/******************************************************************************* | |
* Copyright (c) 1998, 2013 Oracle and/or its affiliates. All rights reserved. | |
* This program and the accompanying materials are made available under the | |
* terms of the Eclipse Public License v1.0 and Eclipse Distribution License v. 1.0 | |
* which accompanies this distribution. | |
* The Eclipse Public License is available at http://www.eclipse.org/legal/epl-v10.html | |
* and the Eclipse Distribution License is available at | |
* http://www.eclipse.org/org/documents/edl-v10.php. | |
* | |
* Contributors: | |
* Oracle - initial API and implementation from Oracle TopLink | |
******************************************************************************/ | |
package org.eclipse.persistence.internal.identitymaps; | |
import java.lang.ref.*; | |
/** | |
* <p><b>Purpose</b>: Container class for storing objects in an IdentityMap. | |
* The weak cache key uses a weak reference to allow garbage collection of its object. | |
* The cache key itself however will remain and thus should cleaned up every now and then. | |
* <p><b>Responsibilities</b>:<ul> | |
* <li> Hold key and object. | |
* <li> Maintain and update the current writeLockValue. | |
* </ul> | |
* @since TOPLink/Java 1.0 | |
*/ | |
public class WeakCacheKey extends CacheKey { | |
/** Reference is maintained weak to allow garbage collection */ | |
protected Reference reference; | |
/** | |
* Initialize the newly allocated instance of this class. | |
* @param primaryKey contains values extracted from the object | |
* @param writeLockValue is the write lock value, null if optimistic locking not being used for this object. | |
* @param readTime the time EclipseLInk read the cache key | |
*/ | |
public WeakCacheKey(Object primaryKey, Object object, Object writeLockValue, long readTime, boolean isIsolated) { | |
super(primaryKey, object, writeLockValue, readTime, isIsolated); | |
} | |
public Object getObject() { | |
if (this.reference == null) { | |
return null; | |
} | |
return this.reference.get(); | |
} | |
public void setObject(Object object) { | |
this.reference = new WeakReference(object); | |
} | |
} |