1/*
2 * Copyright (C) 2009 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
17package com.google.common.util.concurrent;
18
19import static com.google.common.base.Preconditions.checkNotNull;
20import static junit.framework.Assert.assertEquals;
21import static junit.framework.Assert.assertFalse;
22import static junit.framework.Assert.assertTrue;
23import static junit.framework.Assert.fail;
24
25import java.util.concurrent.CancellationException;
26import java.util.concurrent.CountDownLatch;
27import java.util.concurrent.ExecutionException;
28import java.util.concurrent.ExecutorService;
29import java.util.concurrent.Executors;
30import java.util.concurrent.TimeUnit;
31
32import javax.annotation.Nullable;
33
34/**
35 * Used to test listenable future implementations.
36 *
37 * @author Sven Mawson
38 */
39public class ListenableFutureTester {
40
41  private final ExecutorService exec;
42  private final ListenableFuture<?> future;
43  private final CountDownLatch latch;
44
45  public ListenableFutureTester(ListenableFuture<?> future) {
46    this.exec = Executors.newCachedThreadPool();
47    this.future = checkNotNull(future);
48    this.latch = new CountDownLatch(1);
49  }
50
51  public void setUp() {
52    future.addListener(new Runnable() {
53      @Override public void run() {
54        latch.countDown();
55      }
56    }, exec);
57
58    assertEquals(1, latch.getCount());
59    assertFalse(future.isDone());
60    assertFalse(future.isCancelled());
61  }
62
63  public void tearDown() {
64    exec.shutdown();
65  }
66
67  public void testCompletedFuture(@Nullable Object expectedValue)
68      throws InterruptedException, ExecutionException {
69    assertTrue(future.isDone());
70    assertFalse(future.isCancelled());
71
72    assertTrue(latch.await(5, TimeUnit.SECONDS));
73    assertTrue(future.isDone());
74    assertFalse(future.isCancelled());
75
76    assertEquals(expectedValue, future.get());
77  }
78
79  public void testCancelledFuture()
80      throws InterruptedException, ExecutionException {
81    assertTrue(future.isDone());
82    assertTrue(future.isCancelled());
83
84    assertTrue(latch.await(5, TimeUnit.SECONDS));
85    assertTrue(future.isDone());
86    assertTrue(future.isCancelled());
87
88    try {
89      future.get();
90      fail("Future should throw CancellationException on cancel.");
91    } catch (CancellationException expected) {}
92  }
93
94  public void testFailedFuture(@Nullable String message)
95      throws InterruptedException {
96    assertTrue(future.isDone());
97    assertFalse(future.isCancelled());
98
99    assertTrue(latch.await(5, TimeUnit.SECONDS));
100    assertTrue(future.isDone());
101    assertFalse(future.isCancelled());
102
103    try {
104      future.get();
105      fail("Future should rethrow the exception.");
106    } catch (ExecutionException e) {
107      assertEquals(message, e.getCause().getMessage());
108    }
109  }
110}
111