1 /**
2 * Copyright 2003-2007 Greg Luck
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 package net.sf.ehcache.constructs.concurrent;
18
19 import junit.framework.TestCase;
20 import net.sf.ehcache.CacheException;
21 import org.apache.commons.logging.Log;
22 import org.apache.commons.logging.LogFactory;
23
24 /**
25 * Isolation tests for ConcurrencyUtil
26 *
27 * @author Greg Luck
28 * @version $Id: ConcurrencyUtilTest.java 512 2007-07-10 09:18:45Z gregluck $
29 */
30 public class ConcurrencyUtilTest extends TestCase {
31
32 private static final Log LOG = LogFactory.getLog(ConcurrencyUtilTest.class.getName());
33
34
35 /**
36 * Tests that stripes are evently distributed
37 */
38 public void testStripingDistribution() {
39
40 int[] lockIndexes = new int[2048];
41 for (int i = 0; i < 20480 * 3; i++) {
42 String key = "" + i * 3 / 2 + i;
43 key += key.hashCode();
44 int lock = ConcurrencyUtil.selectLock(key, 2048);
45 lockIndexes[lock]++;
46 }
47
48 int outliers = 0;
49 for (int i = 0; i < 2048; i++) {
50 if (20 <= lockIndexes[i] && lockIndexes[i] <= 40) {
51 continue;
52 }
53 LOG.info(i + ": " + lockIndexes[i]);
54 outliers++;
55 }
56 assertTrue(outliers <= 128);
57 }
58
59 /**
60 * Tests edge conditions for striping mechanism.
61 */
62 public void testNullKey() {
63 ConcurrencyUtil.selectLock(null, 2048);
64 ConcurrencyUtil.selectLock("", 2048);
65 }
66
67
68 /**
69 * Tests edge conditions for striping mechanism.
70 */
71 public void testEvenLockNumber() {
72 try {
73 ConcurrencyUtil.selectLock("anything", 100);
74 } catch (CacheException e) {
75 //expected
76 }
77 }
78
79
80 }