org.eclipse.persistence.internal.identitymaps.SoftIdentityMap Maven / Gradle / Ivy

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/*
 * 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 org.eclipse.persistence.descriptors.ClassDescriptor;
import org.eclipse.persistence.internal.sessions.AbstractSession;

/**
 * Purpose: A SoftIdentityMap holds all objects referenced by the application.
 * The soft identity map is similar to the weak identity map except for the fact that it allows
 * only garbage collects when memory is low.
 * 
Responsibilities:

 *  Guarantees identity.
 * 
 Allows garbage collection when memory is low.
 * 
 * @author James Sutherland
 * @since TopLink 11g
 */
public class SoftIdentityMap extends WeakIdentityMap {

    public SoftIdentityMap(int size, ClassDescriptor descriptor, AbstractSession session, boolean isIsolated) {
        super(size, descriptor, session, isIsolated);
        this.cleanupCount = 0;
        this.cleanupSize = size;
    }

    @Override
    public CacheKey createCacheKey(Object primaryKey, Object object, Object writeLockValue, long readTime) {
        return new SoftCacheKey(primaryKey, object, writeLockValue, readTime, isIsolated);
    }
}