/* 
 * Copyright (c) 2008 Stiftung Deutsches Elektronen-Synchrotron, 
 * Member of the Helmholtz Association, (DESY), HAMBURG, GERMANY.
 *
 * THIS SOFTWARE IS PROVIDED UNDER THIS LICENSE ON AN "../AS IS" BASIS. 
 * WITHOUT WARRANTY OF ANY KIND, EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED 
 * TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR PARTICULAR PURPOSE AND 
 * NON-INFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE 
 * FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR 
 * THE USE OR OTHER DEALINGS IN THE SOFTWARE. SHOULD THE SOFTWARE PROVE DEFECTIVE 
 * IN ANY RESPECT, THE USER ASSUMES THE COST OF ANY NECESSARY SERVICING, REPAIR OR 
 * CORRECTION. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS LICENSE. 
 * NO USE OF ANY SOFTWARE IS AUTHORIZED HEREUNDER EXCEPT UNDER THIS DISCLAIMER.
 * DESY HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, 
 * OR MODIFICATIONS.
 * THE FULL LICENSE SPECIFYING FOR THE SOFTWARE THE REDISTRIBUTION, MODIFICATION, 
 * USAGE AND OTHER RIGHTS AND OBLIGATIONS IS INCLUDED WITH THE DISTRIBUTION OF THIS 
 * PROJECT IN THE FILE LICENSE.HTML. IF THE LICENSE IS NOT INCLUDED YOU MAY FIND A COPY 
 * AT HTTP://WWW.DESY.DE/LEGAL/LICENSE.HTM
 */
 package org.csstudio.sds.ui.internal.layers;

import org.csstudio.sds.internal.model.Layer;
import org.csstudio.sds.internal.model.LayerSupport;
import org.eclipse.gef.commands.Command;

/**
 * A Command to move a Layer.
 * 
 * @author Kai Meyer
 */
public final class MoveLayerCommand extends Command {
	
	/**
	 * Access object to the layer model.
	 */
	private LayerSupport _layerSupport;

	/**
	 * The layer that is removed.
	 */
	private Layer _layer;

	/**
	 * The former index position of the removed layer.
	 */
	private int _oldIndex;
	
	/**
	 * The new index position of the removed layer.
	 */
	private int _newIndex;
	
	/**
	 * Constructor.
	 * 
	 * @param layerSupport
	 *            access object to the layer model
	 * @param layer
	 *            the layer that is about to be removed
	 * @param newIndex
	 * 			  the new index for the layer
	 */
	public MoveLayerCommand(final LayerSupport layerSupport, final Layer layer, final int newIndex) {
		assert layerSupport != null;
		assert layer != null;
		setLabel("Move Layer '"+layer.getDescription()+"'");
		_layerSupport = layerSupport;
		_layer = layer;
		_newIndex = newIndex;
	}
	
	/**
	 * {@inheritDoc}
	 */
	@Override
	public void execute() {
		_oldIndex = _layerSupport.getLayerIndex(_layer);
		_layerSupport.changeLayerPosition(_layer, _newIndex);
	}
	
	/**
	 * {@inheritDoc}
	 */
	@Override
	public void undo() {
		_layerSupport.changeLayerPosition(_layer, _oldIndex);
	}

}