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20 package org.apache.mina.util;
21
22 import java.util.Collection;
23 import java.util.Map;
24 import java.util.Set;
25 import java.util.concurrent.ConcurrentHashMap;
26 import java.util.concurrent.ConcurrentMap;
27
28 import org.apache.mina.core.buffer.IoBuffer;
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43 public class LazyInitializedCacheMap<K, V> implements Map<K, V> {
44 private ConcurrentMap<K, LazyInitializer<V>> cache;
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50 public class NoopInitializer extends LazyInitializer<V> {
51 private V value;
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53 public NoopInitializer(V value) {
54 this.value = value;
55 }
56
57 public V init() {
58 return value;
59 }
60 }
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66 public LazyInitializedCacheMap() {
67 this.cache = new ConcurrentHashMap<K, LazyInitializer<V>>();
68 }
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74 public LazyInitializedCacheMap(final ConcurrentHashMap<K, LazyInitializer<V>> map) {
75 this.cache = map;
76 }
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81 public V get(Object key) {
82 LazyInitializer<V> c = cache.get(key);
83 if (c != null) {
84 return c.get();
85 }
86
87 return null;
88 }
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93 public V remove(Object key) {
94 LazyInitializer<V> c = cache.remove(key);
95 if (c != null) {
96 return c.get();
97 }
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99 return null;
100 }
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119 public V putIfAbsent(K key, LazyInitializer<V> value) {
120 LazyInitializer<V> v = cache.get(key);
121 if (v == null) {
122 v = cache.putIfAbsent(key, value);
123 if (v == null) {
124 return value.get();
125 }
126 }
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128 return v.get();
129 }
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134 public V put(K key, V value) {
135 LazyInitializer<V> c = cache.put(key, new NoopInitializer(value));
136 if (c != null) {
137 return c.get();
138 }
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140 return null;
141 }
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147 public boolean containsValue(Object value) {
148 throw new UnsupportedOperationException();
149 }
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155 public Collection<V> values() {
156 throw new UnsupportedOperationException();
157 }
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163 public Set<java.util.Map.Entry<K, V>> entrySet() {
164 throw new UnsupportedOperationException();
165 }
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170 public void putAll(Map<? extends K, ? extends V> m) {
171 for (Map.Entry<? extends K, ? extends V> e : m.entrySet()) {
172 cache.put(e.getKey(), new NoopInitializer(e.getValue()));
173 }
174 }
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179 public Collection<LazyInitializer<V>> getValues() {
180 return cache.values();
181 }
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186 public void clear() {
187 cache.clear();
188 }
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193 public boolean containsKey(Object key) {
194 return cache.containsKey(key);
195 }
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200 public boolean isEmpty() {
201 return cache.isEmpty();
202 }
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207 public Set<K> keySet() {
208 return cache.keySet();
209 }
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214 public int size() {
215 return cache.size();
216 }
217 }