simpleentitybean.java

老外的在线考试

/*
 * Core - Library of useful classes that are used in many CyberDemia projects.
 * Copyright (C) 2004 CyberDemia Research and Services
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA  02111-1307, USA.
 *
 * See the COPYING file located in the top-level-directory of
 * the archive of this library for complete text of license.
 */
package com.cyberdemia.ejb;

/**
 * SimpleEntityBean is an abstract base class for a majority of entity EJBs that
 * require some common fields such as id and name.
 * It has a primary key field named "id" of type Integer that is meant to
 * be auto-incremented by the app server/database. Hence the method
 * <code>getGeneratedPrimaryKey()</code> is provided to retrieve the
 * auto-generated key immediately after creating the bean.
 *
 * @ejb.bean name="SimpleEntityBean"
 *           generate="false"
 *           type="CMP"
 *           view-type="local"
 *
 * @ejb.pk class="java.lang.Integer"
 * @jboss.unknown-pk class="java.lang.Integer" auto-increment="true" jdbc-type="INTEGER" sql-type="INTEGER"
 * @jboss.entity-command name="mysql-get-generated-keys"
 *
 * @author Alexander Yap
 * @version $Revision: 1.1 $ at $Date: 2004/06/20 10:17:20 $ by $Author: alexycyap $
 */
public abstract class SimpleEntityBean extends BaseEntityBean
{

	/**
	* Gets the unique Id for this entity.
	*
	* @ejb.persistence read-only="true"
	* @ejb.pk-field
	* @ejb.interface-method
	* @jboss.persistence auto-increment="true"
	*
	* @return Unique Id
	*/
	public abstract Integer getId();

	/**
	* Sets the unique Id for this entity.
	* This method is never used.
	* @param id Unique Id
	*/
	public abstract void setId(Integer id);

	/**
	* Gets the display name for this entity.
	*
	* @ejb.interface-method
	* @ejb.persistence
	* @jboss.persistence not-null="true" dbindex="true"
	*
	* @return Display name
	*/
	public abstract String getName();

	/**
	* Sets the display name lookup key for this entity.
	*
	* @ejb.interface-method
	*
	* @param name Display name
	*/
	public abstract void setName(String name);

	/**
	* Gets the creation datetime of the entity in milliseconds.
	* This field is purely to track when this entity was created,
	* and should be set in ejbCreate.
	*
	* @ejb.interface-method
	* @ejb.persistence
	*
	* @return Create date
	*/
	public abstract long getCreatedMillis();

	/**
	* Sets the creation datetime of the entity in milliseconds.
	* This field is purely to track when this entity was created,
	* and should be set in ejbCreate.
	* @param created Creation datetime in milliseconds
	*/
	public abstract void setCreatedMillis(long created);

	/**
	* Gets the auto-generated primary key (field "id").
	* Useful to retrieve the primary key immediately after
	* creating the bean, when <code>getId()</code> would return null.
	* This method will convert the primary key to an Integer,
	* which is the type of the "id" field.
	*
	* @ejb.interface-method
	*
	* @return Primary key
	*/
	public Integer getGeneratedPrimaryKey()
	{
		Object pk = getEntityContext().getPrimaryKey();
		if (pk instanceof Integer)
		{
			return (Integer)pk;
		}

		if (pk instanceof Number)
		{
			return new Integer(((Number)pk).intValue());
		}

		return new Integer( pk.toString() );
	}

}