/* Copyright 2004, 2005, 2006 Acegi Technology Pty Limited
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.acegisecurity.domain.impl;

import org.acegisecurity.domain.PersistableEntity;


/**
 * An abstract implementation of {@link org.acegisecurity.domain.PersistableEntity}.
 *
 * @author Ben Alex
 * @version $Id$
 */
public abstract class AbstractPersistableEntity extends BusinessObject implements PersistableEntity {
    //~ Static fields/initializers =====================================================================================

    public static final int STARTING_VERSION = 0;

    //~ Instance fields ================================================================================================

    private int version = STARTING_VERSION;

    //~ Methods ========================================================================================================

    /**
     * Returns the version number, which should be managed by the persistence layer.<p>Initially all
     * <code>PersistableEntity</code>s will commence with the version number defined by {@link #STARTING_VERSION}.</p>
     *
     * @return the version
     */
    public int getVersion() {
        return version;
    }

    /**
     * Indicates whether this persistable entity has been persisted yet. Determine based on whether the {@link
     * #getInternalId()} returns <code>null</code> or a non-<code>null</code> value.
     *
     * @return <code>true</code> if the instance has not been persisted, <code>false</code> otherwise
     */
    public boolean isNew() {
        return (getInternalId() == null);
    }
}
