com.communote.server.core.common.caching

Class Cache

java.lang.Object

com.communote.server.core.common.caching.Cache

Direct Known Subclasses:

EhCache, NoCache

public abstract class Cache
extends Object

An abstract cache providing basic caching features. The get method follows a self-populating strategy.

Author:

Communote GmbH - http://www.communote.com/

Constructor Summary

Constructors

Constructor and Description
Cache()

Method Summary

Modifier and Type	Method and Description
<K extends CacheKey,T extends Serializable> T	get(K key, AccessRestrictedCacheElementProvider<K,T> provider) This method checks the access for the given item, before it returns it.
<K extends CacheKey,T extends Serializable> T	get(K key, CacheElementProvider<K,T> provider) Retrieves an element identified by the provided key from the cache.
protected abstract CacheElementWrapper<Serializable>	handleGet(String cacheKey) Retrieves an element identified by the provided key from the cache.
protected abstract void	handleInvalidate(String cacheKey) Invalidates the data stored under the supplied key.
protected abstract void	handlePut(String cacheKey, CacheElementWrapper<Serializable> cacheElement, int timeToLive) Stores an element under the key cacheKey in the cache.
<K extends CacheKey,T extends Serializable> void	invalidate(K key, CacheElementProvider<K,T> provider) Invalidates a cached element that has the key cacheKey.
void	invalidateAll(CacheElementProvider<?,?> provider) Invalidate all cached items that were retrieved from the given provider.
void	invalidateAllOfCurrentClient(CacheElementProvider<?,?> provider) Invalidate all cached items that were retrieved from the given provider.
<K extends CacheKey,T extends Serializable> void	put(K key, CacheElementProvider<K,T> provider, T data) Stores some data in the cache under the provided key.

Methods inherited from class java.lang.Object

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

Constructor Detail

Cache

public Cache()

Method Detail

get

public <K extends CacheKey,T extends Serializable> T get(K key,
                                                         AccessRestrictedCacheElementProvider<K,T> provider)
                                                  throws AuthorizationException

This method checks the access for the given item, before it returns it.

Type Parameters:

K - the type of the key

T - the type of the cached element

Parameters:

key - the key to use

provider - The provider for asserting access and loading the requested element in case it is not cached.

Returns:

the cached element or null if the element provider returned null or threw a CacheElementProviderException

Throws:

AuthorizationException - Thrown, if the user has no access to the given item.

get

public <K extends CacheKey,T extends Serializable> T get(K key,
                                                         CacheElementProvider<K,T> provider)

Retrieves an element identified by the provided key from the cache. In case this element is not yet cached it will be cached after loading it from the element provider. If the element provider cannot provide the requested element nothing will be cached.

Type Parameters:

K - the type of the key

T - the type of the cached element

Parameters:

key - the key to use

provider - the provider for loading the requested element in case it is not cached

Returns:

the cached element or null if the element provider returned null or threw a CacheElementProviderException

handleGet

protected abstract CacheElementWrapper<Serializable> handleGet(String cacheKey)
                                                        throws CacheException

Retrieves an element identified by the provided key from the cache.

Parameters:

cacheKey - the key used for storing the element in the cache

Returns:

the cached element or null if there is no element cached that has the supplied cacheKey or the cached element is expired

Throws:

CacheException - when there are problems with the backend

handleInvalidate

protected abstract void handleInvalidate(String cacheKey)
                                  throws CacheException

Invalidates the data stored under the supplied key.

Parameters:

cacheKey - the key used for caching

Throws:

CacheException - when the invalidation failed

handlePut

protected abstract void handlePut(String cacheKey,
                                  CacheElementWrapper<Serializable> cacheElement,
                                  int timeToLive)
                           throws CacheException

Stores an element under the key cacheKey in the cache.

Parameters:

cacheKey - the key used for caching and retrieving

cacheElement - the element to be cached; never null

timeToLive - the time in seconds until the item will expire. A negative value indicates eternal caching.

Throws:

CacheException - when caching failed

invalidate

public <K extends CacheKey,T extends Serializable> void invalidate(K key,
                                                                   CacheElementProvider<K,T> provider)
                                                            throws CacheException

Invalidates a cached element that has the key cacheKey.

Type Parameters:

K - the type of the key

T - the type of the cached element

Parameters:

key - the key to use

provider - the associated provider

Throws:

CacheException - when the invalidation failed

invalidateAll

public void invalidateAll(CacheElementProvider<?,?> provider)

Invalidate all cached items that were retrieved from the given provider. Note: this will invalidate the cached items of all clients

Parameters:

provider - the provider from which the cached items to be invalidated were loaded

invalidateAllOfCurrentClient

public void invalidateAllOfCurrentClient(CacheElementProvider<?,?> provider)

Invalidate all cached items that were retrieved from the given provider.

Parameters:

provider - the provider from which the cached items to be invalidated were loaded

put

public <K extends CacheKey,T extends Serializable> void put(K key,
                                                            CacheElementProvider<K,T> provider,
                                                            T data)
                                                     throws CacheException

Stores some data in the cache under the provided key.

Type Parameters:

K - the type of the key

T - the type of the data to be cached

Parameters:

key - the key to use

provider - the associated provider

data - the data to be cached; can be null

Throws:

CacheException - when caching failed