rice.persistence
Class StorageManagerImpl

java.lang.Object
  rice.persistence.StorageManagerImpl

All Implemented Interfaces:

Cache, Catalog, Storage, StorageManager

public class StorageManagerImpl

extends java.lang.Object

implements StorageManager

This class provides both persistent and caching services to external applications. Building the StorageManager requires a Storage object, to provide the back-end storage, and a Cache to serve as a cache. Note that this implementation has seperate areas for the Cache and Storage, but the next version will allow the cache to use the unused storage space.

Version:

$Id: pretty.settings,v 1.3 2005/03/11 20:22:33 jeffh Exp $

Author:

jeffh

Constructor Summary

StorageManagerImpl(IdFactory factory, Storage storage, Cache cache)
Builds a StorageManager given a Storage object to provide storage services and a Cache object to provide caching services.

Method Summary

void	cache(Id id, java.io.Serializable metadata, java.io.Serializable obj, Continuation c) Caches an object in this storage.
boolean	exists(Id id) Returns whether or not an object is present in the location id .
void	flush(Continuation c) Method which is used to erase all data stored in the Catalog.
Cache	getCache() Returns the cache object used by this StorageManager
long	getMaximumSize() Returns the maximum size of the cache, in bytes.
java.io.Serializable	getMetadata(Id id) Returns the metadata associated with the provided object, or null if no metadata exists.
void	getObject(Id id, Continuation c) Returns the object identified by the given id, or null if there is no cooresponding object (through receiveResult on c).
int	getSize() Returns the number of Ids currently stored in the catalog
Storage	getStorage() Returns the permantent storage object used by this StorageManager
long	getTotalSize() Returns the total size of the stored data in bytes.The result is returned via the receiveResult method on the provided Continuation with an Integer representing the size.
void	rename(Id oldId, Id newId, Continuation c) Renames the given object to the new id.
IdSet	scan() Return all objects currently stored by this catalog NOTE: This method blocks so if the behavior of this method changes and no longer stored in memory, this method may be deprecated.
IdSet	scan(IdRange range) Return the objects identified by the given range of ids.
java.util.SortedMap	scanMetadata() Returns a map which contains keys mapping ids to the associated metadata.
java.util.SortedMap	scanMetadata(IdRange range) Returns a map which contains keys mapping ids to the associated metadata.
java.util.SortedMap	scanMetadataValuesHead(java.lang.Object value) Returns the submapping of ids which have metadata less than the provided value.
java.util.SortedMap	scanMetadataValuesNull() Returns the submapping of ids which have metadata null
void	setMaximumSize(int size, Continuation c) Sets the maximum size of the cache, in bytes.
void	setMetadata(Id id, java.io.Serializable metadata, Continuation command) Updates the metadata stored under the given key to be the provided value.
void	store(Id id, java.io.Serializable metadata, java.io.Serializable obj, Continuation c) Stores an object in this storage.
void	uncache(Id id, Continuation c) Removes the object from the list of cached objects.
void	unstore(Id id, Continuation c) Removes the object from the list of stored objects.

Methods inherited from class java.lang.Object

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

Constructor Detail

StorageManagerImpl

public StorageManagerImpl(IdFactory factory,
                          Storage storage,
                          Cache cache)

Builds a StorageManager given a Storage object to provide storage services and a Cache object to provide caching services.

Parameters:

factory - The factory to use for Id creation

storage - The Storage object which will serve as the persistent storage.

cache - The Cache object which will serve as the cache.

Method Detail

getStorage

public Storage getStorage()

Returns the permantent storage object used by this StorageManager

Specified by:

getStorage in interface StorageManager

Returns:

The storage of this storage manager

getCache

public Cache getCache()

Returns the cache object used by this StorageManager

Specified by:

getCache in interface StorageManager

Returns:

The cache of this storage manager

getObject

public void getObject(Id id,
                      Continuation c)

Returns the object identified by the given id, or null if there is no cooresponding object (through receiveResult on c).

Specified by:

getObject in interface Catalog

Parameters:

id - The id of the object in question.

c - The command to run once the operation is complete

getMetadata

public java.io.Serializable getMetadata(Id id)

Returns the metadata associated with the provided object, or null if no metadata exists. The metadata must be stored in memory, so this operation is guaranteed to be fast and non-blocking.

Specified by:

getMetadata in interface Catalog

Parameters:

id - The id for which the metadata is needed

Returns:

The metadata, or null of non exists

getTotalSize

public long getTotalSize()

Returns the total size of the stored data in bytes.The result is returned via the receiveResult method on the provided Continuation with an Integer representing the size.

Specified by:

getTotalSize in interface Catalog

Returns:

The TotalSize value

getSize

public int getSize()

Returns the number of Ids currently stored in the catalog

Specified by:

getSize in interface Catalog

Returns:

The number of ids in the catalog

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.

Specified by:

getMaximumSize in interface Cache

Returns:

The MaximumSize value

setMetadata

public void setMetadata(Id id,
                        java.io.Serializable metadata,
                        Continuation command)

Updates the metadata stored under the given key to be the provided value. As this may require a disk access, the requestor must also provide a continuation to return the result to.

Specified by:

setMetadata in interface Catalog

Parameters:

id - The id for the metadata

metadata - The metadata to store

command - The new Metadata 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).

Specified by:

setMaximumSize in interface Cache

Parameters:

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

c - The command to run once the operation is complete

exists

public boolean exists(Id id)

Returns whether or not an object is present in the location id .

Specified by:

exists in interface Catalog

Parameters:

id - The id of the object in question.

Returns:

Whether or not an object is present at id.

rename

public void rename(Id oldId,
                   Id newId,
                   Continuation c)

Renames the given object to the new id. This method is potentially faster than store/cache and unstore/uncache.

Specified by:

rename in interface Catalog

Parameters:

oldId - The id of the object in question.

newId - The new id of the object in question.

c - The command to run once the operation is complete

scan

public IdSet scan(IdRange range)

Return the objects identified by the given range of ids. The IdSet returned contains the Ids of the stored objects. The range is partially inclusive, the lower range is inclusive, and the upper exclusive. NOTE: This method blocks so if the behavior of this method changes and no longer stored in memory, this method may be deprecated.

Specified by:

scan in interface Catalog

Parameters:

range - The range to query

Returns:

The idset containg the keys

scan

public IdSet scan()

Return all objects currently stored by this catalog NOTE: This method blocks so if the behavior of this method changes and no longer stored in memory, this method may be deprecated.

Specified by:

scan in interface Catalog

Returns:

The idset containg the keys

scanMetadata

public java.util.SortedMap scanMetadata(IdRange range)

Returns a map which contains keys mapping ids to the associated metadata.

Specified by:

scanMetadata in interface Catalog

Parameters:

range - The range to query

Returns:

The map containg the keys

scanMetadata

public java.util.SortedMap scanMetadata()

Returns a map which contains keys mapping ids to the associated metadata.

Specified by:

scanMetadata in interface Catalog

Returns:

The treemap mapping ids to metadata

scanMetadataValuesHead

public java.util.SortedMap scanMetadataValuesHead(java.lang.Object value)

Returns the submapping of ids which have metadata less than the provided value.

Specified by:

scanMetadataValuesHead in interface Catalog

Parameters:

value - The maximal metadata value

Returns:

The submapping

scanMetadataValuesNull

public java.util.SortedMap scanMetadataValuesNull()

Returns the submapping of ids which have metadata null

Specified by:

scanMetadataValuesNull in interface Catalog

Returns:

The submapping

store

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

Stores 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 unstore(id) followed by store(id, obj) . This method finishes by calling receiveResult() on the provided continuation with the success or failure of the store. Returns True if the action succeeds, else False (through receiveResult on c).

Specified by:

store in interface Storage

Parameters:

id - The object's id.

metadata - The object's metadata

obj - The object to store.

c - The command to run once the operation is complete

unstore

public void unstore(Id id,
                    Continuation c)

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

Specified by:

unstore in interface Storage

Parameters:

c - The command to run once the operation is complete

id - DESCRIBE THE PARAMETER

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 uncachr(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).

Specified by:

cache in interface Cache

Parameters:

id - The object's id.

metadata - The object's metadata

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).

Specified by:

uncache in interface Cache

Parameters:

c - The command to run once the operation is complete

id - DESCRIBE THE PARAMETER

flush

public void flush(Continuation c)

Method which is used to erase all data stored in the Catalog. Use this method with care!

Specified by:

flush in interface Catalog

Parameters:

c - The command to run once done