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1
52
53 package com.go.teaservlet.util;
54
55 import java.util.*;
56 import java.lang.ref.WeakReference  ;
57 import com.go.trove.util.IdentityMap;
58
59
89 public class ObjectIdentifier {
90 private static ObjectIdentifier cObjectIdentifer = new ObjectIdentifier();
91
92
95 public static String identify(Object obj) {
96 return cObjectIdentifer.getIdentifer(obj);
97 }
98
99
106 public static Object retrieve(String identifier) {
107 return cObjectIdentifer.getObject(identifier);
108 }
109
110 private Map mIdentifiers;
112
113 private Map mObjects;
115
116 private Random mRandom;
117
118 private ObjectIdentifier() {
119 mIdentifiers = new IdentityMap();
120 mObjects = new WeakHashMap();
121 mRandom = new Random();
122 }
123
124 private synchronized String getIdentifer(Object obj) {
125 String id = (String )mIdentifiers.get(obj);
126
127 if (id == null) {
128 do {
129 id = Long.toString(mRandom.nextLong() & Long.MAX_VALUE, 36);
130 } while (mObjects.containsKey(id));
131
132 mIdentifiers.put(obj, id);
133 mObjects.put(id, new WeakReference (obj));
134 }
135
136 return id;
137 }
138
139 private synchronized Object getObject(String identifier) {
140 WeakReference ref = (WeakReference )mObjects.get(identifier);
141 return (ref == null) ? null : ref.get();
142 }
143 }
144 |
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