org.eclipse.persistence.descriptors.ClassExtractor Maven / Gradle / Ivy

Go to download

Show more of this group Show more artifacts with this name
Show all versions of eclipselink Show documentation

EclipseLink build based upon Git transaction f2b9fc5

There is a newer version: 5.0.0-B03

/*
 * 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.descriptors;

import org.eclipse.persistence.exceptions.*;
import org.eclipse.persistence.sessions.*;

/**
 * Purpose:
 * Abstract class to allow complex inheritance support.  Typically class indicators are used to define inheritance in the database,
 * however in complex cases the class type may be determined through another mechanism.
 * The class extractor must be able to determine and return the class type from the database row.
 *
 * @see org.eclipse.persistence.descriptors.InheritancePolicy#setClassExtractor(ClassExtractor)
 */
public abstract class ClassExtractor {

    /**
     * Extract/compute the class from the database row and return the class.
     * Map is used as the public interface to database row, the key is the field name,
     * the value is the database value.
     */
    public abstract Class extractClassFromRow(org.eclipse.persistence.sessions.Record databaseRow, Session session);

    /**
     * Allow for any initialization.
     */
    public void initialize(ClassDescriptor descriptor, Session session) throws DescriptorException {
        // Do nothing by default.
    }
}