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1
8 package org.jboss.cache.eviction;
9
10 import org.apache.commons.logging.Log;
11 import org.apache.commons.logging.LogFactory;
12 import org.jboss.cache.Region;
13
14 import java.util.Iterator  ;
15
16
23 public class LRUAlgorithm extends BaseEvictionAlgorithm implements EvictionAlgorithm
24 {
25 private static final Log log = LogFactory.getLog(LRUAlgorithm.class);
26
27 public LRUAlgorithm()
28 {
29 super();
30 }
31
32 protected EvictionQueue setupEvictionQueue(Region region) throws EvictionException
33 {
34 return new LRUQueue();
35 }
36
37 protected boolean shouldEvictNode(NodeEntry entry)
38 {
39 LRUConfiguration config = (LRUConfiguration) region.getEvictionPolicyConfig();
40 if (config.getTimeToLiveSeconds() == 0 && config.getMaxAgeSeconds() == 0) return false;
42
43 long currentTime = System.currentTimeMillis();
44 if (config.getTimeToLiveSeconds() != 0)
45 {
46 long idleTime = currentTime - entry.getModifiedTimeStamp();
47 if (log.isTraceEnabled())
48 {
49 log.trace("Node " + entry.getFqn() + " has been idle for " + idleTime + "ms");
50 }
51 if ((idleTime >= (config.getTimeToLiveSeconds() * 1000)))
52 {
53 if (log.isTraceEnabled())
54 {
55 log.trace("Node " + entry.getFqn() + " should be evicted because of idle time");
56 }
57 return true;
58 }
59 }
60
61 if (config.getMaxAgeSeconds() != 0)
62 {
63 long objectLifeTime = currentTime - entry.getCreationTimeStamp();
64 if (log.isTraceEnabled())
65 {
66 log.trace("Node " + entry.getFqn() + " has been alive for " + objectLifeTime + "ms");
67 }
68 if ((objectLifeTime >= (config.getMaxAgeSeconds() * 1000)))
69 {
70 if (log.isTraceEnabled())
71 {
72 log.trace("Node " + entry.getFqn() + " should be evicted because of max age");
73 }
74 return true;
75 }
76 }
77
78 if (log.isTraceEnabled())
79 {
80 log.trace("Node " + entry.getFqn() + " should not be evicted");
81 }
82 return false;
83 }
84
85 protected void evict(NodeEntry ne)
86 {
87 if (ne != null)
89 {
90 if (!this.evictCacheNode(ne.getFqn()))
92 {
93 try
94 {
95 recycleQueue.put(ne.getFqn());
96 }
97 catch (InterruptedException e)
98 {
99 log.debug("InterruptedException", e);
100 }
101 }
102 }
103 }
104
105 protected void prune() throws EvictionException
106 {
107 LRUQueue lruQueue = (LRUQueue) evictionQueue;
108 NodeEntry ne;
109 Iterator it = lruQueue.iterateLRUQueue();
110 while (it.hasNext())
111 {
112 ne = (NodeEntry) it.next();
113 if (isNodeInUseAndNotTimedOut(ne))
114 {
115 continue;
116 }
117
118 if (this.shouldEvictNode(ne))
119 {
120 it.remove();
121 lruQueue.removeNodeEntryFromMaxAge(ne);
122 this.evict(ne);
123 }
124 else
125 {
126 break;
127 }
128 }
129
130 it = lruQueue.iterateMaxAgeQueue();
131 while (it.hasNext())
132 {
133 ne = (NodeEntry) it.next();
134 if (isNodeInUseAndNotTimedOut(ne))
135 {
136 continue;
137 }
138
139 if (this.shouldEvictNode(ne))
140 {
141 it.remove();
142 lruQueue.removeNodeEntryFromLRU(ne);
143 this.evict(ne);
144 }
145 else
146 {
147 break;
148 }
149 }
150
151 int maxNodes = this.getConfiguration().getMaxNodes();
152 if (maxNodes <= 0)
153 {
154 return;
155 }
156
157 it = lruQueue.iterateLRUQueue();
158 while (evictionQueue.getNumberOfNodes() > maxNodes)
159 {
160 ne = (NodeEntry) it.next();
161 if (log.isTraceEnabled())
162 {
163 log.trace("Node " + ne.getFqn() + " will be evicted because of exceeding the maxNode limit." +
164 " maxNode: " + maxNodes + " but current queue size is: " + evictionQueue.getNumberOfNodes());
165 }
166
167 if (!this.isNodeInUseAndNotTimedOut(ne))
168 {
169 it.remove();
170 lruQueue.removeNodeEntryFromMaxAge(ne);
171 this.evict(ne);
172 }
173 }
174 }
175
176 protected LRUConfiguration getConfiguration()
177 {
178 return (LRUConfiguration) region.getEvictionPolicyConfig();
179 }
180
181 }
182 |
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