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com.tangosol.coherence.toplink
Class TopLinkCacheLoader

java.lang.Object
com.tangosol.util.Base
com.tangosol.coherence.toplink.TopLinkCacheLoader

All Implemented Interfaces:

CacheLoader

Direct Known Subclasses:

TopLinkCacheStore

public class TopLinkCacheLoader

extends Base

implements CacheLoader

TopLink implementation of the CacheLoader interface. <p/> Use this class as a load-only implementation that uses TopLink to load entities to and from a data store. The entities must be mapped to the data store and a TopLink session configuration or TopLink JPA persistence unit configuration must exist on the classpath. <p/> Use the TopLinkCacheStore class for a full load and store implementation.

Author:

mlk 2007.04.20, jh 2005.05.18

See Also:

TopLinkCacheStore

Field Summary

protected Class	m_clzEntity The entity class that this CacheLoader is managing.
protected oracle.toplink.essentials.descriptors.ClassDescriptor	m_descEntity Descriptor for entity class.
protected boolean	m_fUsePkClass Flag to indicate whether or not the PK is a composite class.
protected oracle.toplink.essentials.mappings.DatabaseMapping	m_mappingPk Database mapping of the PK attribute.
protected String	m_sEntityName Name of the entity that this CacheLoader is managing.
protected oracle.toplink.essentials.sessions.Session	m_session Shared session for all entities.
protected String	m_sPkField Field name of the PK attribute.

Constructor Summary

TopLinkCacheLoader(String sEntityName)
Constructor which accepts an entity name.

TopLinkCacheLoader(String sEntityName, String sSessionName)
Constructor which accepts an entity name and session name.

Method Summary

protected void	initialize(String sEntityName, String sSessionName) Initialize the instance with the relevant metadata for the entity being stored.
Object	load(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.
Map	loadAll(Collection colKeys) Return the values associated with each the specified keys in the passed collection.
protected Object	queryByPk(oracle.toplink.essentials.sessions.UnitOfWork uow, Object oKey) Internal method to create and execute a "findByPK" query.
protected Object	queryByPkCollection(oracle.toplink.essentials.sessions.UnitOfWork uow, Collection colPk) Internal method to create and execute a query to find in a group of PKs.

Field Detail

m_sEntityName

protected String m_sEntityName

Name of the entity that this CacheLoader is managing.

m_clzEntity

protected Class m_clzEntity

The entity class that this CacheLoader is managing.

m_fUsePkClass

protected boolean m_fUsePkClass

Flag to indicate whether or not the PK is a composite class.

m_mappingPk

protected oracle.toplink.essentials.mappings.DatabaseMapping m_mappingPk

Database mapping of the PK attribute.

m_sPkField

protected String m_sPkField

Field name of the PK attribute.

m_descEntity

protected oracle.toplink.essentials.descriptors.ClassDescriptor m_descEntity

Descriptor for entity class.

m_session

protected oracle.toplink.essentials.sessions.Session m_session

Shared session for all entities.

Constructor Detail

TopLinkCacheLoader

public TopLinkCacheLoader(String sEntityName)

Constructor which accepts an entity name.

Parameters:

sEntityName - the alias for the persistent class

TopLinkCacheLoader

public TopLinkCacheLoader(String sEntityName,
                          String sSessionName)

Constructor which accepts an entity name and session name.

Parameters:

sEntityName - the alias for the persistent class

sSessionName - the name of the TopLink session (usually defined in sessions.xml)

Method Detail

load

public Object load(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 Map loadAll(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(String sEntityName,
                          String sSessionName)

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

Parameters:

sEntityName - the alias for the persistent class

sSessionName - the name of the TopLink session

queryByPk

protected Object queryByPk(oracle.toplink.essentials.sessions.UnitOfWork uow,
                           Object oKey)

Internal method to create and execute a "findByPK" query.

Parameters:

uow - the unit of work to use for the operation; if null use the session

oKey - the primary key to use to find the object

Returns:

the found object, or null if not found

queryByPkCollection

protected Object queryByPkCollection(oracle.toplink.essentials.sessions.UnitOfWork uow,
                                     Collection colPk)

Internal method to create and execute a query to find in a group of PKs. <p/> This method assumes that the entity has a simple PK and not a PK class, and the Collection passed in is one of simple PK value objects. This method should not be used when the entity has a PK class.

Parameters:

uow - the unit of work to use for the operation; if null use the session

colPk - the Collection of primary keys to use to find the entity instances

Returns:

the Collection of entities with a PK matching any of the specified PKs

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