rice.persistence
Interface Cache

All Superinterfaces:

Catalog

All Known Subinterfaces:

StorageManager

All Known Implementing Classes:

EmptyCache, LRUCache, StorageManagerImpl

public interface Cache

extends Catalog

This interface is the abstraction of something which provides a caching service. Implementations should take in parameters specific to the cache algorithm. Two implementations are provided, the LRUCache and GDSCache. This interface extends the Catalog interface, as the cache provides a Catalog service.

Version:

$Id: Cache.java 2682 2005-08-01 22:22:32Z jeffh $

Author:

jeffh

Method Summary

void	cache(Id id, java.io.Serializable metadata, java.io.Serializable obj, Continuation c) Caches an object in this storage.
long	getMaximumSize() Returns the maximum size of the cache, in bytes.
void	setMaximumSize(int size, Continuation c) Sets the maximum size of the cache, in bytes.
void	uncache(Id id, Continuation c) Removes the object from the list of cached objects.

Methods inherited from interface rice.persistence.Catalog

exists, flush, getMetadata, getObject, getSize, getTotalSize, rename, scan, scan, scanMetadata, scanMetadata, scanMetadataValuesHead, scanMetadataValuesNull, setMetadata

Method Detail

cache

public void cache(Id id,
                  java.io.Serializable metadata,
                  java.io.Serializable obj,
                  Continuation c)

Caches an object in this storage. This method is non-blocking. If the object has already been stored at the location id, this method has the effect of calling uncache(id) followed by cache(id, obj) . This method finishes by calling receiveResult() on the provided continuation with whether or not the object was cached. Note that the object may not actually be cached due to the cache replacement policy. Returns True if the cache actaully stores the object, else False (through receiveResult on c).

Parameters:

id - The object's id.

metadata - The object's metdatadata

obj - The object to cache.

c - The command to run once the operation is complete

uncache

public void uncache(Id id,
                    Continuation c)

Removes the object from the list of cached objects. This method is non-blocking. If the object was not in the cached list in the first place, nothing happens and False is returned. Returns True if the action succeeds, else False (through receiveResult on c).

Parameters:

c - The command to run once the operation is complete

id - DESCRIBE THE PARAMETER

getMaximumSize

public long getMaximumSize()

Returns the maximum size of the cache, in bytes. The result is returned via the receiveResult method on the provided Continuation with an Integer representing the size.

Returns:

The MaximumSize value

setMaximumSize

public void setMaximumSize(int size,
                           Continuation c)

Sets the maximum size of the cache, in bytes. Setting this value to a smaller value than the current value may result in object being evicted from the cache. Returns the success or failure of the setSize operation (through receiveResult on c).

Parameters:

size - The new maximum size, in bytes, of the cache.

c - The command to run once the operation is complete