ReentrantEventsTest.java revision 7dd252788645e940eada959bdde927426e2531c9 
1/*
2 * Copyright (C) 2007 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.eventbus;
18
19import com.google.common.collect.Lists;
20
21import java.util.List;
22
23import junit.framework.TestCase;
24
25/**
26 * Validate that {@link EventBus} behaves carefully when listeners publish
27 * their own events.
28 *
29 * @author Jesse Wilson
30 */
31public class ReentrantEventsTest extends TestCase {
32
33  static final String FIRST = "one";
34  static final Double SECOND = 2.0d;
35
36  final EventBus bus = new EventBus();
37
38  public void testNoReentrantEvents() {
39    ReentrantEventsHater hater = new ReentrantEventsHater();
40    bus.register(hater);
41
42    bus.post(FIRST);
43
44    assertEquals("ReentrantEventHater expected 2 events",
45        Lists.<Object>newArrayList(FIRST, SECOND), hater.eventsReceived);
46  }
47
48  public class ReentrantEventsHater {
49    boolean ready = true;
50    List<Object> eventsReceived = Lists.newArrayList();
51
52    @Subscribe
53    public void listenForStrings(String event) {
54      eventsReceived.add(event);
55      ready = false;
56      try {
57        bus.post(SECOND);
58      } finally {
59        ready = true;
60      }
61    }
62
63    @Subscribe
64    public void listenForDoubles(Double event) {
65      assertTrue("I received an event when I wasn't ready!", ready);
66      eventsReceived.add(event);
67    }
68  }
69
70  public void testEventOrderingIsPredictable() {
71    EventProcessor processor = new EventProcessor();
72    bus.register(processor);
73
74    EventRecorder recorder = new EventRecorder();
75    bus.register(recorder);
76
77    bus.post(FIRST);
78
79    assertEquals("EventRecorder expected events in order",
80        Lists.<Object>newArrayList(FIRST, SECOND), recorder.eventsReceived);
81  }
82
83  public class EventProcessor {
84    @Subscribe public void listenForStrings(String event) {
85      bus.post(SECOND);
86    }
87  }
88
89  public class EventRecorder {
90    List<Object> eventsReceived = Lists.newArrayList();
91    @Subscribe public void listenForEverything(Object event) {
92      eventsReceived.add(event);
93    }
94  }
95}
96