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

Fields

Modifier and Type	Field and Description
static int	DEFAULT_LIFETIME The default minimal lifetime, unit=milliseconds.
static int	DEFAULT_MAX_SIZE The default maximal allowed size.

Method Summary

Methods

Modifier and Type	Method and Description
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-positive, they will be removed immediately.

See Also:

getLifetime()

getMaxSize

int getMaxSize()

Returns the maximal allowed size. Default: 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()