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.constructs.blocking;
18
19 import net.sf.ehcache.Element;
20
21 import java.util.Random;
22
23 /***
24 * A cache entry factory that counts the number of entries it has created.
25 * <p/>
26 * This is useful for writing tests.
27 *
28 * @author Greg Luck
29 * @version $Id: CountingCacheEntryFactory.html 13146 2011-08-01 17:12:39Z oletizi $
30 */
31 public class CountingCacheEntryFactory implements UpdatingCacheEntryFactory {
32
33 private int count;
34 private final Object value;
35 private Random random;
36
37 /***
38 * Creates a new instance
39 *
40 * @param value the factory always creates values equal to this value
41 */
42 public CountingCacheEntryFactory(final Object value) {
43 this.value = value;
44 random = new Random();
45 }
46
47 /***
48 * Fetches an entry.
49 */
50 public Object createEntry(final Object key) {
51 count++;
52 if (random.nextInt(2) == 1) {
53 return value;
54 } else {
55 return new Element(key, value);
56 }
57 }
58
59 /***
60 * @return number of entries the factory has created.
61 */
62 public int getCount() {
63 return count;
64 }
65
66 /***
67 * Perform an incremental update of data within a CacheEntry.
68 * Based on identification of dirty values within a CacheEntry
69 * Insert Update or Delete those entries based on the existing value.
70 * <p/>
71 * This method does not return a modified value, because it modifies the value passed into it, relying
72 * on the pass by reference feature of Java.
73 * <p/>
74 * Implementations of this method must be thread safe.
75 *
76 * @param key the cache Key
77 * @param value a value copied from the value that belonged to the Element in the cache. Value must be mutable
78 * @throws Exception
79 */
80 public void updateEntryValue(Object key, Object value) throws Exception {
81 count++;
82 if (key.equals("explode") && count > 1) {
83 throw new RuntimeException("EXPLODE!");
84 }
85 }
86
87 }