org.zkoss.util
Interface Cache<K,V>

All Known Implementing Classes:

CacheMap, FastReadCache, MultiCache, ResourceCache, ResourceCache

public interface Cache<K,V>

Represents a cache. The interface is similar to java.util.Map but simpler to implement.

Since:

3.0.0

Author:

tomyeh

Field Summary

static int	DEFAULT_LIFETIME The default minimal lifetime, unit=milliseconds.
static int	DEFAULT_MAX_SIZE The default maximal allowed size.

Method Summary

void	clear() Clears all objects being cached.
boolean	containsKey(java.lang.Object key) Returns whether the specified key is stored.
V	get(java.lang.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(java.lang.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.

Field Detail

DEFAULT_LIFETIME

static final int DEFAULT_LIFETIME

The default minimal lifetime, unit=milliseconds. It is 30 minutes.

See Also:

Constant Field Values

DEFAULT_MAX_SIZE

static final int DEFAULT_MAX_SIZE

The default maximal allowed size. It is 512.

See Also:

Constant Field Values

Method Detail

containsKey

boolean containsKey(java.lang.Object key)

Returns whether the specified key is stored.

get

V get(java.lang.Object key)

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

put

V put(K key,
      V value)

Stores an object to the cache.

Returns:

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

remove

V remove(java.lang.Object key)

Removes an object from the cache.

Returns:

the object if found.

clear

void clear()

Clears all objects being cached.

getLifetime

int getLifetime()

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

See Also:

getMaxSize()

setLifetime

void setLifetime(int lifetime)

Sets the minimal lifetime. Default: DEFAULT_LIFETIME.

Parameters:

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

See Also:

getLifetime()

getMaxSize

int getMaxSize()

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

See Also:

getLifetime()

setMaxSize

void setMaxSize(int maxsize)

Sets the maximal allowed size.

See Also:

getMaxSize()