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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.configuration.event;
18  
19  import static org.junit.Assert.assertEquals;
20  import static org.junit.Assert.assertFalse;
21  import static org.junit.Assert.assertTrue;
22  
23  import java.util.Collection;
24  
25  import org.junit.Before;
26  import org.junit.Test;
27  
28  /**
29   * Test class for EventSource.
30   *
31   * @version $Id: TestEventSource.java 1225652 2011-12-29 21:00:57Z oheger $
32   */
33  public class TestEventSource
34  {
35      /** Constant for the event type used for testing. */
36      static final int TEST_TYPE = 42;
37  
38      /** Constant for the event property name. */
39      static final String TEST_PROPNAME = "test.property.name";
40  
41      /** Constant for the event property value. */
42      static final Object TEST_PROPVALUE = "a test property value";
43  
44      /** The object under test. */
45      CountingEventSource source;
46  
47      @Before
48      public void setUp() throws Exception
49      {
50          source = new CountingEventSource();
51      }
52  
53      /**
54       * Tests a newly created source object.
55       */
56      @Test
57      public void testInit()
58      {
59          assertTrue("Listeners list is not empty", source
60                  .getConfigurationListeners().isEmpty());
61          assertFalse("Removing listener", source
62                  .removeConfigurationListener(new TestListener()));
63          assertFalse("Detail events are enabled", source.isDetailEvents());
64          assertTrue("Error listeners list is not empty", source
65                  .getErrorListeners().isEmpty());
66      }
67  
68      /**
69       * Tests registering a new listener.
70       */
71      @Test
72      public void testAddConfigurationListener()
73      {
74          TestListener l = new TestListener();
75          source.addConfigurationListener(l);
76          Collection<ConfigurationListener> listeners = source.getConfigurationListeners();
77          assertEquals("Wrong number of listeners", 1, listeners.size());
78          assertTrue("Listener not in list", listeners.contains(l));
79      }
80  
81      /**
82       * Tests adding an undefined configuration listener. This should cause an
83       * exception.
84       */
85      @Test(expected = IllegalArgumentException.class)
86      public void testAddNullConfigurationListener()
87      {
88          source.addConfigurationListener(null);
89      }
90  
91      /**
92       * Tests removing a listener.
93       */
94      @Test
95      public void testRemoveConfigurationListener()
96      {
97          TestListener l = new TestListener();
98          assertFalse("Listener can be removed?", source
99                  .removeConfigurationListener(l));
100         source.addConfigurationListener(l);
101         source.addConfigurationListener(new TestListener());
102         assertFalse("Unknown listener can be removed", source
103                 .removeConfigurationListener(new TestListener()));
104         assertTrue("Could not remove listener", source
105                 .removeConfigurationListener(l));
106         assertFalse("Listener still in list", source
107                 .getConfigurationListeners().contains(l));
108     }
109 
110     /**
111      * Tests if a null listener can be removed. This should be a no-op.
112      */
113     @Test
114     public void testRemoveNullConfigurationListener()
115     {
116         source.addConfigurationListener(new TestListener());
117         assertFalse("Null listener can be removed", source
118                 .removeConfigurationListener(null));
119         assertEquals("Listener list was modified", 1, source
120                 .getConfigurationListeners().size());
121     }
122 
123     /**
124      * Tests whether the listeners list is read only.
125      */
126     @Test(expected = UnsupportedOperationException.class)
127     public void testGetConfigurationListenersUpdate()
128     {
129         source.addConfigurationListener(new TestListener());
130         Collection<ConfigurationListener> list = source.getConfigurationListeners();
131         list.clear();
132     }
133 
134     /**
135      * Tests that the collection returned by getConfigurationListeners() is
136      * really a snapshot. A later added listener must not be visible.
137      */
138     @Test
139     public void testGetConfigurationListenersAddNew()
140     {
141         Collection<ConfigurationListener> list = source.getConfigurationListeners();
142         source.addConfigurationListener(new TestListener());
143         assertTrue("Listener snapshot not empty", list.isEmpty());
144     }
145 
146     /**
147      * Tests enabling and disabling the detail events flag.
148      */
149     @Test
150     public void testSetDetailEvents()
151     {
152         source.setDetailEvents(true);
153         assertTrue("Detail events are disabled", source.isDetailEvents());
154         source.setDetailEvents(true);
155         source.setDetailEvents(false);
156         assertTrue("Detail events are disabled again", source.isDetailEvents());
157         source.setDetailEvents(false);
158         assertFalse("Detail events are still enabled", source.isDetailEvents());
159     }
160 
161     /**
162      * Tests delivering an event to a listener.
163      */
164     @Test
165     public void testFireEvent()
166     {
167         TestListener l = new TestListener();
168         source.addConfigurationListener(l);
169         source.fireEvent(TEST_TYPE, TEST_PROPNAME, TEST_PROPVALUE, true);
170         assertEquals("Not 1 event created", 1, source.eventCount);
171         assertEquals("Listener not called once", 1, l.numberOfCalls);
172         assertEquals("Wrong event type", TEST_TYPE, l.lastEvent.getType());
173         assertEquals("Wrong property name", TEST_PROPNAME, l.lastEvent
174                 .getPropertyName());
175         assertEquals("Wrong property value", TEST_PROPVALUE, l.lastEvent
176                 .getPropertyValue());
177         assertTrue("Wrong before event flag", l.lastEvent.isBeforeUpdate());
178     }
179 
180     /**
181      * Tests firing an event if there are no listeners.
182      */
183     @Test
184     public void testFireEventNoListeners()
185     {
186         source.fireEvent(TEST_TYPE, TEST_PROPNAME, TEST_PROPVALUE, false);
187         assertEquals("An event object was created", 0, source.eventCount);
188     }
189 
190     /**
191      * Tests generating a detail event if detail events are not allowed.
192      */
193     @Test
194     public void testFireEventNoDetails()
195     {
196         TestListener l = new TestListener();
197         source.addConfigurationListener(l);
198         source.setDetailEvents(false);
199         source.fireEvent(TEST_TYPE, TEST_PROPNAME, TEST_PROPVALUE, false);
200         assertEquals("Event object was created", 0, source.eventCount);
201         assertEquals("Listener was called", 0, l.numberOfCalls);
202     }
203 
204     /**
205      * Tests whether an event listener can deregister itself in reaction of a
206      * delivered event.
207      */
208     @Test
209     public void testRemoveListenerInFireEvent()
210     {
211         ConfigurationListener lstRemove = new ConfigurationListener()
212         {
213             public void configurationChanged(ConfigurationEvent event)
214             {
215                 source.removeConfigurationListener(this);
216             }
217         };
218 
219         source.addConfigurationListener(lstRemove);
220         TestListener l = new TestListener();
221         source.addConfigurationListener(l);
222         source.fireEvent(TEST_TYPE, TEST_PROPNAME, TEST_PROPVALUE, false);
223         assertEquals("Listener was not called", 1, l.numberOfCalls);
224         assertEquals("Listener was not removed", 1, source
225                 .getConfigurationListeners().size());
226     }
227 
228     /**
229      * Tests registering a new error listener.
230      */
231     @Test
232     public void testAddErrorListener()
233     {
234         TestListener l = new TestListener();
235         source.addErrorListener(l);
236         Collection<ConfigurationErrorListener> listeners = source.getErrorListeners();
237         assertEquals("Wrong number of listeners", 1, listeners.size());
238         assertTrue("Listener not in list", listeners.contains(l));
239     }
240 
241     /**
242      * Tests adding an undefined error listener. This should cause an exception.
243      */
244     @Test(expected = IllegalArgumentException.class)
245     public void testAddNullErrorListener()
246     {
247         source.addErrorListener(null);
248     }
249 
250     /**
251      * Tests removing an error listener.
252      */
253     @Test
254     public void testRemoveErrorListener()
255     {
256         TestListener l = new TestListener();
257         assertFalse("Listener can be removed?", source.removeErrorListener(l));
258         source.addErrorListener(l);
259         source.addErrorListener(new TestListener());
260         assertFalse("Unknown listener can be removed", source
261                 .removeErrorListener(new TestListener()));
262         assertTrue("Could not remove listener", source.removeErrorListener(l));
263         assertFalse("Listener still in list", source.getErrorListeners()
264                 .contains(l));
265     }
266 
267     /**
268      * Tests if a null error listener can be removed. This should be a no-op.
269      */
270     @Test
271     public void testRemoveNullErrorListener()
272     {
273         source.addErrorListener(new TestListener());
274         assertFalse("Null listener can be removed", source
275                 .removeErrorListener(null));
276         assertEquals("Listener list was modified", 1, source
277                 .getErrorListeners().size());
278     }
279 
280     /**
281      * Tests whether the listeners list is read only.
282      */
283     @Test(expected = UnsupportedOperationException.class)
284     public void testGetErrorListenersUpdate()
285     {
286         source.addErrorListener(new TestListener());
287         Collection<ConfigurationErrorListener> list = source.getErrorListeners();
288         list.clear();
289     }
290 
291     /**
292      * Tests delivering an error event to a listener.
293      */
294     @Test
295     public void testFireError()
296     {
297         TestListener l = new TestListener();
298         source.addErrorListener(l);
299         Exception testException = new Exception("A test");
300         source.fireError(TEST_TYPE, TEST_PROPNAME, TEST_PROPVALUE,
301                 testException);
302         assertEquals("Not 1 event created", 1, source.errorCount);
303         assertEquals("Error listener not called once", 1, l.numberOfErrors);
304         assertEquals("Normal event was generated", 0, l.numberOfCalls);
305         assertEquals("Wrong event type", TEST_TYPE, l.lastEvent.getType());
306         assertEquals("Wrong property name", TEST_PROPNAME, l.lastEvent
307                 .getPropertyName());
308         assertEquals("Wrong property value", TEST_PROPVALUE, l.lastEvent
309                 .getPropertyValue());
310         assertEquals("Wrong Throwable object", testException,
311                 ((ConfigurationErrorEvent) l.lastEvent).getCause());
312     }
313 
314     /**
315      * Tests firing an error event if there are no error listeners.
316      */
317     @Test
318     public void testFireErrorNoListeners()
319     {
320         source.fireError(TEST_TYPE, TEST_PROPNAME, TEST_PROPVALUE,
321                 new Exception());
322         assertEquals("An error event object was created", 0, source.errorCount);
323     }
324 
325     /**
326      * Tests cloning an event source object. The registered listeners should not
327      * be registered at the clone.
328      */
329     @Test
330     public void testClone() throws CloneNotSupportedException
331     {
332         source.addConfigurationListener(new TestListener());
333         source.addErrorListener(new TestListener());
334         EventSource copy = (EventSource) source.clone();
335         assertTrue("Configuration listeners registered for clone", copy
336                 .getConfigurationListeners().isEmpty());
337         assertTrue("Error listeners registered for clone", copy
338                 .getErrorListeners().isEmpty());
339     }
340 
341     /**
342      * A test event listener implementation.
343      */
344     static class TestListener implements ConfigurationListener,
345             ConfigurationErrorListener
346     {
347         ConfigurationEvent lastEvent;
348 
349         int numberOfCalls;
350 
351         int numberOfErrors;
352 
353         public void configurationChanged(ConfigurationEvent event)
354         {
355             lastEvent = event;
356             numberOfCalls++;
357         }
358 
359         public void configurationError(ConfigurationErrorEvent event)
360         {
361             lastEvent = event;
362             numberOfErrors++;
363         }
364     }
365 
366     /**
367      * A specialized event source implementation that counts the number of
368      * created event objects. It is used to test whether the
369      * {@code fireEvent()} methods only creates event objects if
370      * necessary. It also allows testing the clone() operation.
371      */
372     static class CountingEventSource extends EventSource implements Cloneable
373     {
374         int eventCount;
375 
376         int errorCount;
377 
378         @Override
379         protected ConfigurationEvent createEvent(int type, String propName,
380                 Object propValue, boolean before)
381         {
382             eventCount++;
383             return super.createEvent(type, propName, propValue, before);
384         }
385 
386         @Override
387         protected ConfigurationErrorEvent createErrorEvent(int type,
388                 String propName, Object value, Throwable ex)
389         {
390             errorCount++;
391             return super.createErrorEvent(type, propName, value, ex);
392         }
393     }
394 }