rice.persistence
Class MemoryStorage

java.lang.Object
  rice.persistence.MemoryStorage

All Implemented Interfaces:

Catalog, Storage

public class MemoryStorage

extends java.lang.Object

implements Storage

This class is an implementation of Storage which provides in-memory storage. This class is specifically *NOT* designed to provide persistent storage, and simply functions as an enhanced hash table.

Version:

$Id: pretty.settings 2305 2005-03-11 20:22:33Z jeffh $

Author:

jeffh

Constructor Summary

MemoryStorage(IdFactory factory)
Builds a MemoryStorage object.

Method Summary

boolean	exists(Id id) Returns whether or not the provided id exists
void	flush(Continuation c) Method which is used to erase all data stored in the Storage.
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
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	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 the object under the key id.
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

MemoryStorage

public MemoryStorage(IdFactory factory)

Builds a MemoryStorage object.

Parameters:

factory - The factory to build protocol-specific Ids from.

Method Detail

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

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

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

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

flush

public void flush(Continuation c)

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

Specified by:

flush in interface Catalog

Parameters:

c - The command to run once done

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

store

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

Stores the object under the key id. If there is already an object under id, that object is replaced. This method completes by calling recieveResult() of the provided continuation with the success or failure of the operation.

Specified by:

store in interface Storage

Parameters:

obj - The object to be made persistent.

id - The object's id.

metadata - The object's metadata

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. If the object was not in the cached list in the first place, nothing happens and false is returned. This method completes by calling recieveResult() of the provided continuation with the success or failure of the operation.

Specified by:

unstore in interface Storage

Parameters:

id - The object's persistence id

c - The command to run once the operation is complete

exists

public boolean exists(Id id)

Returns whether or not the provided id exists

Specified by:

exists in interface Catalog

Parameters:

id - The id to check

Returns:

Whether or not the given id is stored

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 the guys don't fit 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