org.apache.mina.util

类 LazyInitializedCacheMap<K,V>

java.lang.Object

org.apache.mina.util.LazyInitializedCacheMap<K,V>

所有已实现的接口:

java.util.Map<K,V>

public class LazyInitializedCacheMap<K,V>
extends java.lang.Object
implements java.util.Map<K,V>

This map is specially useful when reads are much more frequent than writes and if the cost of instantiating the values is high like allocating an IoBuffer for example. Based on the final implementation of Memoizer written by Brian Goetz and Tim Peierls. This implementation will return an UnsupportedOperationException on each method that is not intended to be called by user code for performance reasons.

从以下版本开始:

MINA 2.0.0-M2

作者:

Apache MINA Project

嵌套类概要

嵌套类

限定符和类型	类和说明
class	LazyInitializedCacheMap.NoopInitializer This class provides a noop LazyInitializer meaning it will return the same object it received when instantiated.

从接口继承的嵌套类/接口 java.util.Map

java.util.Map.Entry<K,V>

构造器概要

构造器

构造器和说明
LazyInitializedCacheMap() Default constructor.
LazyInitializedCacheMap(java.util.concurrent.ConcurrentHashMap<K,LazyInitializer<V>> map) This constructor allows to provide a fine tuned ConcurrentHashMap to stick with each special case the user needs.

方法概要

方法

限定符和类型	方法和说明
void	clear()
boolean	containsKey(java.lang.Object key)
boolean	containsValue(java.lang.Object value) Throws UnsupportedOperationException as this method would imply performance drops.
java.util.Set<java.util.Map.Entry<K,V>>	entrySet() Throws UnsupportedOperationException as this method would imply performance drops.
V	get(java.lang.Object key)
java.util.Collection<LazyInitializer<V>>	getValues()
boolean	isEmpty()
java.util.Set<K>	keySet()
V	put(K key, V value)
void	putAll(java.util.Map<? extends K,? extends V> m)
V	putIfAbsent(K key, LazyInitializer<V> value) If the specified key is not already associated with a value, associate it with the given value.
V	remove(java.lang.Object key)
int	size()
java.util.Collection<V>	values() Throws UnsupportedOperationException as this method would imply performance drops.

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

从接口继承的方法 java.util.Map

equals, hashCode

构造器详细资料

LazyInitializedCacheMap

public LazyInitializedCacheMap()

Default constructor. Uses the default parameters to initialize its internal ConcurrentHashMap.

LazyInitializedCacheMap

public LazyInitializedCacheMap(java.util.concurrent.ConcurrentHashMap<K,LazyInitializer<V>> map)

This constructor allows to provide a fine tuned ConcurrentHashMap to stick with each special case the user needs.

参数:

map - The map to use as a cache

方法详细资料

get

public V get(java.lang.Object key)

指定者:

get 在接口中 java.util.Map<K,V>

remove

public V remove(java.lang.Object key)

指定者:

remove 在接口中 java.util.Map<K,V>

putIfAbsent

public V putIfAbsent(K key,
            LazyInitializer<V> value)

If the specified key is not already associated with a value, associate it with the given value. This is equivalent to

   if (!map.containsKey(key))
       return map.put(key, value);
   else
       return map.get(key);

except that the action is performed atomically.

参数:

key - key with which the specified value is to be associated

value - a lazy initialized value object.

返回:

the previous value associated with the specified key, or null if there was no mapping for the key

put

public V put(K key,
    V value)

指定者:

put 在接口中 java.util.Map<K,V>

containsValue

public boolean containsValue(java.lang.Object value)

Throws UnsupportedOperationException as this method would imply performance drops.

指定者:

containsValue 在接口中 java.util.Map<K,V>

values

public java.util.Collection<V> values()

Throws UnsupportedOperationException as this method would imply performance drops.

指定者:

values 在接口中 java.util.Map<K,V>

entrySet

public java.util.Set<java.util.Map.Entry<K,V>> entrySet()

Throws UnsupportedOperationException as this method would imply performance drops.

指定者:

entrySet 在接口中 java.util.Map<K,V>

putAll

public void putAll(java.util.Map<? extends K,? extends V> m)

指定者:

putAll 在接口中 java.util.Map<K,V>

getValues

public java.util.Collection<LazyInitializer<V>> getValues()

返回:

return the values from the cache

clear

public void clear()

指定者:

clear 在接口中 java.util.Map<K,V>

containsKey

public boolean containsKey(java.lang.Object key)

指定者:

containsKey 在接口中 java.util.Map<K,V>

isEmpty

public boolean isEmpty()

指定者:

isEmpty 在接口中 java.util.Map<K,V>

keySet

public java.util.Set<K> keySet()

指定者:

keySet 在接口中 java.util.Map<K,V>

size

public int size()

指定者:

size 在接口中 java.util.Map<K,V>