com.github.houbb.cache.api

接口 ICacheMap<K,V>

类型参数:

K - 键

V - 值

所有已知子接口:

ICache<K,V>

public interface ICacheMap<K,V>

避免 jdk 的变化，导致接口的不稳定 简化 map 接口，去掉无用的实现

从以下版本开始:

1.0.0

方法概要

限定符和类型	方法和说明
boolean	containsKey(K key) Returns true if this map contains a mapping for the specified key.
V	get(K 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.
Set<K>	keySet() Returns a Set view of the keys contained in this map.
V	put(K key, V value) Associates the specified value with the specified key in this map (optional operation).
V	remove(K key) Removes the mapping for a key from this map if it is present (optional operation).
int	size() Returns the number of key-value mappings in this map.

方法详细资料

size

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.

返回:

the number of key-value mappings in this map

isEmpty

boolean isEmpty()

Returns true if this map contains no key-value mappings.

返回:

true if this map contains no key-value mappings

containsKey

boolean containsKey(K key)

Returns true if this map contains a mapping for the specified key. More formally, returns true if and only if this map contains a mapping for a key k such that (key==null ? k==null : key.equals(k)). (There can be at most one such mapping.)

参数:

key - key whose presence in this map is to be tested

返回:

true if this map contains a mapping for the specified key

抛出:

ClassCastException - if the key is of an inappropriate type for this map (optional)

NullPointerException - if the specified key is null and this map does not permit null keys (optional)

get

V get(K 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==null ? k==null : key.equals(k)), then this method returns v; otherwise it returns null. (There can be at most one such mapping.)

If this map permits null values, then a return value of null does not necessarily indicate that the map contains no mapping for the key; it's also possible that the map explicitly maps the key to null. The containsKey operation may be used to distinguish these two cases.

参数:

key - the key whose associated value is to be returned

返回:

the value to which the specified key is mapped, or null if this map contains no mapping for the key

抛出:

ClassCastException - if the key is of an inappropriate type for this map (optional)

NullPointerException - if the specified key is null and this map does not permit null keys (optional)

put

V put(K key,
      V value)

Associates the specified value with the specified key in this map (optional operation). If the map previously contained a mapping for the key, the old value is replaced by the specified value. (A map m is said to contain a mapping for a key k if and only if m.containsKey(k) would return true.)

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. (A null return can also indicate that the map previously associated null with key, if the implementation supports null values.)

抛出:

UnsupportedOperationException - if the put operation is not supported by this map

ClassCastException - if the class of the specified key or value prevents it from being stored in this map

NullPointerException - if the specified key or value is null and this map does not permit null keys or values

IllegalArgumentException - if some property of the specified key or value prevents it from being stored in this map

remove

V remove(K key)

Removes the mapping for a key from this map if it is present (optional operation). More formally, if this map contains a mapping from key k to value v such that (key==null ? k==null : key.equals(k)), that mapping is removed. (The map can contain at most one such mapping.)

Returns the value to which this map previously associated the key, or null if the map contained no mapping for the key.

If this map permits null values, then a return value of null does not necessarily indicate that the map contained no mapping for the key; it's also possible that the map explicitly mapped the key to null.

The map will not contain a mapping for the specified key once the call returns.

参数:

key - key whose mapping is to be removed from the map

返回:

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

抛出:

UnsupportedOperationException - if the remove operation is not supported by this map

ClassCastException - if the key is of an inappropriate type for this map (optional)

NullPointerException - if the specified key is null and this map does not permit null keys (optional)

keySet

Set<K> keySet()

Returns a Set view of the keys contained in this map. The set is backed by the map, so changes to the map are reflected in the set, and vice-versa. If the map is modified while an iteration over the set is in progress (except through the iterator's own remove operation), the results of the iteration are undefined. The set supports element removal, which removes the corresponding mapping from the map, via the Iterator.remove, Set.remove, removeAll, retainAll, and clear operations. It does not support the add or addAll operations.

返回:

a set view of the keys contained in this map