1 /***
2 * Copyright 2003-2010 Terracotta, Inc.
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.concurrent;
18
19
20 import net.sf.ehcache.CacheException;
21
22 import static org.junit.Assert.assertTrue;
23
24 import org.junit.Test;
25
26
27 import org.slf4j.Logger;
28 import org.slf4j.LoggerFactory;
29
30
31 /***
32 * Isolation tests for ConcurrencyUtil
33 *
34 * @author Greg Luck
35 * @version $Id: ConcurrencyUtilTest.html 13146 2011-08-01 17:12:39Z oletizi $
36 */
37 public class ConcurrencyUtilTest {
38
39 private static final Logger LOG = LoggerFactory.getLogger(ConcurrencyUtilTest.class.getName());
40
41
42 /***
43 * Tests that stripes are evently distributed
44 */
45 @Test
46 public void testStripingDistribution() {
47
48 int[] lockIndexes = new int[2048];
49 for (int i = 0; i < 20480 * 3; i++) {
50 String key = "" + i * 3 / 2 + i;
51 key += key.hashCode();
52 int lock = ConcurrencyUtil.selectLock(key, 2048);
53 lockIndexes[lock]++;
54 }
55
56 int outliers = 0;
57 for (int i = 0; i < 2048; i++) {
58 if (20 <= lockIndexes[i] && lockIndexes[i] <= 40) {
59 continue;
60 }
61 LOG.info(i + ": " + lockIndexes[i]);
62 outliers++;
63 }
64 assertTrue(outliers <= 128);
65 }
66
67 /***
68 * Tests edge conditions for striping mechanism.
69 */
70 @Test
71 public void testNullKey() {
72 ConcurrencyUtil.selectLock(null, 2048);
73 ConcurrencyUtil.selectLock("", 2048);
74 }
75
76
77 /***
78 * Tests edge conditions for striping mechanism.
79 */
80 @Test
81 public void testEvenLockNumber() {
82 try {
83 ConcurrencyUtil.selectLock("anything", 100);
84 } catch (CacheException e) {
85
86 }
87 }
88
89
90 }