ConcurrentIdentityHashMap (druid 0.2.23 API)

java.lang.Object
- java.util.AbstractMap<K,V>
- - com.alibaba.druid.util.ConcurrentIdentityHashMap<K,V>

类型参数:
K - the type of keys maintained by this map
V - the type of mapped values

所有已实现的接口:

ConcurrentMap<K,V>, Map<K,V>
```
public class ConcurrentIdentityHashMap<K,V>
extends AbstractMap<K,V>
implements ConcurrentMap<K,V>
```
An alternative identity-comparing ConcurrentMap which is similar to ConcurrentHashMap.

版本:

$Rev: 2217 $, $Date: 2010-03-16 18:39:56 +0900 (Tue, 16 Mar 2010) $

作者:

The Netty Project, Doug Lea, Jason T. Greene, Trustin Lee

嵌套类概要
- 从类继承的嵌套类/接口 java.util.AbstractMap
  AbstractMap.SimpleImmutableEntry<K,V>
- 从接口继承的嵌套类/接口 java.util.Map
  Map.Entry<K,V>

构造器概要

构造器
构造器和说明
`ConcurrentIdentityHashMap()` Creates a new, empty map with a default initial capacity (16), reference types (weak keys, strong values), default load factor (0.75) and concurrencyLevel (16).
`ConcurrentIdentityHashMap(int initialCapacity)` Creates a new, empty map with the specified initial capacity, and with default reference types (weak keys, strong values), load factor (0.75) and concurrencyLevel (16).
`ConcurrentIdentityHashMap(int initialCapacity, float loadFactor, int concurrencyLevel)` Creates a new, empty map with the specified initial capacity, load factor and concurrency level.

方法概要

方法
限定符和类型	方法和说明
`void`	`clear()` Removes all of the mappings from this map.
`boolean`	`contains(Object value)`
`boolean`	`containsKey(Object key)` Tests if the specified object is a key in this table.
`boolean`	`containsValue(Object value)` Returns `true` if this map maps one or more keys to the specified value.
`Enumeration<V>`	`elements()` Returns an enumeration of the values in this table.
`Set<Map.Entry<K,V>>`	`entrySet()`
`V`	`get(Object key)` Returns the value to which the specified key is mapped, or `null` if this map contains no mapping for the key.
`boolean`	`isEmpty()` Returns `true` if this map contains no key-value mappings.
`Enumeration<K>`	`keys()` Returns an enumeration of the keys in this table.
`Set<K>`	`keySet()`
`V`	`put(K key, V value)` Maps the specified key to the specified value in this table.
`V`	`putIfAbsent(K key, V value)`
`V`	`remove(Object key)` Removes the key (and its corresponding value) from this map.
`boolean`	`remove(Object key, Object value)`
`V`	`replace(K key, V value)`
`boolean`	`replace(K key, V oldValue, V newValue)`
`int`	`size()` Returns the number of key-value mappings in this map.
`Collection<V>`	`values()`

从类继承的方法 java.util.AbstractMap
equals, hashCode, putAll, toString

从类继承的方法 java.lang.Object
getClass, notify, notifyAll, wait, wait, wait

从接口继承的方法 java.util.Map
equals, hashCode, putAll

- 构造器详细资料
  - ConcurrentIdentityHashMap
```
public ConcurrentIdentityHashMap(int initialCapacity,
                         float loadFactor,
                         int concurrencyLevel)
```
    Creates a new, empty map with the specified initial capacity, load factor and concurrency level.
    
    参数:
    initialCapacity - the initial capacity. The implementation performs internal sizing to accommodate this many elements.
    loadFactor - the load factor threshold, used to control resizing. Resizing may be performed when the average number of elements per bin exceeds this threshold.
    concurrencyLevel - the estimated number of concurrently updating threads. The implementation performs internal sizing to try to accommodate this many threads.
    
    抛出:
    
    IllegalArgumentException - if the initial capacity is negative or the load factor or concurrencyLevel are nonpositive.
  - ConcurrentIdentityHashMap
```
public ConcurrentIdentityHashMap(int initialCapacity)
```
    Creates a new, empty map with the specified initial capacity, and with default reference types (weak keys, strong values), load factor (0.75) and concurrencyLevel (16).
    
    参数:
    initialCapacity - the initial capacity. The implementation performs internal sizing to accommodate this many elements.
    
    抛出:
    
    IllegalArgumentException - if the initial capacity of elements is negative.
  - ConcurrentIdentityHashMap
```
public ConcurrentIdentityHashMap()
```
    Creates a new, empty map with a default initial capacity (16), reference types (weak keys, strong values), default load factor (0.75) and concurrencyLevel (16).
- 方法详细资料
  - isEmpty
```
public boolean isEmpty()
```
    Returns true if this map contains no key-value mappings.
    
    指定者:
    
    isEmpty 在接口中 Map<K,V>
    
    覆盖:
    
    isEmpty 在类中 AbstractMap<K,V>
    
    返回:
    true if this map contains no key-value mappings
  - size
```
public int size()
```
    Returns the number of key-value mappings in this map. If the map contains more than Integer.MAX_VALUE elements, returns Integer.MAX_VALUE.
    
    指定者:
    
    size 在接口中 Map<K,V>
    
    覆盖:
    
    size 在类中 AbstractMap<K,V>
    
    返回:
    the number of key-value mappings in this map
  - get
```
public V get(Object key)
```
    Returns the value to which the specified key is mapped, or null if this map contains no mapping for the key.
    More formally, if this map contains a mapping from a key k to a value v such that key.equals(k), then this method returns v; otherwise it returns null. (There can be at most one such mapping.)
    
    指定者:
    
    get 在接口中 Map<K,V>
    
    覆盖:
    
    get 在类中 AbstractMap<K,V>
    
    抛出:
    
    NullPointerException - if the specified key is null
  - containsKey
```
public boolean containsKey(Object key)
```
    Tests if the specified object is a key in this table.
    
    指定者:
    
    containsKey 在接口中 Map<K,V>
    
    覆盖:
    
    containsKey 在类中 AbstractMap<K,V>
    
    参数:
    key - possible key
    
    返回:
    true if and only if the specified object is a key in this table, as determined by the equals method; false otherwise.
    
    抛出:
    
    NullPointerException - if the specified key is null
  - containsValue
```
public boolean containsValue(Object value)
```
    Returns true if this map maps one or more keys to the specified value. Note: This method requires a full internal traversal of the hash table, and so is much slower than method containsKey.
    
    指定者:
    
    containsValue 在接口中 Map<K,V>
    
    覆盖:
    
    containsValue 在类中 AbstractMap<K,V>
    
    参数:
    value - value whose presence in this map is to be tested
    
    返回:
    true if this map maps one or more keys to the specified value
    
    抛出:
    
    NullPointerException - if the specified value is null
  - contains
```
public boolean contains(Object value)
```
  - put
```
public V put(K key,
    V value)
```
    Maps the specified key to the specified value in this table. Neither the key nor the value can be null.
    The value can be retrieved by calling the get method with a key that is equal to the original key.
    
    指定者:
    
    put 在接口中 Map<K,V>
    
    覆盖:
    
    put 在类中 AbstractMap<K,V>
    
    参数:
    key - key with which the specified value is to be associated
    value - value to be associated with the specified key
    
    返回:
    the previous value associated with key, or null if there was no mapping for key
    
    抛出:
    
    NullPointerException - if the specified key or value is null
  - putIfAbsent
```
public V putIfAbsent(K key,
            V value)
```
    指定者:
    
    putIfAbsent 在接口中 ConcurrentMap<K,V>
    
    返回:
    the previous value associated with the specified key, or null if there was no mapping for the key
    
    抛出:
    
    NullPointerException - if the specified key or value is null
  - remove
```
public V remove(Object key)
```
    Removes the key (and its corresponding value) from this map. This method does nothing if the key is not in the map.
    
    指定者:
    
    remove 在接口中 Map<K,V>
    
    覆盖:
    
    remove 在类中 AbstractMap<K,V>
    
    参数:
    key - the key that needs to be removed
    
    返回:
    the previous value associated with key, or null if there was no mapping for key
    
    抛出:
    
    NullPointerException - if the specified key is null
  - remove
```
public boolean remove(Object key,
             Object value)
```
    指定者:
    
    remove 在接口中 ConcurrentMap<K,V>
    
    抛出:
    
    NullPointerException - if the specified key is null
  - replace
```
public boolean replace(K key,
              V oldValue,
              V newValue)
```
    指定者:
    
    replace 在接口中 ConcurrentMap<K,V>
    
    抛出:
    
    NullPointerException - if any of the arguments are null
  - replace
```
public V replace(K key,
        V value)
```
    指定者:
    
    replace 在接口中 ConcurrentMap<K,V>
    
    返回:
    the previous value associated with the specified key, or null if there was no mapping for the key
    
    抛出:
    
    NullPointerException - if the specified key or value is null
  - clear
```
public void clear()
```
    Removes all of the mappings from this map.
    
    指定者:
    
    clear 在接口中 Map<K,V>
    
    覆盖:
    
    clear 在类中 AbstractMap<K,V>
  - keySet
```
public Set<K> keySet()
```
    指定者:
    
    keySet 在接口中 Map<K,V>
    
    覆盖:
    
    keySet 在类中 AbstractMap<K,V>
  - values
```
public Collection<V> values()
```
    指定者:
    
    values 在接口中 Map<K,V>
    
    覆盖:
    
    values 在类中 AbstractMap<K,V>
  - entrySet
```
public Set<Map.Entry<K,V>> entrySet()
```
    指定者:
    
    entrySet 在接口中 Map<K,V>
    
    指定者:
    
    entrySet 在类中 AbstractMap<K,V>
  - keys
```
public Enumeration<K> keys()
```
    Returns an enumeration of the keys in this table.
    
    返回:
    an enumeration of the keys in this table
    另请参阅:
    keySet()
  - elements
```
public Enumeration<V> elements()
```
    Returns an enumeration of the values in this table.
    
    返回:
    an enumeration of the values in this table
    另请参阅:
    values()

类 ConcurrentIdentityHashMap<K,V>

嵌套类概要

从类继承的嵌套类/接口 java.util.AbstractMap

从接口继承的嵌套类/接口 java.util.Map

构造器概要

方法概要

从类继承的方法 java.util.AbstractMap

从类继承的方法 java.lang.Object

从接口继承的方法 java.util.Map

构造器详细资料

ConcurrentIdentityHashMap

ConcurrentIdentityHashMap

ConcurrentIdentityHashMap

方法详细资料

isEmpty

size

get

containsKey

containsValue

contains

put

putIfAbsent

remove

remove

replace

replace

clear

keySet

values

entrySet

keys

elements