de.bb.util

Class TimedLRUCache<K,V>

java.lang.Object

de.bb.util.TimedLRUCache<K,V>

Direct Known Subclasses:

PersistantTimedLRUCache

public class TimedLRUCache<K,V>
extends java.lang.Object

A LRU cache with limited life time to ensure refreshing of content. This implementation utilizes the memory friendly de.bb.util.LRUCache. after max life time is reached.

Field Summary

Fields

Modifier and Type	Field and Description
protected long	lifeTime the life time for objects.
protected long	lifeTimeRange since we add randomness the range for deviations is calculated and held.

Constructor Summary

Constructors

Constructor and Description
TimedLRUCache(long defaultLifeTime) Create a new TimedLRUCache instance.
TimedLRUCache(long defaultLifeTime, double ratio) Create a new TimedLRUCache instance.

Method Summary

Methods

Modifier and Type	Method and Description
protected de.bb.util.TimedLRUCache.Valuette<V>	__sget(K key) Get a Valuette for the key.
protected java.lang.Object	__sput(K key, de.bb.util.TimedLRUCache.Valuette<V> v) Put a Valuette for the specified key.
void	clear() Removes all keys and values from the underlying cache.
V	get(java.lang.Object key) Returns the value to the specified key.
V	put(K key, V value) Put a value into the cache using the specified key.
void	put(K key, V value, long specificLifeTime) Put a value into the cache using the specified key.
V	remove(java.lang.Object key) Removes the associated value from the underlying cache.
void	setLifeTime(long defaultLifeTime) Set the default time out.
int	size() Returns the size of the underlying cache.
java.lang.String	toString() Some verbose information about the cache.

Methods inherited from class java.lang.Object

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

Field Detail

lifeTime

protected long lifeTime

the life time for objects.

lifeTimeRange

protected long lifeTimeRange

since we add randomness the range for deviations is calculated and held.

Constructor Detail

TimedLRUCache

public TimedLRUCache(long defaultLifeTime)

Create a new TimedLRUCache instance.

Parameters:

defaultLifeTime - the default life time in milliseconds.

TimedLRUCache

public TimedLRUCache(long defaultLifeTime,
             double ratio)

Create a new TimedLRUCache instance. Also specify the ratio (hard references / soft references) for the underlying cache.

Parameters:

defaultLifeTime - the default life time in milliseconds.

ratio - define the ratio for the underlying cache.

Method Detail

setLifeTime

public void setLifeTime(long defaultLifeTime)

Set the default time out.

Parameters:

defaultLifeTime - set a new default life time.

put

public void put(K key,
       V value,
       long specificLifeTime)

Put a value into the cache using the specified key. Apply the specified lifeTime instead of the default life time.

Parameters:

key - a key object - not null!

value - a value object

specificLifeTime - a life time in milliseconds

put

public V put(K key,
    V value)

Put a value into the cache using the specified key. The default life time is applied.

Parameters:

key - a key object - not null!

value - a value object

get

public V get(java.lang.Object key)

Returns the value to the specified key. Returns the value if

• the value is still in the underlying cache
• and the life time has not expired

otherwise return null;

Parameters:

key - a key object - not null!

Returns:

the value or null;

__sget

protected de.bb.util.TimedLRUCache.Valuette<V> __sget(K key)

Get a Valuette for the key.

Parameters:

key - the key

Returns:

the Valuette or null.

__sput

protected java.lang.Object __sput(K key,
                      de.bb.util.TimedLRUCache.Valuette<V> v)

Put a Valuette for the specified key.

Parameters:

key - the key

v - the Valuette

remove

public V remove(java.lang.Object key)

Removes the associated value from the underlying cache.

Parameters:

key - a key object - not null!

Returns:

the removed object if it exists.

clear

public void clear()

Removes all keys and values from the underlying cache.

size

public int size()

Returns the size of the underlying cache.

Returns:

the size of the underlying cache.

toString

public java.lang.String toString()

Some verbose information about the cache.

Overrides:

toString in class java.lang.Object

Returns:

a String containing some verbose information about the cache.