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1 package org.shiftone.cache.policy.lru;
2
3
4
5 import org.shiftone.cache.util.*;
6 import org.shiftone.cache.util.reaper.ReapableCache;
7
8 import java.util.Map  ;
9
10
11
18 class LruCache extends AbstractPolicyCache implements ReapableCache
19 {
20
21 private static final Log LOG = new Log(LruCache.class);
22 private final Map map;
23 private final LinkedList fifo;
24 private final LinkedList lru;
25
26 LruCache(String name, long timeoutMilliSeconds, int maxSize)
27 {
28
29 super(name, timeoutMilliSeconds, maxSize);
30
31 map = MapFactory.createMap(maxSize);
32 fifo = new LinkedList();
33 lru = new LinkedList();
34 }
35
36
37 protected CacheNode findNodeByKey(Object key)
38 {
39 return (LruNode) map.get(key);
40 }
41
42
43 public int size()
44 {
45 return map.size();
46 }
47
48
49 protected void revalueNode(CacheNode node)
50 {
51
52 LruNode n = (LruNode) node;
53
54 lru.moveToFirst(n.lruNode);
55 }
56
57
58 protected void delete(CacheNode node)
59 {
60
61 LruNode n = (LruNode) node;
62
63 fifo.remove(n.fifoNode);
64 lru.remove(n.lruNode);
65 map.remove(n.key);
66 }
67
68
69 protected void removeLeastValuableNode()
70 {
71
72 LinkedListNode lln = null;
73 LruNode node = null;
74
75 lln = lru.peekLast();
76 node = (LruNode) lln.getValue();
77
78 delete(node);
79 }
80
81
82 public void removeExpiredElements()
83 {
84
85 LinkedListNode lln = null;
86 LruNode node = null;
87
88 while ((lln = fifo.peekLast()) != null)
89 {
90 node = (LruNode) lln.getValue();
91
92 if (node.isExpired())
93 {
94 delete(node);
95 }
96 else
97 {
98
99 break;
101 }
102 }
103 }
104
105
106 protected CacheNode createNode(Object userKey, Object cacheObject)
107 {
108
109 LruNode node = new LruNode();
110
111 node.key = userKey;
112 node.value = cacheObject;
113 node.fifoNode = fifo.addFirst(node);
114 node.lruNode = lru.addFirst(node);
115 node.timeoutTime = System.currentTimeMillis() + getTimeoutMilliSeconds();
116
117 map.put(userKey, node);
118
119 return node;
120 }
121
122
123 String dumpLruKeys()
124 {
125
126 String dump = null;
127 StringBuffer sb = new StringBuffer ();
128 LinkedListNode node = lru.peekFirst();
129 LruNode current = null;
130
131 while (node != null)
132 {
133 current = (LruNode) node.getValue();
134
135 sb.append(current.key);
136
137 node = node.getNext();
138 }
139
140 dump = sb.toString();
141
142 LOG.debug("dumpLruKeys : " + dump);
143
144 return dump;
145 }
146
147
148 String dumpFifoKeys()
149 {
150
151 String dump = null;
152 StringBuffer sb = new StringBuffer ();
153 LinkedListNode node = fifo.peekFirst();
154 LruNode current = null;
155
156 while (node != null)
157 {
158 current = (LruNode) node.getValue();
159
160 sb.append(current.key);
161
162 node = node.getNext();
163 }
164
165 dump = sb.toString();
166
167 LOG.debug("dumpFifoKeys : " + dump);
168
169 return dump;
170 }
171 }
172 |
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