/* 
 * 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;

/**
 * Command that adds a layer.
 * 
 * @author swende
 * 
 */
final class AddLayerCommand extends Command {
	/**
	 * Access object to the layer model.
	 */
	private LayerSupport _layerSupport;

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

	/**
	 * The index position of the added layer.
	 */
	private int _index;

	/**
	 * Constructor.
	 * 
	 * @param layerSupport
	 *            acces object to the layer model
	 * @param layer
	 *            the layer that is about to be added
	 * @param index
	 *            the index position of the added layer
	 */
	public AddLayerCommand(final LayerSupport layerSupport, final Layer layer,
			final int index) {
		assert layerSupport != null;
		assert layer != null;
		setLabel("Add Layer");
		_layerSupport = layerSupport;
		_layer = layer;
		_index = index;
	}

	/**
	 * Constructor.
	 * 
	 * @param layerSupport
	 *            acces object to the layer model
	 * @param layer
	 *            the layer that is about to be added
	 */
	public AddLayerCommand(final LayerSupport layerSupport, final Layer layer) {
		assert layerSupport != null;
		assert layer != null;
		_layerSupport = layerSupport;
		_layer = layer;
		_index = -1;
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public void execute() {
		if (_index > -1) {
			_layerSupport.addLayer(_layer, _index);
		} else {
			_layerSupport.addLayer(_layer);
		}
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public void undo() {
		_layerSupport.removeLayer(_layer);
	}

}