Package org.dspace.services.caching.model

Class MapCache

java.lang.Object

org.dspace.services.caching.model.MapCache

All Implemented Interfaces:

Cache

public final class MapCache
extends Object
implements Cache

This is a simple Cache that just uses a map to store the cache values. Used for the request and thread caches.

Author:

Aaron Zeckoski (azeckoski @ gmail.com)

Field Summary

Fields

Modifier and Type	Field	Description
protected CacheConfig	cacheConfig
protected String	name

Constructor Summary

Constructors

Constructor	Description
MapCache(String name, CacheConfig cacheConfig)

Method Summary

Modifier and Type	Method	Description
void	clear()	Clear out all cached items from this cache.
boolean	exists(String key)	Check if a key exists in the cache.
Object	get(String key)	Gets an object from the cache if it can be found (maybe be a null).
Map<String,Object>	getCache()
CacheConfig	getConfig()	Returns a readable object which has the configuration used by this cache in it.
List<String>	getKeys()	Provides a method for finding out what keys are currently in the cache or getting all items out of the cache.
String	getName()	Get the unique name which identifies this cache.
Object	look(String key)	Gets an object from the cache without causing it to be refreshed or renewed.
void	put(String key, Object value)	Puts an object in the cache which is identified by this key.
boolean	remove(String key)	Removes an object from the cache if it exists or does nothing if it does not.
int	size()	How many items does this cache hold?
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

name

protected String name

cacheConfig

protected CacheConfig cacheConfig

Constructor Detail

MapCache

public MapCache(String name,
                CacheConfig cacheConfig)

Method Detail

getCache

public Map<String,Object> getCache()

clear

public void clear()

Description copied from interface: Cache

Clear out all cached items from this cache.

Specified by:

clear in interface Cache

exists

public boolean exists(String key)

Description copied from interface: Cache

Check if a key exists in the cache.

Specified by:

exists in interface Cache

Parameters:

key - the key for an item in the cache

Returns:

true if the object was removed or false if it could not be found in the cache

get

public Object get(String key)

Description copied from interface: Cache

Gets an object from the cache if it can be found (maybe be a null). Use the exists check to see if the object is in the cache before retrieving.

Specified by:

get in interface Cache

Parameters:

key - the key for an item in the cache

Returns:

the cached object (may be null) OR null if the cache object cannot be found

getKeys

public List<String> getKeys()

Description copied from interface: Cache

Provides a method for finding out what keys are currently in the cache or getting all items out of the cache. The keys are returned in no particular order.

NOTE: that this is actually quite costly in most cases and should only be used when really needed. It is much better to fetch the items you actually need directly using Cache.get(String).

Specified by:

getKeys in interface Cache

Returns:

the list of all keys currently in this cache

getConfig

public CacheConfig getConfig()

Description copied from interface: Cache

Returns a readable object which has the configuration used by this cache in it.

Specified by:

getConfig in interface Cache

Returns:

the object indicating the configuration of this cache

getName

public String getName()

Description copied from interface: Cache

Get the unique name which identifies this cache.

Specified by:

getName in interface Cache

Returns:

string

look

public Object look(String key)

Description copied from interface: Cache

Gets an object from the cache without causing it to be refreshed or renewed. Like Cache.get(String) except that it keeps the cache from refreshing the item that was retrieved.

Specified by:

look in interface Cache

Parameters:

key - the key for an item in the cache

Returns:

the cached object (may be null) OR null if the cache object cannot be found

See Also:

Cache.get(String)

put

public void put(String key,
                Object value)

Description copied from interface: Cache

Puts an object in the cache which is identified by this key. Will overwrite an existing object if one is already using this key.

Specified by:

put in interface Cache

Parameters:

key - the key for an item in the cache

value - an object (this can be a null, e.g. to cache a miss)

remove

public boolean remove(String key)

Description copied from interface: Cache

Removes an object from the cache if it exists or does nothing if it does not.

Specified by:

remove in interface Cache

Parameters:

key - the key for an item in the cache

Returns:

true if the object was removed or false if it could not be found in the cache

size

public int size()

Description copied from interface: Cache

How many items does this cache hold?

Specified by:

size in interface Cache

Returns:

the count of the number of active items in the cache. Does not include expired items.

toString

public String toString()

Overrides:

toString in class Object