oracle.toplink.essentials.internal.indirection.BackupValueHolder Maven / Gradle / Ivy
/*
* The contents of this file are subject to the terms
* of the Common Development and Distribution License
* (the "License"). You may not use this file except
* in compliance with the License.
*
* You can obtain a copy of the license at
* glassfish/bootstrap/legal/CDDLv1.0.txt or
* https://glassfish.dev.java.net/public/CDDLv1.0.html.
* See the License for the specific language governing
* permissions and limitations under the License.
*
* When distributing Covered Code, include this CDDL
* HEADER in each file and include the License file at
* glassfish/bootstrap/legal/CDDLv1.0.txt. If applicable,
* add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your
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*/
// Copyright (c) 1998, 2007, Oracle. All rights reserved.
package oracle.toplink.essentials.internal.indirection;
import oracle.toplink.essentials.indirection.*;
/**
* Used as the backup value holder in the unit of work for transparent indirection.
* This ensure that a reference to the original value holder is held in case the
* transparent collection or proxy is replace without first instantiating the original.
*
* @since 10.1.3
* @author James Sutherland
*/
public class BackupValueHolder extends ValueHolder {
/** Stores the original uow clone's value holder. */
protected ValueHolderInterface unitOfWorkValueHolder;
public BackupValueHolder(ValueHolderInterface unitOfWorkValueHolder) {
this.unitOfWorkValueHolder = unitOfWorkValueHolder;
}
/**
* If the original value holder was not instantiated,
* then first instantiate it to obtain the backup value.
*/
public Object getValue() {
// Ensures instantiation of the original, and setting of this back value holder's value.
getUnitOfWorkValueHolder().getValue();
return value;
}
/**
* Return the original uow clone's value holder.
*/
public ValueHolderInterface getUnitOfWorkValueHolder() {
return unitOfWorkValueHolder;
}
}