de.bb.util

Class PersistantTimedLRUCache

java.lang.Object

de.bb.util.TimedLRUCache

de.bb.util.PersistantTimedLRUCache

public class PersistantTimedLRUCache
extends TimedLRUCache

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 inherited from class de.bb.util.TimedLRUCache

lifeTime, lifeTimeRange

Constructor Summary

Constructors

Constructor and Description
PersistantTimedLRUCache(java.lang.String folder, long defaultLifeTime) Create a new PersistantTimedLRUCache instance.
PersistantTimedLRUCache(java.lang.String folder, long defaultLifeTime, double ratio) Create a new PresistantTimedLRUCache instance.

Method Summary

Methods

Modifier and Type	Method and Description
java.lang.Object	get(java.lang.Object key) get an object from the cache.
java.lang.Object	getOutDated(java.lang.Object key) Returns the out dated value if there is any.
java.lang.Object	put(java.lang.Object key, java.lang.Object value) Put a value into the cache using the specified key.
java.lang.Object	remove(java.lang.Object key) get an object from the cache.
java.lang.String	toString() Some verbose information about the cache.

Methods inherited from class de.bb.util.TimedLRUCache

__sget, __sput, clear, put, setLifeTime, size

Methods inherited from class java.lang.Object

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

Constructor Detail

PersistantTimedLRUCache

public PersistantTimedLRUCache(java.lang.String folder,
                       long defaultLifeTime)

Create a new PersistantTimedLRUCache instance.

Parameters:

folder - the folder to write the files to.

defaultLifeTime - the default life time in milli seconds.

PersistantTimedLRUCache

public PersistantTimedLRUCache(java.lang.String folder,
                       long defaultLifeTime,
                       double ratio)

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

Parameters:

folder - the folder to write the files to.

defaultLifeTime - the default life time in milli seconds.

ratio - define the ratio for the underlying cache.

Method Detail

get

public java.lang.Object get(java.lang.Object key)

get an object from the cache. This implementation tries to load it from disk, if it is not in the memory.

Overrides:

get in class TimedLRUCache

Parameters:

key - the key to perform the lookup

Returns:

the object if found, or null if not found or outdated.

remove

public java.lang.Object remove(java.lang.Object key)

get an object from the cache. This implementation tries to load it from disk, if it is not in the memory.

Overrides:

remove in class TimedLRUCache

Parameters:

key - the key to perform the lookup

Returns:

the object if found, or null if not found or outdated.

getOutDated

public java.lang.Object getOutDated(java.lang.Object key)

Returns the out dated value if there is any. Useful to reuse the outdate value while calculating the new one in the background for further gets.

Parameters:

key - the key to lookup

Returns:

an entrie if it exists.

put

public java.lang.Object put(java.lang.Object key,
                   java.lang.Object value)

Description copied from class: TimedLRUCache

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

Overrides:

put in class TimedLRUCache

Parameters:

key - a key object - not null!

value - a value object

toString

public java.lang.String toString()

Description copied from class: TimedLRUCache

Some verbose information about the cache.

Overrides:

toString in class TimedLRUCache

Returns:

a String containing some verbose information about the cache.