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com.tangosol.coherence.jpa
Class JpaCacheLoader

java.lang.Object
com.tangosol.util.Base
com.tangosol.coherence.jpa.JpaCacheLoader

All Implemented Interfaces:

CacheLoader

Direct Known Subclasses:

JpaCacheStore

public class JpaCacheLoader

extends Base

implements CacheLoader

JPA implementation of the CacheLoader interface.

Use this class as a load-only implementation that uses any JPA implementation to load entities from a data store. The entities must be mapped to the data store and a JPA persistence unit configuration must exist.

Use the JpaCacheStore class for a full load and store implementation.

Author:

mlk 2007.04.20, jh 2007.05.18

See Also:

JpaCacheStore

Field Summary

protected javax.persistence.EntityManagerFactory	m_emf The EntityManagerFactory from which EntityManager instances are obtained.
protected java.lang.Class	m_sEntityClass The entity class that this CacheLoader is managing.
protected java.lang.String	m_sEntityName Name of the entity that this CacheLoader is managing.
protected static java.util.Map	s_mapFactories Map of all shared entity manager factories for all persistence units.

Constructor Summary

JpaCacheLoader(java.lang.String sEntityName, java.lang.String sEntityClassName, java.lang.String sUnitName)
Constructor which accepts an entity name, class name, and persistence unit name.

JpaCacheLoader(java.lang.String sEntityName, java.lang.String sEntityClassName, java.lang.String sUnitName, java.lang.ClassLoader loader)
Constructor which accepts an entity name, class name, persistence unit name, and classloader.

Method Summary

protected javax.persistence.EntityManager	getEntityManager() Creates and returns an EntityManager.
protected void	initialize(java.lang.String sEntityName, java.lang.String sEntityClassName, java.lang.String sUnitName, java.lang.ClassLoader loader) Initialize this instance with the relevant metadata for the entity being stored.
java.lang.Object	load(java.lang.Object oKey) Return the value associated with the specified key, or null if the key does not have an associated value in the underlying store.
java.util.Map	loadAll(java.util.Collection colKeys) Return the values associated with each the specified keys in the passed collection.

Field Detail

s_mapFactories

protected static final java.util.Map s_mapFactories

Map of all shared entity manager factories for all persistence units.

m_sEntityName

protected java.lang.String m_sEntityName

Name of the entity that this CacheLoader is managing.

m_sEntityClass

protected java.lang.Class m_sEntityClass

The entity class that this CacheLoader is managing.

m_emf

protected javax.persistence.EntityManagerFactory m_emf

The EntityManagerFactory from which EntityManager instances are obtained.

Constructor Detail

JpaCacheLoader

public JpaCacheLoader(java.lang.String sEntityName,
                      java.lang.String sEntityClassName,
                      java.lang.String sUnitName)

Constructor which accepts an entity name, class name, and persistence unit name.

Parameters:

sEntityName - the JPA name of the entity

sEntityClassName - the fully-qualified class name of the entity

sUnitName - the name of the persistence unit

JpaCacheLoader

public JpaCacheLoader(java.lang.String sEntityName,
                      java.lang.String sEntityClassName,
                      java.lang.String sUnitName,
                      java.lang.ClassLoader loader)

Constructor which accepts an entity name, class name, persistence unit name, and classloader.

Parameters:

sEntityName - the JPA name of the entity

sEntityClassName - the fully-qualified class name of the entity

sUnitName - the name of the persistence unit

loader - the ClassLoader used to load the entity class

Method Detail

load

public java.lang.Object load(java.lang.Object oKey)

Return the value associated with the specified key, or null if the key does not have an associated value in the underlying store.

Specified by:

load in interface CacheLoader

Parameters:

oKey - key whose associated value is to be returned

Returns:

the value associated with the specified key, or null if no value is available for that key

loadAll

public java.util.Map loadAll(java.util.Collection colKeys)

Return the values associated with each the specified keys in the passed collection. If a key does not have an associated value in the underlying store, then the return map will not have an entry for that key.

Specified by:

loadAll in interface CacheLoader

Parameters:

colKeys - a collection of keys to load

Returns:

a Map of keys to associated values for the specified keys

initialize

protected void initialize(java.lang.String sEntityName,
                          java.lang.String sEntityClassName,
                          java.lang.String sUnitName,
                          java.lang.ClassLoader loader)

Initialize this instance with the relevant metadata for the entity being stored.

Parameters:

sEntityName - the JPA name of the entity

sEntityClassName - the fully-qualified class name of the entity

sUnitName - the name of the persistence unit

loader - the ClassLoader used to load the entity class

getEntityManager

protected javax.persistence.EntityManager getEntityManager()

Creates and returns an EntityManager. A new instance is created each time this method is called.

Returns:

a new EntityManager to use for a subsequent operation

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