNotNull(createInitializer().get(), "No managed object");
57 }
58
59 /**
60 * Tests whether get() can be invoked from multiple threads concurrently.
61 * Always the same object should be returned.
62 *
63 * @throws org.apache.commons.lang3.concurrent.ConcurrentException because the object under test may throw it.
64 * @throws InterruptedException because the threading API my throw it.
65 */
66 @Test
67 public void testGetConcurrent() throws ConcurrentException,
68 InterruptedException {
69 final ConcurrentInitializer<Object> initializer = createInitializer();
70 final int threadCount = 20;
71 final CountDownLatch startLatch = new CountDownLatch(1);
72 final class GetThread extends Thread {
73 Object object;
74
75 @Override
76 public void run() {
77 try {
78 // wait until all threads are ready for maximum parallelism
79 startLatch.await();
80 // access the initializer
81 object = initializer.get();
82 } catch (final InterruptedException iex) {
83 // ignore
84 } catch (final ConcurrentException cex) {
85 object = cex;
86 }
87 }
88 }
89
90 final GetThread[] threads = new GetThread[threadCount];
91 for (int i = 0; i < threadCount; i++) {
92 threads[i] = new GetThread();
93 threads[i].start();
94 }
95
96 // fire all threads and wait until they are ready
97 startLatch.countDown();
98 for (final Thread t : threads) {
99 t.join();
100 }
101
102 // check results
103 final Object managedObject = initializer.get();
104 for (final GetThread t : threads) {
105 assertEquals(managedObject, t.object, "Wrong object");
106 }
107 }
108
109 /**
110 * Tests whether sequential get() invocations always return the same
111 * instance.
112 *
113 * @throws org.apache.commons.lang3.concurrent.ConcurrentException because the object under test may throw it.
114 */
115 @Test
116 public void testGetMultipleTimes() throws ConcurrentException {
117 final ConcurrentInitializer<Object> initializer = createInitializer();
118 final Object obj = initializer.get();
119 for (int i = 0; i < 10; i++) {
120 assertEquals(obj, initializer.get(), "Got different object at " + i);
121 }
122 }
123
124 /**
125 * Tests a simple invocation of the isInitialized() method.
126 */
127 @Test
128 public void testisInitialized() throws Throwable {
129 final ConcurrentInitializer<Object> initializer = createInitializer();
130 if (initializer instanceof AbstractConcurrentInitializer) {
131 AbstractConcurrentInitializer castedInitializer = (AbstractConcurrentInitializer) initializer;
132 assertFalse(castedInitializer.isInitialized(), "was initialized before get()");
133 assertNotNull(castedInitializer.get(), "No managed object");
134 assertTrue(castedInitializer.isInitialized(), "was not initialized after get()");
135 }
136 }
137 }