org.zkoss.util

Class FastReadCache<K,V>

java.lang.Object

org.zkoss.util.FastReadCache<K,V>

All Implemented Interfaces:

Serializable, Cloneable, Cache<K,V>

public class FastReadCache<K,V>
extends Object
implements Cache<K,V>, Serializable, Cloneable

A CacheMap that the possibility to have cache hit is much more than not. It maintains a readonly cache (so no need to synchronize), and then clone and replace it if there is a miss. Thus, as time goes, most access can go directly to the readonly cache without any synchronization or cloning.

Thread safe.

Since:

6.0.0

Author:

tomyeh

See Also:

Serialized Form

Field Summary

Fields inherited from interface org.zkoss.util.Cache

DEFAULT_LIFETIME, DEFAULT_MAX_SIZE

Constructor Summary

Constructors

Constructor and Description
FastReadCache() Constructor.
FastReadCache(int maxSize, int lifetime) Constructor.
FastReadCache(int maxSize, int lifetime, short maxMissCount) Constructor.

Method Summary

Modifier and Type	Method and Description
void	clear() Clears all objects being cached.
boolean	containsKey(Object key) Returns whether the specified key is stored.
V	get(Object key) Returns the object of the specified key, or null if not found.
int	getLifetime() Returns the minimal lifetime, unit=milliseconds.
int	getMaxSize() Returns the maximal allowed size.
V	put(K key, V value) Stores an object to the cache.
V	remove(Object key) Removes an object from the cache.
void	setLifetime(int lifetime) Sets the minimal lifetime.
void	setMaxSize(int maxsize) Sets the maximal allowed size.

Methods inherited from class java.lang.Object

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

Constructor Detail

FastReadCache

public FastReadCache()

Constructor.

FastReadCache

public FastReadCache(int maxSize,
                     int lifetime)

Constructor.

FastReadCache

public FastReadCache(int maxSize,
                     int lifetime,
                     short maxMissCount)

Constructor.

Parameters:

maxMissCount - a short value from 0 to this for sync the read cache, default is 100.

Since:

6.5.2

Method Detail

containsKey

public boolean containsKey(Object key)

Description copied from interface: Cache

Returns whether the specified key is stored.

Specified by:

containsKey in interface Cache<K,V>

get

public V get(Object key)

Description copied from interface: Cache

Returns the object of the specified key, or null if not found.

Specified by:

get in interface Cache<K,V>

put

public V put(K key,
             V value)

Description copied from interface: Cache

Stores an object to the cache.

Specified by:

put in interface Cache<K,V>

Returns:

the previous value of the same, or null if no such value

remove

public V remove(Object key)

Description copied from interface: Cache

Removes an object from the cache.

Specified by:

remove in interface Cache<K,V>

Returns:

the object if found.

clear

public void clear()

Description copied from interface: Cache

Clears all objects being cached.

Specified by:

clear in interface Cache<K,V>

getLifetime

public int getLifetime()

Description copied from interface: Cache

Returns the minimal lifetime, unit=milliseconds. An mapping won't be removed by GC unless the minimal lifetime or the maximal allowed size exceeds.

Specified by:

getLifetime in interface Cache<K,V>

See Also:

Cache.getMaxSize()

setLifetime

public void setLifetime(int lifetime)

Description copied from interface: Cache

Sets the minimal lifetime. Default: Cache.DEFAULT_LIFETIME.

Specified by:

setLifetime in interface Cache<K,V>

Parameters:

lifetime - the lifetime, unit=milliseconds; if non-positive, they will be removed immediately.

See Also:

Cache.getLifetime()

getMaxSize

public int getMaxSize()

Description copied from interface: Cache

Returns the maximal allowed size. Default: Cache.DEFAULT_MAX_SIZE. An mapping won't be removed by GC unless the minimal lifetime or the maximal allowed size exceeds.

Specified by:

getMaxSize in interface Cache<K,V>

See Also:

Cache.getLifetime()

setMaxSize

public void setMaxSize(int maxsize)

Description copied from interface: Cache

Sets the maximal allowed size.

Specified by:

setMaxSize in interface Cache<K,V>

See Also:

Cache.getMaxSize()