KickJava   Java API By Example, From Geeks To Geeks.

Java > Open Source Codes > net > sf > dozer > util > mapping > cache > Cache


1 /*
2  * Copyright 2005-2007 the original author or authors.
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 package net.sf.dozer.util.mapping.cache;
17
18 import java.util.Collection JavaDoc;
19 import java.util.Map JavaDoc;
20
21 import net.sf.dozer.util.mapping.stats.GlobalStatistics;
22 import net.sf.dozer.util.mapping.stats.StatisticTypeConstants;
23 import net.sf.dozer.util.mapping.stats.StatisticsManagerIF;
24
25 import org.apache.commons.collections.map.LinkedMap;
26 import org.apache.commons.lang.builder.ReflectionToStringBuilder;
27 import org.apache.commons.lang.builder.ToStringStyle;
28
29 /**
30  * @author tierney.matt
31  */
32 public class Cache {
33   private final String JavaDoc name;
34
35   private long maximumSize;
36   private final Map JavaDoc cacheMap;
37   private long hitCount;
38   private long missCount;
39
40   public Cache(String JavaDoc name, long maximumSize) {
41     this.name = name;
42     this.maximumSize = maximumSize;
43     this.cacheMap = new CacheLinkedHashMap();
44   }
45   
46   public void clear() {
47     cacheMap.clear();
48   }
49
50   public synchronized void put(CacheEntry cacheEntry) {
51     if (cacheEntry == null) {
52       throw new IllegalArgumentException JavaDoc("Cache Entry cannot be null");
53     }
54     cacheMap.put(cacheEntry.getKey(), cacheEntry);
55     if (cacheMap.size() > maximumSize) {
56       // remove eldest entry
57 ((LinkedMap) cacheMap).remove(cacheMap.size() - 1);
58     }
59   }
60
61   public CacheEntry get(Object JavaDoc key) {
62     if (key == null) {
63       throw new IllegalArgumentException JavaDoc("Key cannot be null");
64     }
65     CacheEntry result = (CacheEntry) cacheMap.get(key);
66     StatisticsManagerIF statMgr = GlobalStatistics.getInstance().getStatsMgr();
67     if (result != null) {
68       hitCount++;
69       statMgr.increment(StatisticTypeConstants.CACHE_HIT_COUNT, name);
70     } else {
71       missCount++;
72       statMgr.increment(StatisticTypeConstants.CACHE_MISS_COUNT, name);
73     }
74     return result;
75   }
76   
77   public Collection JavaDoc getEntries() {
78     return cacheMap.values();
79   }
80
81   public String JavaDoc getName() {
82     return name;
83   }
84
85   public int getSize() {
86     return cacheMap.size();
87   }
88   
89   public long getMaxSize() {
90     return maximumSize;
91   }
92   
93   public void setMaxSize(long maximumSize) {
94     this.maximumSize = maximumSize;
95   }
96   
97   public long getHitCount() {
98     return hitCount;
99   }
100
101   public long getMissCount() {
102     return missCount;
103   }
104
105   public String JavaDoc toString() {
106     return ReflectionToStringBuilder.toString(this, ToStringStyle.MULTI_LINE_STYLE);
107   }
108
109   private class CacheLinkedHashMap extends LinkedMap {
110     // Order the map by which its entries were last accessed, from least-recently accessed to most-recently
111 // (access-order)
112 public CacheLinkedHashMap() {
113       super(100, 0.75F);
114     }
115   }
116
117 }
118
Popular Tags