OwnedLinksNotationModelRefresher.java example

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/**
 * Copyright (c) 2006 Borland Software Corporation
 * 
 * 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:
 *    bblajer - initial API and implementation
 */
package org.eclipse.gmf.runtime.lite.edit.parts.update.canonical;

import java.util.HashMap;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

import org.eclipse.emf.common.command.Command;
import org.eclipse.emf.common.command.CompoundCommand;
import org.eclipse.emf.ecore.EObject;
import org.eclipse.gmf.runtime.lite.commands.CreateNotationalElementCommand;
import org.eclipse.gmf.runtime.lite.commands.ReconnectNotationalEdgeSourceCommand;
import org.eclipse.gmf.runtime.lite.commands.ReconnectNotationalEdgeTargetCommand;
import org.eclipse.gmf.runtime.lite.commands.RemoveNotationalEdgeCommand;
import org.eclipse.gmf.runtime.lite.commands.ReplaceNotationalElementCommand;
import org.eclipse.gmf.runtime.notation.Diagram;
import org.eclipse.gmf.runtime.notation.Edge;
import org.eclipse.gmf.runtime.notation.View;


public abstract class OwnedLinksNotationModelRefresher extends AbstractNotationModelRefresher {
	private final IViewService myViewService;

	public OwnedLinksNotationModelRefresher(IViewService viewService) {
		myViewService = viewService;
	}

	public Command buildRefreshNotationModelCommand() {
		List/*<LinkDescriptor>*/ semanticChildLinks = getSemanticChildLinks();
		List/*<Edge>*/ notationalChildLinks = getNotationalChildLinks();
		if (semanticChildLinks.isEmpty() && notationalChildLinks.isEmpty()) {
			return null;
		}
		final Map semanticToNotationalTypeBasedLinks = new HashMap();
		final Map/*<EObject, List<Edge>>*/ semanticToNotationalFeatureBasedLinks = new HashMap();
		for(Iterator it = notationalChildLinks.iterator(); it.hasNext(); ) {
			Edge next = (Edge) it.next();
			EObject nextSemantic = next.getElement();
			if (nextSemantic != null) {
				semanticToNotationalTypeBasedLinks.put(nextSemantic, next);
			} else {
				List featureBasedLinksForSource = (List) semanticToNotationalFeatureBasedLinks.get(next.getSource().getElement());
				if (featureBasedLinksForSource == null) {
					featureBasedLinksForSource = new LinkedList();
					semanticToNotationalFeatureBasedLinks.put(next.getSource().getElement(), featureBasedLinksForSource);
				}
				featureBasedLinksForSource.add(next);
			}
		}
		Diagram parentView = getHost().getDiagram();
		CompoundCommand command = new CompoundCommand();
		for(Iterator it = semanticChildLinks.iterator(); it.hasNext(); ) {
			LinkDescriptor next = (LinkDescriptor) it.next();
			EObject nextLinkElement = next.getElement();
			Edge currentEdge;
			if (nextLinkElement != null) {
				currentEdge = (Edge) semanticToNotationalTypeBasedLinks.remove(nextLinkElement);
			} else {
				List featureBasedLinksForSource = (List) semanticToNotationalFeatureBasedLinks.get(next.getSource());
				if (featureBasedLinksForSource == null || featureBasedLinksForSource.isEmpty()) {
					currentEdge = null;
				} else {
					currentEdge = (Edge) featureBasedLinksForSource.remove(0);
				}
			}
			int linkVisualID = next.getVisualID();
			if (currentEdge == null) {
				if (nextLinkElement == null || shouldCreateView(next)) {
					command.appendIfCanExecute(getCreateNotationalElementCommand(next));
				}
			} else {
				boolean changedSource = currentEdge.getSource().getElement() != next.getSource();
				boolean changedTarget = currentEdge.getTarget().getElement() != next.getDestination();
				boolean changedVID = linkVisualID != getVisualID(currentEdge);
				if (!changedSource && !changedTarget) {
					if (changedVID) {
						CreateNotationalElementCommand notationalCommand = getCreateNotationalElementCommand(next);
						if (notationalCommand != null) {
							command.appendIfCanExecute(new ReplaceNotationalElementCommand(parentView, notationalCommand, currentEdge));
						} else {
							command.appendIfCanExecute(new RemoveNotationalEdgeCommand(parentView, currentEdge));
						}
					}
				} else {
					if (changedVID) {
						command.appendIfCanExecute(new RemoveNotationalEdgeCommand(parentView, currentEdge));
						command.appendIfCanExecute(getCreateNotationalElementCommand(next));
					} else {
						View newSourceView = myViewService.findView(next.getSource());
						if (changedSource) {
							if (newSourceView != null && isValidLinkSource(newSourceView, next)) { 
								command.appendIfCanExecute(new ReconnectNotationalEdgeSourceCommand(currentEdge, newSourceView));
							} else {
								command.appendIfCanExecute(new RemoveNotationalEdgeCommand(currentEdge.getDiagram(), currentEdge));
							}
						}
						View newTargetView = myViewService.findView(next.getDestination());
						if (changedTarget) {
							if (newTargetView != null && isValidLinkTarget(newTargetView, next)) {
								command.appendIfCanExecute(new ReconnectNotationalEdgeTargetCommand(currentEdge, newTargetView));
							} else {
								command.appendIfCanExecute(new RemoveNotationalEdgeCommand(currentEdge.getDiagram(), currentEdge));
							}
						}
					}
				}
			}
		}
		for(Iterator it = semanticToNotationalTypeBasedLinks.values().iterator(); it.hasNext(); ) {
			View obsoleteView = (View) it.next();
			command.appendIfCanExecute(new RemoveNotationalEdgeCommand(parentView, obsoleteView));
		}
		for(Iterator it = semanticToNotationalFeatureBasedLinks.values().iterator(); it.hasNext(); ) {
			List obsoleteViews = (List) it.next();
			for(Iterator obsoleteViewsIt = obsoleteViews.iterator(); obsoleteViewsIt.hasNext(); ) {
				View obsoleteView = (View) obsoleteViewsIt.next();
				command.appendIfCanExecute(new RemoveNotationalEdgeCommand(parentView, obsoleteView));
			}
		}
		return command.getCommandList().isEmpty() ? null : command;
	}

	protected abstract List/*<LinkDescriptor>*/ getSemanticChildLinks();
	protected abstract List/*<Edge>*/ getNotationalChildLinks();

	/**
	 * Returns whether the given view can be source of the given link. 
	 */
	protected boolean isValidLinkSource(View sourceCandidate, LinkDescriptor linkDescriptor) {
		return true;
	}

	/**
	 * Returns whether the given view can be source of the given link. 
	 */
	protected boolean isValidLinkTarget(View targetCandidate, LinkDescriptor linkDescriptor) {
		return true;
	}
}