com.sun.sgs.impl.util
Class CacheMap<K,V>

java.lang.Object
  com.sun.sgs.impl.util.CacheMap<K,V>

Type Parameters:

K - the key type

V - the value type

public class CacheMap<K,V>
extends Object

A map with values that are softly-referenced. An entry is removed if its associated value gets garbage-collected, or, if the cache was constructed with a timeout, and entry is removed (lazily) when the timeout expires for that entry. A timeout is typically used to have the implementation remove values that become stale after a certain period of time. The implementation ensures that a caller will not have access to stale entries (i.e., entries whose timeout has expired).

Constructor Summary

CacheMap()
Creates an instance of this class.

CacheMap(long entryTimeout)
Creates an instance of this class with the specified entryTimeout.

Method Summary

void	clear() Removes all associations from this map.
boolean	containsKey(K key) Checks if the map contains the specified key.
V	get(K key) Returns the value associated with given key, or null if the key is not found.
V	put(K key, V value) Associates a value with given key, returning the value previously associated with key, or null if none is found.
V	remove(K key) Removes the association for the given key, returning the value previously associated with the key, or null if the key is not found.

Methods inherited from class java.lang.Object

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

Constructor Detail

CacheMap

public CacheMap()

Creates an instance of this class.

CacheMap

public CacheMap(long entryTimeout)

Creates an instance of this class with the specified entryTimeout.

Parameters:

entryTimeout - an entry timeout, in milliseconds

Throws:

IllegalArgumentException - if entryTimeout is negative

Method Detail

put

public V put(K key,
             V value)

Associates a value with given key, returning the value previously associated with key, or null if none is found.

Parameters:

key - the key

value - the value

Returns:

the previous value or null

containsKey

public boolean containsKey(K key)

Checks if the map contains the specified key.

Parameters:

key - the key

Returns:

true if the map contains the key, else false

get

public V get(K key)

Returns the value associated with given key, or null if the key is not found.

Parameters:

key - the key

Returns:

the value associated with the key or null

remove

public V remove(K key)

Removes the association for the given key, returning the value previously associated with the key, or null if the key is not found.

Parameters:

key - the key

Returns:

the value previously associated with the key or null

clear

public void clear()

Removes all associations from this map.