org.eclipse.persistence.internal.indirection

Class TransformerBasedValueHolder

java.lang.Object

org.eclipse.persistence.internal.indirection.DatabaseValueHolder

org.eclipse.persistence.internal.indirection.TransformerBasedValueHolder

All Implemented Interfaces:

java.io.Serializable, java.lang.Cloneable, ValueHolderInterface, WeavedAttributeValueHolderInterface

public class TransformerBasedValueHolder
extends DatabaseValueHolder

Since:

release specific (what release of product did this appear in) This class is to replace the MethodBasedValueHolder for TransformationMappings Holds on to an AttributeTransformer and uses it to generate the attribute value when triggered. That Transformer may be a MethodBasedAttributeTransformer or a user defined implementation.

Version:

$Header: TransformerBasedValueHolder.java 30-aug-2006.11:32:36 gyorke Exp $

Author:

mmacivor

See Also:

Serialized Form

Field Summary

Fields inherited from interface org.eclipse.persistence.indirection.ValueHolderInterface

shouldToStringInstantiate

Constructor Summary

Constructors

Constructor and Description
TransformerBasedValueHolder(AttributeTransformer theTransformer, java.lang.Object theObject, AbstractRecord theRow, AbstractSession theSession) Initialize the method-based value holder.

Method Summary

Modifier and Type	Method and Description
java.lang.Object	instantiateForUnitOfWorkValueHolder(UnitOfWorkValueHolder unitOfWorkValueHolder) Triggers UnitOfWork valueholders directly without triggering the wrapped valueholder (this).
boolean	isPessimisticLockingValueHolder() INTERNAL: Answers if this valueholder is a pessimistic locking one.

Methods inherited from class org.eclipse.persistence.internal.indirection.DatabaseValueHolder

clone, getRow, getSession, getValue, getValue, getWrappedValueHolder, isCoordinatedWithProperty, isEasilyInstantiated, isInstantiated, isNewlyWeavedValueHolder, isSerializedRemoteUnitOfWorkValueHolder, postInstantiate, privilegedSetValue, releaseWrappedValueHolder, setInstantiated, setIsCoordinatedWithProperty, setIsNewlyWeavedValueHolder, setRow, setSession, setUninstantiated, setValue, shouldAllowInstantiationDeferral, toString

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Constructor Detail

TransformerBasedValueHolder

public TransformerBasedValueHolder(AttributeTransformer theTransformer,
                                   java.lang.Object theObject,
                                   AbstractRecord theRow,
                                   AbstractSession theSession)

Initialize the method-based value holder.

Parameters:

theMethod - The method that returns the object when executed.

object - the Object which owns this attribute.

theRow - The row representation of the object.

theSession - The session to the database that stores the object.

Method Detail

instantiateForUnitOfWorkValueHolder

public java.lang.Object instantiateForUnitOfWorkValueHolder(UnitOfWorkValueHolder unitOfWorkValueHolder)

Triggers UnitOfWork valueholders directly without triggering the wrapped valueholder (this).

When in transaction and/or for pessimistic locking the UnitOfWorkValueHolder needs to be triggered directly without triggering the wrapped valueholder. However only the wrapped valueholder knows how to trigger the indirection, i.e. it may be a batchValueHolder, and it stores all the info like the row and the query. Note: This method is not thread-safe. It must be used in a synchronized manner

Specified by:

instantiateForUnitOfWorkValueHolder in class DatabaseValueHolder

isPessimisticLockingValueHolder

public boolean isPessimisticLockingValueHolder()

INTERNAL: Answers if this valueholder is a pessimistic locking one. Such valueholders are special in that they can be triggered multiple times by different UnitsOfWork. Each time a lock query will be issued. Hence even if instantiated it may have to be instantiated again, and once instantiated all fields can not be reset. Note: This method is not thread-safe. It must be used in a synchronized manner

Specified by:

isPessimisticLockingValueHolder in class DatabaseValueHolder