UserVersionType.java

/*
 * Hibernate, Relational Persistence for Idiomatic Java
 *
 * License: GNU Lesser General Public License (LGPL), version 2.1 or later.
 * See the lgpl.txt file in the root directory or <http://www.gnu.org/licenses/lgpl-2.1.html>.
 */
package org.hibernate.usertype;

import java.util.Comparator;

import org.hibernate.engine.spi.SharedSessionContractImplementor;

/**
 * A user type that may be used for a version property
 * 
 * @author Gavin King
 */
public interface UserVersionType extends UserType, Comparator {
	/**
	 * Generate an initial version.
	 *
	 * @param session The session from which this request originates.  May be
	 * null; currently this only happens during startup when trying to determine
	 * the "unsaved value" of entities.
	 * @return an instance of the type
	 */
	Object seed(SharedSessionContractImplementor session);

	/**
	 * Increment the version.
	 *
	 * @param session The session from which this request originates.
	 * @param current the current version
	 * @return an instance of the type
	 */
	Object next(Object current, SharedSessionContractImplementor session);

}