ModelEndpointReferenceComponentEditPolicy.java

/*
 * Copyright (c) 2012-2016 Marsha Chechik, Alessio Di Sandro, Michalis Famelis,
 * Rick Salay.
 * 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:
 *    Alessio Di Sandro - Implementation.
 */
package edu.toronto.cs.se.mmint.mid.relationship.diagram.edit.policies;

import org.eclipse.gef.Request;
import org.eclipse.gef.commands.Command;
import org.eclipse.gmf.runtime.diagram.ui.editpolicies.ComponentEditPolicy;
import org.eclipse.gmf.runtime.diagram.ui.requests.GroupRequestViaKeyboard;
import org.eclipse.gmf.runtime.notation.View;

import edu.toronto.cs.se.mmint.mid.relationship.BinaryModelRel;
import edu.toronto.cs.se.mmint.mid.relationship.ModelEndpointReference;
import edu.toronto.cs.se.mmint.mid.relationship.diagram.edit.parts.ModelEndpointReferenceEditPart;

/**
 * The component edit policy for model references.
 * 
 * @author Alessio Di Sandro
 * 
 */
public class ModelEndpointReferenceComponentEditPolicy extends ComponentEditPolicy {

	/**
	 * Gets the command to delete a model reference when "Del" keyboard button
	 * is pressed.
	 * 
	 * @param request
	 *            The request.
	 * @return The executable command.
	 */
	@Override
	public Command getCommand(Request request) {

		if (request instanceof GroupRequestViaKeyboard) {

			ModelEndpointReferenceEditPart editPart = (ModelEndpointReferenceEditPart) getHost();
			ModelEndpointReference modelEndpointRef = (ModelEndpointReference) ((View) editPart.getModel()).getElement();
			if (modelEndpointRef.getContainedObject() == null && modelEndpointRef.eContainer() instanceof BinaryModelRel) {
				// a binary model relationship which is not standalone can be only modified through the Mid diagram
				return null;
			}
		}

		return super.getCommand(request);
	}

}