/*******************************************************************************
 * Copyright (c) 2004 Actuate Corporation.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *  Actuate Corporation  - initial API and implementation
 *******************************************************************************/

package org.eclipse.birt.report.model.command;

import org.eclipse.birt.report.model.activity.SimpleRecord;
import org.eclipse.birt.report.model.api.activity.NotificationEvent;
import org.eclipse.birt.report.model.api.command.ExtendsEvent;
import org.eclipse.birt.report.model.core.DesignElement;
import org.eclipse.birt.report.model.i18n.MessageConstants;
import org.eclipse.birt.report.model.i18n.ModelMessages;
import org.eclipse.birt.report.model.metadata.ElementRefValue;

/**
 * Sets the extends attribute of an element.
 * 
 */

public class ExtendsRecord extends SimpleRecord
{

	/**
	 * The element to modify.
	 */

	private DesignElement element = null;

	/**
	 * The new parent element. Can be null.
	 */

	protected ElementRefValue newParent = null;

	/**
	 * The old parent element. Can be null.
	 */

	private DesignElement oldParent = null;

	/**
	 * The old parent element name, if the name was unresolved.
	 */

	private String oldName = null;

	/**
	 * Constructor.
	 * 
	 * @param obj
	 *            the element to modify.
	 * @param parent
	 *            the new parent element.
	 */

	// public ExtendsRecord( DesignElement obj, DesignElement parent )
	// {
	// element = obj;
	// newParent = parent;
	// oldParent = obj.getExtendsElement( );
	// if ( oldParent == null )
	// oldName = obj.getExtendsName( );
	//
	// assert element != null;
	// assert parent == null || parent.getDefn( ) == element.getDefn( );
	// assert parent == null || !parent.isKindOf( element );
	//
	// label = ModelMessages.getMessage( MessageConstants.SET_EXTENDS_MESSAGE );
	//
	// }
	/**
	 * Constructor.
	 * 
	 * @param obj
	 *            the element to modify.
	 * @param parent
	 *            the style to set.
	 */

	public ExtendsRecord( DesignElement obj, ElementRefValue parent )
	{
		assert obj != null;

		element = obj;
		newParent = parent;
		oldParent = obj.getExtendsElement( );
		if ( oldParent == null )
			oldName = obj.getExtendsName( );

		label = ModelMessages.getMessage( MessageConstants.SET_EXTENDS_MESSAGE );

	}

	/**
	 * @see org.eclipse.birt.report.model.activity.SimpleRecord#perform(boolean)
	 */

	protected void perform( boolean undo )
	{
		if ( undo )
		{
			if ( oldName != null )
				element.setExtendsName( oldName );
			else
				element.setExtendsElement( oldParent );
		}
		else
		{
			DesignElement parent = newParent == null ? null : newParent
					.getElement( );
			element.setExtendsElement( parent );
		}
	}

	/**
	 * @see org.eclipse.birt.report.model.activity.AbstractElementRecord#getTarget()
	 */

	public DesignElement getTarget( )
	{
		return element;
	}

	/**
	 * @see org.eclipse.birt.report.model.activity.AbstractElementRecord#getEvent()
	 */

	public NotificationEvent getEvent( )
	{
		return new ExtendsEvent( element );
	}

}