| /* |
| * Copyright (c) 1998, 2020 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 v. 2.0 which is available at |
| * http://www.eclipse.org/legal/epl-2.0, |
| * or the Eclipse Distribution License v. 1.0 which is available at |
| * http://www.eclipse.org/org/documents/edl-v10.php. |
| * |
| * SPDX-License-Identifier: EPL-2.0 OR BSD-3-Clause |
| */ |
| |
| // 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); |
| } |
| |
| @Override |
| public Object getObject() { |
| if (this.reference == null) { |
| return null; |
| } |
| return this.reference.get(); |
| } |
| |
| @Override |
| public void setObject(Object object) { |
| this.reference = new WeakReference(object); |
| } |
| } |