DefaultCache (onecode-common-client 1.1.1 API)

java.lang.Object
- com.ds.common.cache.DefaultCache<K,V>

所有已实现的接口:

Cache<K,V>, Map<K,V>
```
public class DefaultCache<K,V>
extends Object
implements Cache<K,V>
```
Title: 常用代码打包

Description: Default, non-distributed implementation of the Cache interface. The algorithm for cache is as follows: a HashMap is maintained for fast object lookup. Two linked lists are maintained: one keeps objects in the order they are accessed from cache, the other keeps objects in the order they were originally added to cache. When objects are added to cache, they are first wrapped by a CacheObject which maintains the following pieces of information:
- The size of the object (in bytes).
- A pointer to the node in the linked list that maintains accessed order for the object. Keeping a reference to the node lets us avoid linear scans of the linked list.
- A pointer to the node in the linked list that maintains the age of the object in cache. Keeping a reference to the node lets us avoid linear scans of the linked list.
To get an object from cache, a hash lookup is performed to get a reference to the CacheObject that wraps the real object we are looking for. The object is subsequently moved to the front of the accessed linked list and any necessary cache cleanups are performed. Cache deletion and expiration is performed as needed.

Copyright: Copyright (c) 2006

Company: www.justdos.net
版本:

1.0

作者:

wenzhang li

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

字段概要

字段
限定符和类型	字段和说明
`protected LinkedList`	`ageList` Linked list to maintain time that cache objects were initially added to the cache, most recently added to oldest added.
`protected long`	`cacheHits` Maintain the number of cache hits and misses.
`protected long`	`cacheMisses` Maintain the number of cache hits and misses.
`protected int`	`cacheSize` Maintains the current size of the cache in bytes.
`protected boolean`	`isStopPutWhenFull`
`protected LinkedList`	`lastAccessedList` Linked list to maintain order that cache objects are accessed in, most used to least used.
`protected Map`	`map` The map the keys and values are stored in.
`protected int`	`maxCacheSize` Maximum size in bytes that the cache can grow to.
`protected long`	`maxLifetime` Maximum length of time objects can exist in cache before expiring.
`protected String`	`name` The name of the cache.

构造器概要

构造器
限定符	构造器和说明
`protected`	`DefaultCache(String name, int maxSize, long maxLifetime)` Create a new cache and specify the maximum size of for the cache in bytes, and the maximum lifetime of objects.

方法概要

所有方法实例方法具体方法
限定符和类型	方法和说明
`protected int`	`calculateSize(Object object)` Returns the size of an object in bytes.
`void`	`clear()` Removes all cached datas from this cache (optional operation).
`boolean`	`containsKey(Object key)`
`boolean`	`containsValue(Object value)`
`protected void`	`cullCache()` Removes objects from cache if the cache is too full.
`protected void`	`deleteExpiredEntries()` Clears all entries out of cache where the entries are older than the maximum defined age.
`Set`	`entrySet()`
`V`	`get(Object key)`
`long`	`getCacheHits()` Returns the number of cache hits.
`long`	`getCacheMisses()` Returns the number of cache misses.
`int`	`getCacheSize()` Returns the size of the cache contents in bytes.
`int`	`getMaxCacheSize()` Returns the maximum size of the cache in bytes.
`long`	`getMaxLifetime()` Returns the maximum number of milleseconds that any object can live in cache.
`K`	`getName()` Implementation methods of Cache interface
`boolean`	`isEmpty()`
`Set`	`keySet()`
`V`	`put(K key, V value)`
`void`	`putAll(Map<? extends K,? extends V> m)`
`V`	`remove(Object key)`
`void`	`setMaxCacheSize(int maxCacheSize)` Sets the maximum size of the cache in bytes.
`void`	`setMaxLifetime(long maxLifetime)` Sets the maximum number of milleseconds that any object can live in cache.
`void`	`setStopPutWhenFull(boolean flag)` set the flag whether stop putting into cache when it was full or not.
`int`	`size()`
`Collection`	`values()`

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
compute, computeIfAbsent, computeIfPresent, equals, forEach, getOrDefault, hashCode, merge, putIfAbsent, remove, replace, replace, replaceAll

- 字段详细资料
  - map
```
protected Map map
```
    The map the keys and values are stored in.
  - lastAccessedList
```
protected LinkedList lastAccessedList
```
    Linked list to maintain order that cache objects are accessed in, most used to least used.
  - ageList
```
protected LinkedList ageList
```
    Linked list to maintain time that cache objects were initially added to the cache, most recently added to oldest added.
  - maxCacheSize
```
protected int maxCacheSize
```
    Maximum size in bytes that the cache can grow to.
  - cacheSize
```
protected int cacheSize
```
    Maintains the current size of the cache in bytes.
  - maxLifetime
```
protected long maxLifetime
```
    Maximum length of time objects can exist in cache before expiring.
  - cacheHits
```
protected long cacheHits
```
    Maintain the number of cache hits and misses. A cache hit occurs every time the get method is called and the cache contains the requested object. A cache miss represents the opposite occurence.
    
    Keeping track of cache hits and misses lets one measure how efficient the cache is; the higher the percentage of hits, the more efficient.
  - cacheMisses
```
protected long cacheMisses
```
    Maintain the number of cache hits and misses. A cache hit occurs every time the get method is called and the cache contains the requested object. A cache miss represents the opposite occurence.
    
    Keeping track of cache hits and misses lets one measure how efficient the cache is; the higher the percentage of hits, the more efficient.
  - name
```
protected String name
```
    The name of the cache.
  - isStopPutWhenFull
```
protected boolean isStopPutWhenFull
```
- 构造器详细资料
  - DefaultCache
```
protected DefaultCache(String name,
                       int maxSize,
                       long maxLifetime)
```
    Create a new cache and specify the maximum size of for the cache in bytes, and the maximum lifetime of objects.
    
    参数:
    
    name - a name for the cache.
    
    maxSize - the maximum size of the cache in bytes. -1 means the cache has no max size.
    
    maxLifetime - the maximum amount of time objects can exist in cache before being deleted. -1 means objects never expire.
- 方法详细资料
  - put
```
public V put(K key,
             V value)
```
    指定者:
    
    put 在接口中 Map<K,V>
  - get
```
public V get(Object key)
```
    指定者:
    
    get 在接口中 Map<K,V>
  - remove
```
public V remove(Object key)
```
    指定者:
    
    remove 在接口中 Map<K,V>
  - clear
```
public void clear()
```
    从接口复制的说明: Cache
    
    Removes all cached datas from this cache (optional operation).
    
    指定者:
    
    clear 在接口中 Cache<K,V>
    
    指定者:
    
    clear 在接口中 Map<K,V>
  - size
```
public int size()
```
    指定者:
    
    size 在接口中 Map<K,V>
  - isEmpty
```
public boolean isEmpty()
```
    指定者:
    
    isEmpty 在接口中 Map<K,V>
  - values
```
public Collection values()
```
    指定者:
    
    values 在接口中 Map<K,V>
  - containsKey
```
public boolean containsKey(Object key)
```
    指定者:
    
    containsKey 在接口中 Map<K,V>
  - putAll
```
public void putAll(Map<? extends K,? extends V> m)
```
    指定者:
    
    putAll 在接口中 Map<K,V>
  - containsValue
```
public boolean containsValue(Object value)
```
    指定者:
    
    containsValue 在接口中 Map<K,V>
  - entrySet
```
public Set entrySet()
```
    指定者:
    
    entrySet 在接口中 Map<K,V>
  - keySet
```
public Set keySet()
```
    指定者:
    
    keySet 在接口中 Map<K,V>
  - getName
```
public K getName()
```
    Implementation methods of Cache interface
    
    指定者:
    
    getName 在接口中 Cache<K,V>
    
    返回:
    
    the name of the cache.
  - getCacheHits
```
public long getCacheHits()
```
    从接口复制的说明: Cache
    
    Returns the number of cache hits. A cache hit occurs every time the get method is called and the cache contains the requested object.
    Keeping track of cache hits and misses lets one measure how efficient the cache is; the higher the percentage of hits, the more efficient.
    
    指定者:
    
    getCacheHits 在接口中 Cache<K,V>
    
    返回:
    
    the number of cache hits.
  - getCacheMisses
```
public long getCacheMisses()
```
    从接口复制的说明: Cache
    
    Returns the number of cache misses. A cache miss occurs every time the get method is called and the cache does not contain the requested object.
    Keeping track of cache hits and misses lets one measure how efficient the cache is; the higher the percentage of hits, the more efficient.
    
    指定者:
    
    getCacheMisses 在接口中 Cache<K,V>
    
    返回:
    
    the number of cache hits.
  - getCacheSize
```
public int getCacheSize()
```
    从接口复制的说明: Cache
    
    Returns the size of the cache contents in bytes. This value is only a rough approximation, so cache users should expect that actual VM memory used by the cache could be significantly higher than the value reported by this method.
    
    指定者:
    
    getCacheSize 在接口中 Cache<K,V>
    
    返回:
    
    the size of the cache contents in bytes.
  - getMaxCacheSize
```
public int getMaxCacheSize()
```
    从接口复制的说明: Cache
    
    Returns the maximum size of the cache in bytes. If the cache grows larger than the max size, the least frequently used items will be removed. If the max cache size is set to -1, there is no size limit.
    
    指定者:
    
    getMaxCacheSize 在接口中 Cache<K,V>
    
    返回:
    
    the maximum size of the cache in bytes.
  - setMaxCacheSize
```
public void setMaxCacheSize(int maxCacheSize)
```
    从接口复制的说明: Cache
    
    Sets the maximum size of the cache in bytes. If the cache grows larger than the max size, the least frequently used items will be removed. If the max cache size is set to -1, there is no size limit.
    
    指定者:
    
    setMaxCacheSize 在接口中 Cache<K,V>
    
    参数:
    
    maxCacheSize - the maximum size of the cache in bytes.
  - getMaxLifetime
```
public long getMaxLifetime()
```
    从接口复制的说明: Cache
    
    Returns the maximum number of milleseconds that any object can live in cache. Once the specified number of milleseconds passes, the object will be automatically expried from cache. If the max lifetime is set to -1, then objects never expire.
    
    指定者:
    
    getMaxLifetime 在接口中 Cache<K,V>
    
    返回:
    
    the maximum number of milleseconds before objects are expired.
  - setMaxLifetime
```
public void setMaxLifetime(long maxLifetime)
```
    从接口复制的说明: Cache
    
    Sets the maximum number of milleseconds that any object can live in cache. Once the specified number of milleseconds passes, the object will be automatically expried from cache. If the max lifetime is set to -1, then objects never expire.
    
    指定者:
    
    setMaxLifetime 在接口中 Cache<K,V>
    
    参数:
    
    maxLifetime - the maximum number of milleseconds before objects are expired.
  - calculateSize
```
protected int calculateSize(Object object)
```
    Returns the size of an object in bytes. Determining size by serialization is only used as a last resort.
    
    返回:
    
    the size of an object in bytes.
  - deleteExpiredEntries
```
protected void deleteExpiredEntries()
```
    Clears all entries out of cache where the entries are older than the maximum defined age.
  - cullCache
```
protected void cullCache()
```
    Removes objects from cache if the cache is too full. "Too full" is defined as within 3% of the maximum cache size. Whenever the cache is is too big, the least frequently used elements are deleted until the cache is at least 10% empty.
  - setStopPutWhenFull
```
public void setStopPutWhenFull(boolean flag)
```
    从接口复制的说明: Cache
    
    set the flag whether stop putting into cache when it was full or not.
    
    指定者:
    
    setStopPutWhenFull 在接口中 Cache<K,V>

类 DefaultCache<K,V>

嵌套类概要

从接口继承的嵌套类/接口 java.util.Map

字段概要

构造器概要

方法概要

从类继承的方法 java.lang.Object

从接口继承的方法 java.util.Map

字段详细资料

map

lastAccessedList

ageList

maxCacheSize

cacheSize

maxLifetime

cacheHits

cacheMisses

name

isStopPutWhenFull

构造器详细资料

DefaultCache

方法详细资料

put

get

remove

clear

size

isEmpty

values

containsKey

putAll

containsValue

entrySet

keySet

getName

getCacheHits

getCacheMisses

getCacheSize

getMaxCacheSize

setMaxCacheSize

getMaxLifetime

setMaxLifetime

calculateSize

deleteExpiredEntries

cullCache

setStopPutWhenFull