/* $Id: DiagramUndoManager.java 17850 2010-01-12 19:53:35Z linus $

  *****************************************************************************

  * Copyright (c) 2009 Contributors - see below

  * 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:

  *    mvw

  *****************************************************************************

  *

  * Some portions of this file was previously release using the BSD License:

  */

 // Copyright (c) 2007-2008 The Regents of the University of California. All

 // Rights Reserved. Permission to use, copy, modify, and distribute this

 // software and its documentation without fee, and without a written

 // agreement is hereby granted, provided that the above copyright notice

 // and this paragraph appear in all copies. This software program and

 // documentation are copyrighted by The Regents of the University of

 // California. The software program and documentation are supplied "AS

 // IS", without any accompanying services from The Regents. The Regents

 // does not warrant that the operation of the program will be

 // uninterrupted or error-free. The end-user understands that the program

 // was developed for research purposes and is advised not to rely

 // exclusively on the program for any reason. IN NO EVENT SHALL THE

 // UNIVERSITY OF CALIFORNIA BE LIABLE TO ANY PARTY FOR DIRECT, INDIRECT,

 // SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS,

 // ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN IF

 // THE UNIVERSITY OF CALIFORNIA HAS BEEN ADVISED OF THE POSSIBILITY OF

 // SUCH DAMAGE. THE UNIVERSITY OF CALIFORNIA SPECIFICALLY DISCLAIMS ANY

 // WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF

 // MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE

 // PROVIDED HEREUNDER IS ON AN "AS IS" BASIS, AND THE UNIVERSITY OF

 // CALIFORNIA HAS NO OBLIGATIONS TO PROVIDE MAINTENANCE, SUPPORT,

 // UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 package org.argouml.uml.diagram;

 import java.beans.PropertyChangeListener;

 import org.apache.log4j.Logger;

 import org.argouml.kernel.Project;

 import org.argouml.kernel.ProjectManager;

 import org.tigris.gef.undo.Memento;

 import org.tigris.gef.undo.UndoManager;

 /**

  * This class is a temporary wrapper around the GEF UndoManager.

  * This will be changed when GEF is modified to create commands and

  * provide an observer interface for ArgoUML to receive them.

  * <p>

  * TODO: How does this relate to {@link org.argouml.kernel.DefaultUndoManager}?

  * 

  * @author Bob Tarling

  */

 public class DiagramUndoManager extends UndoManager {

     private static final Logger LOG = Logger.getLogger(UndoManager.class);

     private boolean startChain;

     /**

      * Called when a new user interaction starts

      * @see org.tigris.gef.undo.UndoManager#startChain()

      */

     @Override

     public void startChain() {

         startChain = true;

     }

     @Override

     public boolean isGenerateMementos() {

         // TODO: This shouldn't depend on the current project, but for now

         // just make sure it's defined and that we have an undo manager

         Project p = ProjectManager.getManager().getCurrentProject();

         return super.isGenerateMementos() && p != null 

                 && p.getUndoManager() != null;

     }

     /**

      * @param memento the GEF memento

      * @see org.tigris.gef.undo.UndoManager#addMemento(org.tigris.gef.undo.Memento)

      */

     @Override

     public void addMemento(final Memento memento) {

         // TODO: This shouldn't be referencing the current project.  Instead

         // the appropriate UndoManager should have already been retrieved from

         // the correct project.

         Project p = ProjectManager.getManager().getCurrentProject();

         if (p != null) {

             org.argouml.kernel.UndoManager undo = p.getUndoManager();

             if (undo != null) {

                 if (startChain) {

                     //TODO i18n: GEF needs to pass us back the description

                     // of what is being done.

                     undo.startInteraction("Diagram Interaction");

                 }

                 // TODO: I presume this would fix issue 5250 - but

                 // GEF would need to be adapted:

 //                if (!(memento instanceof SelectionMemento))  

                 undo.addCommand(new DiagramCommand(memento));

                 startChain = false;

             }

         }

     }

     public void addPropertyChangeListener(PropertyChangeListener listener) {

         LOG.info("Adding property listener " + listener);

         super.addPropertyChangeListener(listener);

     }

     private class DiagramCommand

             extends org.argouml.kernel.AbstractCommand {

         private final Memento memento;

         DiagramCommand(final Memento theMemento) {

             this.memento = theMemento;

         }

         @Override

         public Object execute() {

             memento.redo();

             return null;

         }

         @Override

         public void undo() {

             memento.undo();

         }

         @Override

         public String toString() {

             return memento.toString();

         }

     }

 }