org.camunda.bpm.engine.impl.db.entitymanager.cache

Class DbEntityCache

java.lang.Object

org.camunda.bpm.engine.impl.db.entitymanager.cache.DbEntityCache

public class DbEntityCache
extends Object

A simple first level cache for Entities.

Author:

Daniel Meyer

Field Summary

Fields

Modifier and Type	Field and Description
protected Map<Class<?>,Map<String,CachedDbEntity>>	cachedEntites The cache itself: maps entity types (classes) to maps indexed by id (primary key).
protected DbEntityCacheKeyMapping	cacheKeyMapping

Constructor Summary

Constructors

Constructor and Description
DbEntityCache()
DbEntityCache(DbEntityCacheKeyMapping cacheKeyMapping)

Method Summary

Methods

Modifier and Type	Method and Description
boolean	contains(DbEntity dbEntity) Allows checking whether the provided entity is present in the cache
<T extends DbEntity> T	get(Class<T> type, String id) get an object from the cache
List<CachedDbEntity>	getCachedEntities()
CachedDbEntity	getCachedEntity(Class<?> type, String id) Looks up an entity in the cache.
CachedDbEntity	getCachedEntity(DbEntity dbEntity) Looks up an entity in the cache.
<T extends DbEntity> List<T>	getEntitiesByType(Class<T> type)
boolean	isDeleted(DbEntity dbEntity) Allows checking whether the provided entity is present in the cache and is marked to be deleted.
boolean	isPersistent(DbEntity dbEntity) Allows checking whether the provided entity is present in the cache and is DbEntityState.PERSISTENT.
boolean	isTransient(DbEntity dbEntity) Allows checking whether the provided entity is present in the cache and is DbEntityState.TRANSIENT.
protected void	putInternal(CachedDbEntity entityToAdd)
void	putMerged(DbEntity e) Put a DbEntityState.MERGED object into the cache.
void	putPersistent(DbEntity e) Put a DbEntityState.PERSISTENT object into the cache.
void	putTransient(DbEntity e) Put a new, DbEntityState.TRANSIENT object into the cache.
void	remove(CachedDbEntity cachedDbEntity)
boolean	remove(DbEntity e) Remove an entity from the cache
void	setDeleted(DbEntity dbEntity) Sets an object to a deleted state.

Methods inherited from class java.lang.Object

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

Field Detail

cachedEntites

protected Map<Class<?>,Map<String,CachedDbEntity>> cachedEntites

The cache itself: maps entity types (classes) to maps indexed by id (primary key). The motivation for indexing by type (class) is a) multiple entities of different types could have the same value as primary key. In the process engine, TaskEntity and HistoricTaskEntity have the same id value. b) performance (?)

cacheKeyMapping

protected DbEntityCacheKeyMapping cacheKeyMapping

Constructor Detail

DbEntityCache

public DbEntityCache()

DbEntityCache

public DbEntityCache(DbEntityCacheKeyMapping cacheKeyMapping)

Method Detail

get

public <T extends DbEntity> T get(Class<T> type,
                         String id)

get an object from the cache

Parameters:

type - the type of the object

id - the id of the object

Returns:

the object or 'null' if the object is not in the cache

Throws:

ProcessEngineException - if an object for the given id can be found but is of the wrong type.

getEntitiesByType

public <T extends DbEntity> List<T> getEntitiesByType(Class<T> type)

getCachedEntity

public CachedDbEntity getCachedEntity(Class<?> type,
                             String id)

Looks up an entity in the cache.

Parameters:

type - the type of the object

id - the id of the CachedEntity to lookup

Returns:

the cached entity or null if the entity does not exist.

getCachedEntity

public CachedDbEntity getCachedEntity(DbEntity dbEntity)

Looks up an entity in the cache.

Parameters:

dbEntity - the entity for which the CachedEntity should be looked up

Returns:

the cached entity or null if the entity does not exist.

putTransient

public void putTransient(DbEntity e)

Put a new, DbEntityState.TRANSIENT object into the cache.

Parameters:

e - the object to put into the cache

putPersistent

public void putPersistent(DbEntity e)

Put a DbEntityState.PERSISTENT object into the cache.

Parameters:

e - the object to put into the cache

putMerged

public void putMerged(DbEntity e)

Put a DbEntityState.MERGED object into the cache.

Parameters:

e - the object to put into the cache

putInternal

protected void putInternal(CachedDbEntity entityToAdd)

remove

public boolean remove(DbEntity e)

Remove an entity from the cache

Parameters:

e - the entity to remove

Returns:

remove

public void remove(CachedDbEntity cachedDbEntity)

Parameters:

cachedDbEntity -

contains

public boolean contains(DbEntity dbEntity)

Allows checking whether the provided entity is present in the cache

Parameters:

dbEntity - the entity to check

Returns:

true if the the provided entity is present in the cache

isPersistent

public boolean isPersistent(DbEntity dbEntity)

Allows checking whether the provided entity is present in the cache and is DbEntityState.PERSISTENT.

Parameters:

dbEntity - the entity to check

Returns:

true if the provided entity is present in the cache and is DbEntityState.PERSISTENT.

isDeleted

public boolean isDeleted(DbEntity dbEntity)

Allows checking whether the provided entity is present in the cache and is marked to be deleted.

Parameters:

dbEntity - the entity to check

Returns:

true if the provided entity is present in the cache and is marked to be deleted

isTransient

public boolean isTransient(DbEntity dbEntity)

Allows checking whether the provided entity is present in the cache and is DbEntityState.TRANSIENT.

Parameters:

dbEntity - the entity to check

Returns:

true if the provided entity is present in the cache and is DbEntityState.TRANSIENT.

getCachedEntities

public List<CachedDbEntity> getCachedEntities()

setDeleted

public void setDeleted(DbEntity dbEntity)

Sets an object to a deleted state. It will not be removed from the cache but transition to one of the DELETED states, depending on it's current state.

Parameters:

dbEntity - the object to mark deleted.