com.sun.jdo.spi.persistence.support.sqlstore.impl

Class VersionConsistencyCacheImpl

java.lang.Object

com.sun.jdo.spi.persistence.support.sqlstore.impl.VersionConsistencyCacheImpl

All Implemented Interfaces:

VersionConsistencyCache

public class VersionConsistencyCacheImpl
extends Object
implements VersionConsistencyCache

A 2-level cache of StateManager instances (i.e., a map of maps). The inner map is a BucketizedHashtable or a LRU cache, depending on parameter given at construction.

Author:

Dave Bristor

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	VersionConsistencyCacheImpl(boolean highPerf) Creates a cache with desired performance.

Method Summary

Modifier and Type	Method and Description
void	addPCType(Class pcType) This implementation does nothing.
StateManager	get(Class pcType, Object oid) Returns an SM, if found, else null.
boolean	isHighPerf()
StateManager	put(Class pcType, Object oid, StateManager sm) Puts the given StateManager into a map that is keyed by the given OID.
StateManager	remove(Class pcType, Object oid) Removes entry based on pc and oid.
void	removePCType(Class pcType) Removes the map for the given pcType and all its elements.
int	size()

Methods inherited from class java.lang.Object

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

Constructor Detail

VersionConsistencyCacheImpl

protected VersionConsistencyCacheImpl(boolean highPerf)

Creates a cache with desired performance. This constructor is expected to be used for unit testing ONLY.

Parameters:

highPerf - If true, use LruCache, else use BucketizedHashtable.

Method Detail

put

public StateManager put(Class pcType,
                        Object oid,
                        StateManager sm)

Description copied from interface: VersionConsistencyCache

Puts the given StateManager into a map that is keyed by the given OID. We anticipate that implementations will want to use a two-level map, and so the pc's class can be used as a key into a map to access a second map, which would be that keyed by OID.

Specified by:

put in interface VersionConsistencyCache

Parameters:

pcType - class of instance, used as key in outer map.

oid - Object id, used as key in inner map.

sm - StateManager bound to oid in inner map.

See Also:

VersionConsistencyCache.put(java.lang.Class, java.lang.Object, com.sun.jdo.spi.persistence.support.sqlstore.StateManager)

get

public StateManager get(Class pcType,
                        Object oid)

Description copied from interface: VersionConsistencyCache

Returns an SM, if found, else null.

Specified by:

get in interface VersionConsistencyCache

Parameters:

pcType - class of instance, used as key in outer map.

oid - Object id, used as key in inner map.

See Also:

VersionConsistencyCache.get(java.lang.Class, java.lang.Object)

remove

public StateManager remove(Class pcType,
                           Object oid)

Description copied from interface: VersionConsistencyCache

Removes entry based on pc and oid. If map is empty after remove, removes it from its containint map.

Specified by:

remove in interface VersionConsistencyCache

Parameters:

pcType - class of instance, used as key in outer map.

oid - Object id, used as key in inner map.

See Also:

VersionConsistencyCache.remove(java.lang.Class, java.lang.Object)

addPCType

public void addPCType(Class pcType)

This implementation does nothing. Instead, we create buckets for each pcType as-needed; see put(java.lang.Class, java.lang.Object, com.sun.jdo.spi.persistence.support.sqlstore.StateManager)

Specified by:

addPCType in interface VersionConsistencyCache

Parameters:

pcType - class of instance, used as key in outer map.

removePCType

public void removePCType(Class pcType)

Description copied from interface: VersionConsistencyCache

Removes the map for the given pcType and all its elements.

Specified by:

removePCType in interface VersionConsistencyCache

Parameters:

pcType - class of instance, used as key in outer map.

See Also:

VersionConsistencyCache.removePCType(java.lang.Class)

size

public int size()

Returns:

the number of elements in the cache.

isHighPerf

public boolean isHighPerf()

Returns:

true if this cache is based on LRU cache; false otherwise.