/*******************************************************************************
 * Copyright (c) 1998, 2008 Oracle. 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.annotations;

/** 
 * An enum that is used within the OptimisticLocking annotation.
 * 
 * @see org.eclipse.persistence.annotations.OptimisticLocking.
 * @author Guy Pelletier
 * @since Oracle TopLink 11.1.1.0.0 
 */ 
public enum OptimisticLockingType {
    /**
     * Using this type of locking policy compares every field in the table
     * in the WHERE clause when doing an update or a delete. If any field
     * has been changed, an optimistic locking exception will be thrown.
     */
    ALL_COLUMNS,

    /**
     * Using this type of locking policy compares only the changed fields
     * in the WHERE clause when doing an update. If any field has been
     * changed, an optimistic locking exception will be thrown. A delete
     * will only compare the primary key.
     */
    CHANGED_COLUMNS,

    /**
     * Using this type of locking compares selected fields in the WHERE
     * clause when doing an update or a delete. If any field has been
     * changed, an optimistic locking exception will be thrown. Note that
     * the fields specified must be mapped and not be primary keys.
     */
    SELECTED_COLUMNS,

    /**
     * Using this type of locking policy compares a single version number
     * in the where clause when doing an update. The version field must be
     * mapped and not be the primary key.
     */
    VERSION_COLUMN
}

