org.zkoss.util
Class ThreadLocalCache<K,V>

java.lang.Object
  org.zkoss.util.ThreadLocalCache<K,V>

All Implemented Interfaces:

Cache<K,V>

public class ThreadLocalCache<K,V>
extends Object
implements Cache<K,V>

A cache that resides on the thread local memory. The performance is excellent since no need to synchronize the access. However, it takes more memory since each thread has its own map. In addition, it might cause hot re-deployment failed to free old classes if the map stores the references of the classes loaded by the Web Application class loader.

Since:

3.0.0

Author:

tomyeh

Field Summary

Fields inherited from interface org.zkoss.util.Cache

DEFAULT_LIFETIME, DEFAULT_MAX_SIZE

Constructor Summary

ThreadLocalCache()
Constructs a thread-local cache with the default setting: max size=128 and lifetime=30minutes.

ThreadLocalCache(int maxSize, int lifetime)
Constucts a thread-local cache with the specified max size and the lifetime.

Method Summary

void	clear() Clears all objects being cached.
boolean	containsKey(Object key) Returns whether the specified key is stored.
void	copyTo(Map<K,V> map) Deprecated. As of release 6.0.0, use Map.putAll(java.util.Map) instead.
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.
boolean	isEmpty() Returns whether the cache for the current thread is empty.
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

ThreadLocalCache

public ThreadLocalCache(int maxSize,
                        int lifetime)

Constucts a thread-local cache with the specified max size and the lifetime.

ThreadLocalCache

public ThreadLocalCache()

Constructs a thread-local cache with the default setting: max size=128 and lifetime=30minutes.

Method Detail

isEmpty

public boolean isEmpty()

Returns whether the cache for the current thread is empty.

copyTo

public void copyTo(Map<K,V> map)

Deprecated. As of release 6.0.0, use Map.putAll(java.util.Map) instead.

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-posive, they will be removed immediately.

See Also:

Cache.getLifetime()

getMaxSize

public int getMaxSize()

Returns the maximal allowed size.

Defalut: 128 (it is smaller than most cache since this cache one per thread). 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:

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()