Java > Open Source Codes > org > apache > commons > logging > impl > WeakHashtableTest


1 /*
2  * Copyright 2004 The Apache Software Foundation.
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
17
18 package org.apache.commons.logging.impl;
19
20 import java.lang.ref.*;
21 import junit.framework.*;
22 import java.util.*;
23
24 public class WeakHashtableTest extends TestCase {
25
26     
27     /** Maximum number of iterations before our test fails */
28     private static final int MAX_GC_ITERATIONS = 50;
29
30     private WeakHashtable weakHashtable;
31     private Long keyOne;
32     private Long keyTwo;
33     private Long keyThree;
34     private Long valueOne;
35     private Long valueTwo;
36     private Long valueThree;
37
38     public WeakHashtableTest(String testName) {
39         super(testName);
40     }
41     
42
43     protected void setUp() throws Exception {
44         super.setUp();
45         weakHashtable = new WeakHashtable();
46         
47         keyOne = new Long (1);
48         keyTwo = new Long (2);
49         keyThree = new Long (3);
50         valueOne = new Long (100);
51         valueTwo = new Long (200);
52         valueThree = new Long (300);
53         
54         weakHashtable.put(keyOne, valueOne);
55         weakHashtable.put(keyTwo, valueTwo);
56         weakHashtable.put(keyThree, valueThree);
57     }
58
59     /** Tests public boolean contains(ObjectÊvalue) */
60     public void testContains() throws Exception {
61         assertFalse(weakHashtable.contains(new Long (1)));
62         assertFalse(weakHashtable.contains(new Long (2)));
63         assertFalse(weakHashtable.contains(new Long (3)));
64         assertTrue(weakHashtable.contains(new Long (100)));
65         assertTrue(weakHashtable.contains(new Long (200)));
66         assertTrue(weakHashtable.contains(new Long (300)));
67         assertFalse(weakHashtable.contains(new Long (400)));
68     }
69     
70     /** Tests public boolean containsKey(ObjectÊkey) */
71     public void testContainsKey() throws Exception {
72         assertTrue(weakHashtable.containsKey(new Long (1)));
73         assertTrue(weakHashtable.containsKey(new Long (2)));
74         assertTrue(weakHashtable.containsKey(new Long (3)));
75         assertFalse(weakHashtable.containsKey(new Long (100)));
76         assertFalse(weakHashtable.containsKey(new Long (200)));
77         assertFalse(weakHashtable.containsKey(new Long (300)));
78         assertFalse(weakHashtable.containsKey(new Long (400)));
79     }
80     
81     /** Tests public boolean containsValue(ObjectÊvalue) */
82     public void testContainsValue() throws Exception {
83         assertFalse(weakHashtable.containsValue(new Long (1)));
84         assertFalse(weakHashtable.containsValue(new Long (2)));
85         assertFalse(weakHashtable.containsValue(new Long (3)));
86         assertTrue(weakHashtable.containsValue(new Long (100)));
87         assertTrue(weakHashtable.containsValue(new Long (200)));
88         assertTrue(weakHashtable.containsValue(new Long (300)));
89         assertFalse(weakHashtable.containsValue(new Long (400)));
90     }
91     
92     /** Tests public Enumeration elements() */
93     public void testElements() throws Exception {
94         ArrayList elements = new ArrayList();
95         for (Enumeration e = weakHashtable.elements(); e.hasMoreElements();) {
96             elements.add(e.nextElement());
97         }
98         assertEquals(3, elements.size());
99         assertTrue(elements.contains(valueOne));
100         assertTrue(elements.contains(valueTwo));
101         assertTrue(elements.contains(valueThree));
102     }
103     
104     /** Tests public Set entrySet() */
105     public void testEntrySet() throws Exception {
106         Set entrySet = weakHashtable.entrySet();
107         for (Iterator it = entrySet.iterator(); it.hasNext();) {
108             Map.Entry entry = (Map.Entry) it.next();
109             Object key = entry.getKey();
110             if (keyOne.equals(key)) {
111                 assertEquals(valueOne, entry.getValue());
112             } else if (keyTwo.equals(key)) {
113                 assertEquals(valueTwo, entry.getValue());
114             } else if (keyThree.equals(key)) {
115                 assertEquals(valueThree, entry.getValue());
116             } else {
117                 fail("Unexpected key");
118             }
119         }
120     }
121     
122     /** Tests public Object get(ObjectÊkey) */
123     public void testGet() throws Exception {
124         assertEquals(valueOne, weakHashtable.get(keyOne));
125         assertEquals(valueTwo, weakHashtable.get(keyTwo));
126         assertEquals(valueThree, weakHashtable.get(keyThree));
127         assertNull(weakHashtable.get(new Long (50)));
128     }
129     
130     /** Tests public Enumeration keys() */
131     public void testKeys() throws Exception {
132         ArrayList keys = new ArrayList();
133         for (Enumeration e = weakHashtable.keys(); e.hasMoreElements();) {
134             keys.add(e.nextElement());
135         }
136         assertEquals(3, keys.size());
137         assertTrue(keys.contains(keyOne));
138         assertTrue(keys.contains(keyTwo));
139         assertTrue(keys.contains(keyThree));
140     }
141     
142     /** Tests public Set keySet() */
143     public void testKeySet() throws Exception {
144         Set keySet = weakHashtable.keySet();
145         assertEquals(3, keySet.size());
146         assertTrue(keySet.contains(keyOne));
147         assertTrue(keySet.contains(keyTwo));
148         assertTrue(keySet.contains(keyThree));
149     }
150     
151     /** Tests public Object put(ObjectÊkey, ObjectÊvalue) */
152     public void testPut() throws Exception {
153         Long anotherKey = new Long (2004);
154         weakHashtable.put(anotherKey, new Long (1066));
155         
156         assertEquals(new Long (1066), weakHashtable.get(anotherKey));
157                
158         // Test compliance with the hashtable API re nulls
159 Exception caught = null;
160         try {
161             weakHashtable.put(null, new Object ());
162         }
163         catch (Exception e) {
164             caught = e;
165         }
166         assertNotNull("did not throw an exception adding a null key", caught);
167         caught = null;
168         try {
169             weakHashtable.put(new Object (), null);
170         }
171         catch (Exception e) {
172             caught = e;
173         }
174         assertNotNull("did not throw an exception adding a null value", caught);
175     }
176     
177     /** Tests public void putAll(MapÊt) */
178     public void testPutAll() throws Exception {
179         Map newValues = new HashMap();
180         Long newKey = new Long (1066);
181         Long newValue = new Long (1415);
182         newValues.put(newKey, newValue);
183         Long anotherNewKey = new Long (1645);
184         Long anotherNewValue = new Long (1815);
185         newValues.put(anotherNewKey, anotherNewValue);
186         weakHashtable.putAll(newValues);
187         
188         assertEquals(5, weakHashtable.size());
189         assertEquals(newValue, weakHashtable.get(newKey));
190         assertEquals(anotherNewValue, weakHashtable.get(anotherNewKey));
191     }
192     
193     /** Tests public Object remove(ObjectÊkey) */
194     public void testRemove() throws Exception {
195         weakHashtable.remove(keyOne);
196         assertEquals(2, weakHashtable.size());
197         assertNull(weakHashtable.get(keyOne));
198     }
199     
200     /** Tests public Collection values() */
201     public void testValues() throws Exception {
202         Collection values = weakHashtable.values();
203         assertEquals(3, values.size());
204         assertTrue(values.contains(valueOne));
205         assertTrue(values.contains(valueTwo));
206         assertTrue(values.contains(valueThree));
207     }
208     
209     public void testRelease() throws Exception {
210         assertNotNull(weakHashtable.get(new Long (1)));
211         ReferenceQueue testQueue = new ReferenceQueue();
212         WeakReference weakKeyOne = new WeakReference(keyOne, testQueue);
213
214         // lose our references
215 keyOne = null;
216         keyTwo = null;
217         keyThree = null;
218         valueOne = null;
219         valueTwo = null;
220         valueThree = null;
221         
222         int iterations = 0;
223         int bytz = 2;
224         while(true) {
225             System.gc();
226             if(iterations++ > MAX_GC_ITERATIONS){
227                 fail("Max iterations reached before resource released.");
228             }
229             
230             if(weakHashtable.get(new Long (1)) == null) {
231                 break;
232                 
233             } else {
234                 // create garbage:
235 byte[] b = new byte[bytz];
236                 bytz = bytz * 2;
237             }
238         }
239         
240         // some JVMs seem to take a little time to put references on
241 // the reference queue once the reference has been collected
242 // need to think about whether this is enough to justify
243 // stepping through the collection each time...
244 while(testQueue.poll() == null) {}
245         
246         // Test that the released objects are not taking space in the table
247 assertEquals("underlying table not emptied", 0, weakHashtable.size());
248     }
249 }
250

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