|
1
5
6
7
14
15 package org.joseki.util.cache;
16
17 import java.util.* ;
18 import org.apache.commons.logging.*;
19
20 public class Cache
21 {
22 static Log log = LogFactory.getLog(Cache.class.getName()) ;
23
24 Map objects = new HashMap() ;
25 CacheItemFactory factory = null ;
26 CachePolicy policy = null ;
27 int size ;
28
29 public Cache(int _size, CacheItemFactory _factory, CachePolicy _policy)
30 {
31 factory = _factory ;
32 policy = _policy ;
33 size = _size ;
34 }
35
36 public synchronized void remove(Object  key)
37 {
38 objects.remove(key) ;
39 }
40
41 public synchronized void put(Object key, Object obj)
42 {
43 if ( objects.size() >= size )
44 expel(1) ;
45
46 policy.newItem(key, obj) ;
47 objects.put(key, obj) ;
48 }
49
50 public synchronized Object get(Object key)
51 {
52 log.trace("get("+key+")") ;
53 Object obj = objects.get(key) ;
54 if ( obj == null )
55 {
56 if ( objects.size() >= size )
57 expel(1) ;
58
59 obj = factory.create(key) ;
60 if ( obj == null )
61 log.warn("factory.create("+key+") returned null") ;
62
63 put(key, obj) ;
64 }
65 policy.update(key) ;
66 return obj ;
67 }
68
69 private void expel(int count)
70 {
71 Object [] keys = policy.expel(count) ;
72 for ( int i = 0 ; i < keys.length ; i++ )
73 {
74 Object obj = objects.remove(keys[i]) ;
75 factory.destroy(keys[i], obj) ;
76 }
77 }
78 }
79
80
81
107 |
Popular Tags |
Java API By Example, From Geeks To Geeks.