plugins/diagram/org.eclipse.papyrus.sysml.diagram.internalblock/src/org/eclipse/papyrus/sysml/diagram/internalblock/utils/PortDropHelper.java

/*****************************************************************************
 * Copyright (c) 2011 CEA LIST.
 *
 * 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:
 *
 *		CEA LIST - Initial API and implementation
 *
 *****************************************************************************/
package org.eclipse.papyrus.sysml.diagram.internalblock.utils;

import org.eclipse.draw2d.geometry.Point;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.emf.transaction.TransactionalEditingDomain;
import org.eclipse.gef.commands.Command;
import org.eclipse.gef.commands.UnexecutableCommand;
import org.eclipse.gmf.runtime.common.core.command.ICommand;
import org.eclipse.gmf.runtime.diagram.core.util.ViewUtil;
import org.eclipse.gmf.runtime.diagram.ui.commands.CommandProxy;
import org.eclipse.gmf.runtime.diagram.ui.editparts.GraphicalEditPart;
import org.eclipse.gmf.runtime.diagram.ui.requests.CreateViewRequest;
import org.eclipse.gmf.runtime.diagram.ui.requests.CreateViewRequest.ViewDescriptor;
import org.eclipse.gmf.runtime.diagram.ui.requests.DropObjectsRequest;
import org.eclipse.gmf.runtime.emf.core.util.EObjectAdapter;
import org.eclipse.gmf.runtime.notation.Node;
import org.eclipse.gmf.runtime.notation.View;
import org.eclipse.papyrus.commands.wrappers.CommandProxyWithResult;
import org.eclipse.papyrus.infra.gmfdiag.common.utils.ViewDescriptorUtil;
import org.eclipse.papyrus.uml.diagram.common.helper.ElementHelper;
import org.eclipse.uml2.uml.Classifier;
import org.eclipse.uml2.uml.Port;
import org.eclipse.uml2.uml.Type;
import org.eclipse.uml2.uml.TypedElement;

/**
 * This class provides convenience methods to create Type specific drop action (Show Port on BlockPropertyComposite).
 */
public class PortDropHelper extends ElementHelper {

	public PortDropHelper(TransactionalEditingDomain editDomain) {
		this.editDomain = editDomain;
	}

	public ICommand getDropPortOnPart(DropObjectsRequest request, GraphicalEditPart host) {

		Object droppedEObject = request.getObjects().get(0);
		if (!isValidPort(droppedEObject, getHostEObject(host))) {
			return new CommandProxy(UnexecutableCommand.INSTANCE);
		}

		return getDropPortOnPart((Port) droppedEObject, request.getLocation().getCopy(), host);
	}

	public ICommand getDropPortOnPart(Port droppedPort, Point location, GraphicalEditPart host) {

		if (!isValidPort(droppedPort, getHostEObject(host))) {
			return new CommandProxy(UnexecutableCommand.INSTANCE);
		}

		// Prepare the view creation command
		ViewDescriptor descriptor = new ViewDescriptor(new EObjectAdapter(droppedPort), Node.class, /* explicit semantic hint is mandatory */null, ViewDescriptorUtil.PERSISTED, host.getDiagramPreferencesHint());
		CreateViewRequest createViewRequest = new CreateViewRequest(descriptor);
		createViewRequest.setLocation(location);
		Command viewCreateCommand = host.getCommand(createViewRequest);

		return new CommandProxyWithResult(viewCreateCommand, descriptor);
	}

	private boolean isValidPort(Object object, EObject dropTarget) {
		boolean isValid = false;

		// The drop object is supposed to be a Port (or FlowPort)
		if ((object != null) && (object instanceof Port)) {

			Port port = (Port) object;
			// The dropTarget has to be a TypedElement with a non-null Type
			if ((dropTarget != null) && (dropTarget instanceof TypedElement) && (((TypedElement) dropTarget).getType() != null)) {

				Type targetType = ((TypedElement) dropTarget).getType();
				// The dropped object is owned by the target type

				if (targetType instanceof Classifier) {
					Classifier classifier = (Classifier) targetType;
					isValid = classifier.getAllAttributes().contains(port);
				}
			}
		}

		return isValid;
	}

	/**
	 * return the host Edit Part's semantic element, if the semantic element
	 * is <code>null</code> or unresolvable it will return <code>null</code>
	 *
	 * @return EObject
	 */
	protected EObject getHostEObject(GraphicalEditPart host) {
		return ViewUtil.resolveSemanticElement((View) host.getModel());
	}
}