cn.trinea.android.common.service.impl

Class SimpleCache<K,V>

java.lang.Object

cn.trinea.android.common.service.impl.SimpleCache<K,V>

All Implemented Interfaces:

Cache<K,V>, java.io.Serializable

Direct Known Subclasses:

PreloadDataCache

public class SimpleCache<K,V>
extends java.lang.Object
implements Cache<K,V>, java.io.Serializable

Simple Cache

Usage
• Use one of constructors below to construct cache
• setCacheFullRemoveType(CacheFullRemoveType) set remove type when cache is full
• setValidTime(long) set valid time of elements in cache, in mills
• put(Object, CacheObject) or put(Object, Object) put element
• get(Object) get element
• loadCache(String) restore cache from file
• saveCache(String, SimpleCache) save cache to file

Constructor
• SimpleCache()
• SimpleCache(int)
• loadCache(String) restore cache from file

About hit and miss of the cache
• getHitRate() get hit rate of the cache
• getHitCount() get hit count of the cache
• getMissCount() get miss count of the cache

About size of cache
• getMaxSize() get the maximum capacity of the cache
• getSize() get the number of elements in the cache valid

Other interfaces same to Map

Author:

Trinea 2011-12-23

See Also:

Serialized Form

Field Summary

Fields

Modifier and Type	Field and Description
static int	DEFAULT_MAX_SIZE default maximum capacity of the cache

Constructor Summary

Constructors

Constructor and Description
SimpleCache() Maximum size of the cache is DEFAULT_MAX_SIZE Elements of the cache will not invalid, can set by setValidTime(long) Remove type is RemoveTypeEnterTimeFirst when cache is full
SimpleCache(int maxSize) Elements of the cache will not invalid, can set by setValidTime(long) Remove type is RemoveTypeEnterTimeFirst when cache is full

Method Summary

Methods

Modifier and Type	Method and Description
void	clear() Removes all elements from this Map, leaving it empty.
boolean	containsKey(K key) whether this cache contains the specified key.
java.util.Set<java.util.Map.Entry<K,CacheObject<V>>>	entrySet() key value set
CacheObject<V>	get(K key) get element
CacheFullRemoveType<V>	getCacheFullRemoveType() get remove type when cache is full
long	getHitCount() get hit count
double	getHitRate() get hit rate
int	getMaxSize() get the maximum capacity of the cache
long	getMissCount() get miss count
int	getSize() get the number of elements in the cache valid
long	getValidTime() get valid time of elements in cache, in mills.
java.util.Set<K>	keySet() key set
static <K,V> SimpleCache<K,V>	loadCache(java.lang.String filePath) restore cache from file
CacheObject<V>	put(K key, CacheObject<V> value) put element, key and value both not allowed to be null
CacheObject<V>	put(K key, V value) put element, key not allowed to be null
void	putAll(Cache<K,V> cache2) pull all elements of cache2 to this
CacheObject<V>	remove(K key) remove the specified key from cache, key not allowed to be null
static <K,V> void	saveCache(java.lang.String filePath, SimpleCache<K,V> cache) save cache to file, the data of CacheObject should can be serializabled
void	setCacheFullRemoveType(CacheFullRemoveType<V> cacheFullRemoveType) set remove type when cache is full
void	setValidTime(long validTime) set valid time of elements in cache, in mills
java.util.Collection<CacheObject<V>>	values() value set

Methods inherited from class java.lang.Object

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

Field Detail

DEFAULT_MAX_SIZE

public static final int DEFAULT_MAX_SIZE

default maximum capacity of the cache

See Also:

Constant Field Values

Constructor Detail

SimpleCache

public SimpleCache()

• Maximum size of the cache is DEFAULT_MAX_SIZE
• Elements of the cache will not invalid, can set by setValidTime(long)
• Remove type is RemoveTypeEnterTimeFirst when cache is full

SimpleCache

public SimpleCache(int maxSize)

• Elements of the cache will not invalid, can set by setValidTime(long)
• Remove type is RemoveTypeEnterTimeFirst when cache is full

Parameters:

maxSize - maximum size of the cache

Method Detail

getMaxSize

public int getMaxSize()

get the maximum capacity of the cache

Returns:

getValidTime

public long getValidTime()

get valid time of elements in cache, in mills. It means not invalid if less than 0

Returns:

setValidTime

public void setValidTime(long validTime)

set valid time of elements in cache, in mills

Parameters:

validTime - valid time of elements in cache, in mills. If less than 0, it will be set to -1 and means not invalid. Rule of invalid see isExpired(CacheObject)

getCacheFullRemoveType

public CacheFullRemoveType<V> getCacheFullRemoveType()

get remove type when cache is full

Returns:

setCacheFullRemoveType

public void setCacheFullRemoveType(CacheFullRemoveType<V> cacheFullRemoveType)

set remove type when cache is full

Parameters:

cacheFullRemoveType - the cacheFullRemoveType to set

getSize

public int getSize()

get the number of elements in the cache valid

Specified by:

getSize in interface Cache<K,V>

Returns:

get

public CacheObject<V> get(K key)

get element

Specified by:

get in interface Cache<K,V>

Parameters:

key -

Returns:

element if this cache contains the specified key and the element is valid, null otherwise.

put

public CacheObject<V> put(K key,
                 V value)

put element, key not allowed to be null

Specified by:

put in interface Cache<K,V>

Parameters:

key - key

value - data of CacheObject

Returns:

return null if cache is full and cannot remove one, else return the value be putted

See Also:

put(Object, CacheObject)

put

public CacheObject<V> put(K key,
                 CacheObject<V> value)

put element, key and value both not allowed to be null

Specified by:

put in interface Cache<K,V>

Parameters:

key -

value -

Returns:

return null if cache is full and cannot remove one, else return the value be putted

putAll

public void putAll(Cache<K,V> cache2)

pull all elements of cache2 to this

Specified by:

putAll in interface Cache<K,V>

Parameters:

cache2 -

containsKey

public boolean containsKey(K key)

whether this cache contains the specified key.

Specified by:

containsKey in interface Cache<K,V>

Parameters:

key -

Returns:

true if this cache contains the specified key and the element is valid, false otherwise.

remove

public CacheObject<V> remove(K key)

remove the specified key from cache, key not allowed to be null

Specified by:

remove in interface Cache<K,V>

Parameters:

key -

Returns:

the value of the removed or null if no mapping for the specified key was found.

clear

public void clear()

Removes all elements from this Map, leaving it empty.

Specified by:

clear in interface Cache<K,V>

See Also:

Map.clear()

getHitCount

public long getHitCount()

get hit count

getMissCount

public long getMissCount()

get miss count

getHitRate

public double getHitRate()

get hit rate

Specified by:

getHitRate in interface Cache<K,V>

Returns:

keySet

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

Description copied from interface: Cache

key set

Specified by:

keySet in interface Cache<K,V>

Returns:

a set of the keys.

See Also:

Map.keySet()

entrySet

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

Description copied from interface: Cache

key value set

Specified by:

entrySet in interface Cache<K,V>

Returns:

a set of the mappings

See Also:

Map.entrySet()

values

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

Description copied from interface: Cache

value set

Specified by:

values in interface Cache<K,V>

Returns:

a collection of the values contained in this cache.

See Also:

Map.values()

loadCache

public static <K,V> SimpleCache<K,V> loadCache(java.lang.String filePath)

restore cache from file

Parameters:

filePath -

Returns:

saveCache

public static <K,V> void saveCache(java.lang.String filePath,
                   SimpleCache<K,V> cache)

save cache to file, the data of CacheObject should can be serializabled

Type Parameters:

K -

V -

Parameters:

filePath -

cache -