/* 
 * 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;
import org.eclipse.jface.action.IAction;

/**
 * Action that moves a layer down.
 * 
 * @author swende
 * 
 */
public final class MoveLayerDownAction extends AbstractLayerAction {

	/**
	 * {@inheritDoc}
	 */
	@Override
	protected void selectedLayerChanged(final Layer layer, final LayerSupport layerSupport, final IAction action) {
		action.setEnabled(layerSupport.getLayerIndex(layer)!=
				layerSupport.getLayers().size()-1);
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	protected Command createCommand(final Layer selectedLayer,
			final LayerSupport layerSupport, final IAction action) {

		Command result = null;

		if (selectedLayer != null && layerSupport != null) {
			int oldIndex = layerSupport.getLayerIndex(selectedLayer);
			int layerCount = layerSupport.getLayers().size();

			if (oldIndex <= layerCount - 2) {
				result = new MoveLayerCommand(layerSupport, selectedLayer, oldIndex + 1);
			}
		}

		return result;
	}

}