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