plugins/org.eclipse.bpel.common.ui.noEmbeddedEditors/src/org/eclipse/bpel/common/ui/editmodel/EditModelCommandStack.java - bpel/org.eclipse.bpel - Git at Google

 /*******************************************************************************
  * Copyright (c) 2005 IBM Corporation and others.
  * 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:
  *     IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.bpel.common.ui.editmodel;

 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.EventObject;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Set;

 import org.eclipse.bpel.common.ui.CommonUIPlugin;
 import org.eclipse.bpel.common.ui.Messages;
 import org.eclipse.core.resources.IFile;
 import org.eclipse.core.resources.ResourcesPlugin;
 import org.eclipse.core.runtime.IStatus;
 import org.eclipse.emf.ecore.resource.Resource;
 import org.eclipse.gef.commands.Command;
 import org.eclipse.gef.commands.CommandStack;
 import org.eclipse.gef.commands.CommandStackListener;
 import org.eclipse.gef.commands.CompoundCommand;
 import org.eclipse.jface.dialogs.IDialogConstants;
 import org.eclipse.jface.dialogs.MessageDialog;
 import org.eclipse.osgi.util.NLS;
 import org.eclipse.swt.widgets.Shell;
 import org.eclipse.ui.IWorkbenchWindow;


 /**
  * Implements the CommandStack API, adds extra notifications,
  * supports validateEdit and update the resource's dirty state.
  *
  * WDG: TODO: the GEF CommandStack has been extended with extra notifications.
  * However, how are we supposed to use it since everything is still private?
  */
 public class EditModelCommandStack extends CommandStack {

 	protected int saveLocation = 0;
 	protected int fCurrentLocation = 0;

 	protected Set<Resource> dirtyUntilSave = new HashSet<Resource>();

 	protected List<Context> fContexts = new ArrayList<Context>(30);

 	/**
 	 * Brand new shiny EditModelCommandStack.
 	 */
 	public EditModelCommandStack() {
 		super();
 	}

 	/**
 	 * @see org.eclipse.gef.commands.CommandStack#getUndoCommand()
 	 */
 	@Override
 	public Command getUndoCommand() {
 		if (fCurrentLocation < 1) {
 			return null;
 		}
 		return fContexts.get(fCurrentLocation-1).fCommand;
 	}

 	/**
 	 * @see org.eclipse.gef.commands.CommandStack#canUndo()
 	 */
 	@Override
 	public boolean canUndo() {
 		Command c = getUndoCommand();
 		return (c != null) && c.canUndo();
 	}


 	/**
 	 * @see org.eclipse.gef.commands.CommandStack#getRedoCommand()
 	 */
 	@Override
 	public Command getRedoCommand() {
 		if (fCurrentLocation >= fContexts.size()) return null;
 		return fContexts.get(fCurrentLocation).fCommand;
 	}

 	/**
 	 * @see org.eclipse.gef.commands.CommandStack#canRedo()
 	 */
 	@Override
 	public boolean canRedo() {
 		return (getRedoCommand() != null);
 	}

 	/**
 	 * @see org.eclipse.gef.commands.CommandStack#execute(org.eclipse.gef.commands.Command)
 	 */
 	@Override
 	public void execute (Command command) {
 		SharedCommandStackChangedEvent event = notifyListeners(SharedCommandStackListener.EVENT_START_EXECUTE);
 		if (!event.doit) return;

 		if(getUndoCommand() instanceof PlaceHolderCommand) {
 			// This should never happen because the EditModelCommandFramework should
 			// remove the placeholder during the notifyListeners() call above.
 			throw new IllegalStateException();
 		}
 		if (command == null) return;
 		if (!validateEdit(command)) return;
 		if (!command.canExecute()) return;
 		drop(fCurrentLocation, fContexts.size());

 		// Paranoia check
 		if(getUndoCommand() instanceof PlaceHolderCommand) {
 			// This should never happen because the EditModelCommandFramework should
 			// remove the placeholder during the notifyListeners() call above.
 			throw new IllegalStateException();
 		}
 		command.execute();
 		if(getUndoCommand() instanceof PlaceHolderCommand) {
 			// This should never happen because the EditModelCommandFramework should
 			// remove the placeholder during the notifyListeners() call above.
 			throw new IllegalStateException();
 		}
 		int limit = getUndoLimit();
 		if (limit > 0) while (fCurrentLocation >= limit) {
 			if (saveLocation == 0) saveLocation = -1;
 			drop(0);
 			notifyListeners(SharedCommandStackListener.EVENT_DROP_LAST_UNDO_STACK_ENTRY);
 		}
 		if(getUndoCommand() instanceof PlaceHolderCommand) {
 			// This should never happen because the EditModelCommandFramework should
 			// remove the placeholder during the notifyListeners() call above.
 			throw new IllegalStateException();
 		}
 		Resource[] resources = getModifiedResources(command);
 		if ((resources.length > 0) || (command instanceof PlaceHolderCommand)) {
 			Context c = new Context(command, resources);
 			fContexts.add(c); fCurrentLocation = fContexts.size();
 			// mark resources as dirty/clean as appropriate.
 			c.setModifiedFlags(true);
 			//System.out.println("execute - markModified.  currentLocation="+currentLocation+", saveLocation="+saveLocation);
 		}
 		notifyListeners(SharedCommandStackListener.EVENT_FINISH_EXECUTE);
 	}
 	/*
 	 * call VCM validateEdit;
 	 * open the dialog to ask the user if he/she wants to procede
 	 * 		in case the file is readonly;
 	 * return true if the command should be executed otherwise returns false;
 	 */
 	protected boolean validateEdit(Command command) {
 		Resource[] resources = getResources(command);
 		if(resources.length == 0)
 			return true;
 		boolean disposeShell = false;
 		Shell shell;
 		IWorkbenchWindow win = CommonUIPlugin.getDefault().getWorkbench().getActiveWorkbenchWindow();
 		if (win != null) {
 			shell = win.getShell();
 		} else {
 			disposeShell = true;
 			shell = new Shell();
 		}
 		try {
 			IFile[] files = new IFile[resources.length];
 			StringBuffer filesString = new StringBuffer();
 			for (int i = 0; i < resources.length; i++) {
 				Resource resource = resources[i];
 				files[i] = EditModel.getIFileForURI(resource.getURI());
 				filesString.append(files[i].getName());
 				if(i < resources.length - 1)
 					filesString.append(", "); //$NON-NLS-1$
 			}
 			IStatus stat = ResourcesPlugin.getWorkspace().validateEdit(files, shell);
 			if (stat.getSeverity() == IStatus.CANCEL) {
 				return false;
 			} else if (!stat.isOK()) {
 				String[] buttons = { IDialogConstants.OK_LABEL }; //
 				String msg;
 				if(files.length == 1)
 					msg = NLS.bind(Messages.EditModelCommandStack_validateEdit_message0, (new String[]{filesString.toString(),stat.getMessage()}));
 				else
 					msg = NLS.bind(Messages.EditModelCommandStack_validateEdit_message1, (new String[]{filesString.toString(),stat.getMessage()}));
 				MessageDialog dialog = new MessageDialog(
 						shell,
 						Messages.EditModelCommandStack_validateEdit_title,
 						null, // accept the default windowing system icon
 						msg,
 						MessageDialog.WARNING,
 						buttons,
 						0);
 				dialog.open();
 				return false;
 			}
 		} finally {
 			if(disposeShell)
 				shell.dispose();
 		}
 		return true;
 	}

 	/**
 	 * @see org.eclipse.gef.commands.CommandStack#dispose()
 	 */
 	@Override
 	public void dispose() {
 		drop(0,fContexts.size());
 	}

 	/**
 	 * @see org.eclipse.gef.commands.CommandStack#flush()
 	 */
 	@Override
 	public void flush() {
 		SharedCommandStackChangedEvent event = notifyListeners(SharedCommandStackListener.EVENT_START_FLUSH);
 		if (!event.doit) return;

 		drop(0, fContexts.size());
 		fContexts.clear();
 		saveLocation = -1;
 		fCurrentLocation = 0;
 		// TODO: should we mark all resources as clean?
 		notifyListeners(SharedCommandStackListener.EVENT_FINISH_FLUSH);
 	}

 	/**
 	 * @see org.eclipse.gef.commands.CommandStack#getCommands()
 	 */
 	@Override
 	public Object[] getCommands() {
 		Object[] commands = new Object[fContexts.size()];
 		for (int i = 0; i < fContexts.size(); i++) {
 			commands[i] = fContexts.get(i).fCommand;
 		}
 		return commands;
 	}


 	/**
 	 * @see org.eclipse.gef.commands.CommandStack#isDirty()
 	 */
 	@Override
 	public boolean isDirty() {
 		//System.out.println("isDirty: C="+currentLocation+"  S="+saveLocation+"  dus="+dirtyUntilSave.size());
 		return (fCurrentLocation != saveLocation) || !dirtyUntilSave.isEmpty();
 	}

 	/**
 	 * @see org.eclipse.gef.commands.CommandStack#markSaveLocation()
 	 */
 	@Override
 	public void markSaveLocation() {
 //		// mark all the resources we know about as clean!
 //		for (int i = 0; i<contexts.size(); i++) {
 //			Context c = (Context)contexts.get(i);
 //			c.setModifiedFlags(false);
 //		}
 //		// that includes ones that fell off the bottom of the undo stack.
 //		for (Iterator it = dirtyUntilSave.iterator(); it.hasNext(); ) {
 //			setResourceModified((Resource)it.next(), false);
 //		}
 		dirtyUntilSave.clear();

 		saveLocation = fCurrentLocation;
 		notifyListeners(SharedCommandStackListener.EVENT_MARK_SAVED);
 	}

 	/**
 	 * @see org.eclipse.gef.commands.CommandStack#undo()
 	 */
 	@Override
 	public void undo() {
 		SharedCommandStackChangedEvent event = notifyListeners(SharedCommandStackListener.EVENT_START_UNDO);
 		if (!event.doit) return;

 		if (!canUndo()) return;
 		Context c = fContexts.get(fCurrentLocation-1);
 		c.fCommand.undo();
 		fCurrentLocation--;
 		// mark resources as dirty/clean as appropriate.
 		if (fCurrentLocation < saveLocation) {
 			// moving away from save location --> resources can only become dirty
 			c.setModifiedFlags(true);
 			// System.out.println("undo - markModified.  currentLocation="+currentLocation+", saveLocation="+saveLocation);
 		} else {
 			// moving towards save location --> resources can only become clean
 			updateModifiedFlags();
 		}

 		notifyListeners();
 		notifyListeners(SharedCommandStackListener.EVENT_FINISH_UNDO);
 	}


 	/**
 	 * @see org.eclipse.gef.commands.CommandStack#redo()
 	 */
 	@Override
 	public void redo() {
 		SharedCommandStackChangedEvent event = notifyListeners(SharedCommandStackListener.EVENT_START_REDO);
 		if (!event.doit) return;

 		if (!canRedo()) return;
 		Context c = fContexts.get(fCurrentLocation);
 		c.fCommand.redo();
 		fCurrentLocation++;
 		// mark resources as dirty/clean as appropriate.
 		if (fCurrentLocation > saveLocation) {
 			// moving away from save location --> resources can only become dirty
 			c.setModifiedFlags(true);
 			//System.out.println("redo - markModified.  currentLocation="+currentLocation+", saveLocation="+saveLocation);
 		} else {
 			// moving towards save location --> resources can only become clean
 			updateModifiedFlags();
 		}

 		if(getUndoCommand() instanceof PlaceHolderCommand) {
 			// This should never happen
 			throw new IllegalStateException();
 		}
 		notifyListeners();
 		notifyListeners(SharedCommandStackListener.EVENT_FINISH_REDO);
 	}

 	/**
 	 * Sends notification to all {@link CommandStackListener}s.
 	 */
 	protected SharedCommandStackChangedEvent notifyListeners(int property) {
 		SharedCommandStackChangedEvent event = new SharedCommandStackChangedEvent(this);
 		event.property = property;

 		for (Object next : listeners) {
 			CommandStackListener csl = (CommandStackListener) next;
 			csl.commandStackChanged(event);
 		}

 		return event;
 	}

 	/*
 	 * Helper to remove a command from any point in the stack.
 	 */
 	protected void drop (int pos) {
 		//System.out.println("  (drop "+pos+") C="+currentLocation+" S="+saveLocation);
 		if ((pos < 0) || pos >= fContexts.size()) {
 			throw new IllegalArgumentException();
 		}
 		Context c = fContexts.get(pos);
 		int a = Math.min(saveLocation, fCurrentLocation);
 		int b = Math.max(saveLocation, fCurrentLocation);
 		if ((a <= pos) && (pos < b)) {
 			// we're dropping something between current and save point.
 			dirtyUntilSave.addAll(Arrays.asList(c.fResources));
 			//System.out.println("dus = "+dirtyUntilSave);
 		}
 		c.fCommand.dispose();
 		fContexts.remove(pos);
 		if (fCurrentLocation > pos) {
 			fCurrentLocation--;
 		}
 		if (saveLocation > pos) {
 			saveLocation--;
 		}
 	}

 	/*
 	 * Helper to remove a range of commands from anywhere in the stack.
 	 */
 	protected void drop(int from, int to) {
 		if (to < from) { int a=to; to=from; from=a; }
 		//System.out.println("drop: "+to+".."+from);
 		while (to > from) { drop(from); to--; }
 	}

 	/*
 	 * Helper to mark a resource as clean or dirty (mostly for ease of debugging)
 	 */
 	protected static void setResourceModified(Resource r, boolean modified) {
 		if (r.isModified() != modified) {
 			//System.out.println("> "+modified+" : "+r);
 			r.setModified(modified);
 		}
 	}

 	/*
 	 * Helper to calculate which resources should be marked as dirty
 	 */
 	protected void updateModifiedFlags() {
 		//System.out.println("calculateModifiedState()");

 		Set<Resource> cleanResources = new HashSet<Resource>();
 		// for starters, treat everything as clean
 		for (Context c : fContexts) {
 			cleanResources.addAll(Arrays.asList(c.fResources));
 		}

 		// mark things that fell off the bottom of the undo stack as dirty
 		for (Resource resource : dirtyUntilSave) {
 			cleanResources.remove(resource);
 			setResourceModified(resource, true);
 		}
 		// mark things modified between saveLocation and currentLocation as dirty
 		int a = Math.min(fCurrentLocation, saveLocation);
 		int b = Math.max(fCurrentLocation, saveLocation);

 		for (int i = Math.max(a,0); i<b; i++) {
 			Context c = fContexts.get(i);
 			cleanResources.removeAll(Arrays.asList(c.fResources));
 			c.setModifiedFlags(true);
 		}
 		// mark anything we still consider clean as clean
 		for (Resource resource : cleanResources) {
 			setResourceModified(resource, false);
 		}
 	}


 	/**
 	 * SharedCommandStackListener
 	 *
 	 */
 	public static interface SharedCommandStackListener extends CommandStackListener {

 		public static final int EVENT_START_EXECUTE = 1;
 		public static final int EVENT_FINISH_EXECUTE = 2;
 		public static final int EVENT_START_UNDO = 3;
 		public static final int EVENT_FINISH_UNDO = 4;
 		public static final int EVENT_START_REDO = 5;
 		public static final int EVENT_FINISH_REDO = 6;
 		public static final int EVENT_START_FLUSH = 7;
 		public static final int EVENT_FINISH_FLUSH = 8;
 		public static final int EVENT_START_MARK_SAVED = 9;
 		public static final int EVENT_FINISH_MARK_SAVED = 10;

 		public static final int EVENT_DROP_LAST_UNDO_STACK_ENTRY = 11;
 		public static final int EVENT_MARK_SAVED = 12;

 	}

 	public static class SharedCommandStackChangedEvent extends EventObject {
 		int property;
 		public boolean doit = true;
 		SharedCommandStackChangedEvent(Object source) {	super(source); }
 		public EditModelCommandStack getStack() {
 			return (EditModelCommandStack)getSource();
 		}
 		public int getProperty() { return property; }
 	}

 	protected static Resource[] EMPTY_RESOURCE_ARRAY = new Resource[0];

 	// TODO: should this be in a utility class?  Can it be made extensible?
 	public static Resource[] getResources(Command command) {
 		if (command instanceof IEditModelCommand) {
 			return ((IEditModelCommand)command).getResources();
 		}
 		if (command instanceof CompoundCommand) {
 			CompoundCommand ccmd = (CompoundCommand) command;

 			Set<Resource> set = new HashSet<Resource>();
 			for (Object n : ccmd.getChildren() ) {
 				for (Resource r : getResources((Command)n)) {
 					set.add(r);
 				}
 			}
 			if (set.isEmpty()) {
 				return EMPTY_RESOURCE_ARRAY;
 			}
 			return set.toArray( EMPTY_RESOURCE_ARRAY );		}

 		throw new IllegalArgumentException();
 	}

 	// TODO: should this be in a utility class?  Can it be made extensible?
 	public static Resource[] getModifiedResources(Command command) {

 		if (command instanceof IEditModelCommand) {
 			return ((IEditModelCommand)command).getModifiedResources();
 		}
 		if (command instanceof CompoundCommand) {
 			CompoundCommand ccmd = (CompoundCommand) command;

 			Set<Resource> set = new HashSet<Resource>();
 			for (Object n : ccmd.getChildren() ) {
 				for (Resource r : getModifiedResources((Command)n)) {
 					set.add(r);
 				}
 			}
 			if (set.isEmpty()) {
 				return EMPTY_RESOURCE_ARRAY;
 			}
 			return set.toArray( EMPTY_RESOURCE_ARRAY );
 		}

 		throw new IllegalArgumentException();
 	}


 	protected static class Context {

 		public Command fCommand;
 		public Resource[] fResources;

 		public Context(Command command, Resource[] resources) {
 			this.fCommand = command;
 			this.fResources = resources;
 		}
 		public void setModifiedFlags (boolean value) {
 			for (Resource r : fResources) {
 				setResourceModified(r, value);
 			}
 		}

 	}

 }
	/*******************************************************************************
	* Copyright (c) 2005 IBM Corporation and others.
	* 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:
	* IBM Corporation - initial API and implementation
	*******************************************************************************/
	package org.eclipse.bpel.common.ui.editmodel;

	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.EventObject;
	import java.util.HashSet;
	import java.util.List;
	import java.util.Set;

	import org.eclipse.bpel.common.ui.CommonUIPlugin;
	import org.eclipse.bpel.common.ui.Messages;
	import org.eclipse.core.resources.IFile;
	import org.eclipse.core.resources.ResourcesPlugin;
	import org.eclipse.core.runtime.IStatus;
	import org.eclipse.emf.ecore.resource.Resource;
	import org.eclipse.gef.commands.Command;
	import org.eclipse.gef.commands.CommandStack;
	import org.eclipse.gef.commands.CommandStackListener;
	import org.eclipse.gef.commands.CompoundCommand;
	import org.eclipse.jface.dialogs.IDialogConstants;
	import org.eclipse.jface.dialogs.MessageDialog;
	import org.eclipse.osgi.util.NLS;
	import org.eclipse.swt.widgets.Shell;
	import org.eclipse.ui.IWorkbenchWindow;



	/**
	* Implements the CommandStack API, adds extra notifications,
	* supports validateEdit and update the resource's dirty state.
	*
	* WDG: TODO: the GEF CommandStack has been extended with extra notifications.
	* However, how are we supposed to use it since everything is still private?
	*/
	public class EditModelCommandStack extends CommandStack {

	protected int saveLocation = 0;
	protected int fCurrentLocation = 0;

	protected Set<Resource> dirtyUntilSave = new HashSet<Resource>();

	protected List<Context> fContexts = new ArrayList<Context>(30);

	/**
	* Brand new shiny EditModelCommandStack.
	*/
	public EditModelCommandStack() {
	super();
	}

	/**
	* @see org.eclipse.gef.commands.CommandStack#getUndoCommand()
	*/
	@Override
	public Command getUndoCommand() {
	if (fCurrentLocation < 1) {
	return null;
	}
	return fContexts.get(fCurrentLocation-1).fCommand;
	}

	/**
	* @see org.eclipse.gef.commands.CommandStack#canUndo()
	*/
	@Override
	public boolean canUndo() {
	Command c = getUndoCommand();
	return (c != null) && c.canUndo();
	}


	/**
	* @see org.eclipse.gef.commands.CommandStack#getRedoCommand()
	*/
	@Override
	public Command getRedoCommand() {
	if (fCurrentLocation >= fContexts.size()) return null;
	return fContexts.get(fCurrentLocation).fCommand;
	}

	/**
	* @see org.eclipse.gef.commands.CommandStack#canRedo()
	*/
	@Override
	public boolean canRedo() {
	return (getRedoCommand() != null);
	}

	/**
	* @see org.eclipse.gef.commands.CommandStack#execute(org.eclipse.gef.commands.Command)
	*/
	@Override
	public void execute (Command command) {
	SharedCommandStackChangedEvent event = notifyListeners(SharedCommandStackListener.EVENT_START_EXECUTE);
	if (!event.doit) return;

	if(getUndoCommand() instanceof PlaceHolderCommand) {
	// This should never happen because the EditModelCommandFramework should
	// remove the placeholder during the notifyListeners() call above.
	throw new IllegalStateException();
	}
	if (command == null) return;
	if (!validateEdit(command)) return;
	if (!command.canExecute()) return;
	drop(fCurrentLocation, fContexts.size());

	// Paranoia check
	if(getUndoCommand() instanceof PlaceHolderCommand) {
	// This should never happen because the EditModelCommandFramework should
	// remove the placeholder during the notifyListeners() call above.
	throw new IllegalStateException();
	}
	command.execute();
	if(getUndoCommand() instanceof PlaceHolderCommand) {
	// This should never happen because the EditModelCommandFramework should
	// remove the placeholder during the notifyListeners() call above.
	throw new IllegalStateException();
	}
	int limit = getUndoLimit();
	if (limit > 0) while (fCurrentLocation >= limit) {
	if (saveLocation == 0) saveLocation = -1;
	drop(0);
	notifyListeners(SharedCommandStackListener.EVENT_DROP_LAST_UNDO_STACK_ENTRY);
	}
	if(getUndoCommand() instanceof PlaceHolderCommand) {
	// This should never happen because the EditModelCommandFramework should
	// remove the placeholder during the notifyListeners() call above.
	throw new IllegalStateException();
	}
	Resource[] resources = getModifiedResources(command);
	if ((resources.length > 0) \|\| (command instanceof PlaceHolderCommand)) {
	Context c = new Context(command, resources);
	fContexts.add(c); fCurrentLocation = fContexts.size();
	// mark resources as dirty/clean as appropriate.
	c.setModifiedFlags(true);
	//System.out.println("execute - markModified. currentLocation="+currentLocation+", saveLocation="+saveLocation);
	}
	notifyListeners(SharedCommandStackListener.EVENT_FINISH_EXECUTE);
	}
	/*
	* call VCM validateEdit;
	* open the dialog to ask the user if he/she wants to procede
	* in case the file is readonly;
	* return true if the command should be executed otherwise returns false;
	*/
	protected boolean validateEdit(Command command) {
	Resource[] resources = getResources(command);
	if(resources.length == 0)
	return true;
	boolean disposeShell = false;
	Shell shell;
	IWorkbenchWindow win = CommonUIPlugin.getDefault().getWorkbench().getActiveWorkbenchWindow();
	if (win != null) {
	shell = win.getShell();
	} else {
	disposeShell = true;
	shell = new Shell();
	}
	try {
	IFile[] files = new IFile[resources.length];
	StringBuffer filesString = new StringBuffer();
	for (int i = 0; i < resources.length; i++) {
	Resource resource = resources[i];
	files[i] = EditModel.getIFileForURI(resource.getURI());
	filesString.append(files[i].getName());
	if(i < resources.length - 1)
	filesString.append(", "); //$NON-NLS-1$
	}
	IStatus stat = ResourcesPlugin.getWorkspace().validateEdit(files, shell);
	if (stat.getSeverity() == IStatus.CANCEL) {
	return false;
	} else if (!stat.isOK()) {
	String[] buttons = { IDialogConstants.OK_LABEL }; //
	String msg;
	if(files.length == 1)
	msg = NLS.bind(Messages.EditModelCommandStack_validateEdit_message0, (new String[]{filesString.toString(),stat.getMessage()}));
	else
	msg = NLS.bind(Messages.EditModelCommandStack_validateEdit_message1, (new String[]{filesString.toString(),stat.getMessage()}));
	MessageDialog dialog = new MessageDialog(
	shell,
	Messages.EditModelCommandStack_validateEdit_title,
	null, // accept the default windowing system icon
	msg,
	MessageDialog.WARNING,
	buttons,
	0);
	dialog.open();
	return false;
	}
	} finally {
	if(disposeShell)
	shell.dispose();
	}
	return true;
	}

	/**
	* @see org.eclipse.gef.commands.CommandStack#dispose()
	*/
	@Override
	public void dispose() {
	drop(0,fContexts.size());
	}

	/**
	* @see org.eclipse.gef.commands.CommandStack#flush()
	*/
	@Override
	public void flush() {
	SharedCommandStackChangedEvent event = notifyListeners(SharedCommandStackListener.EVENT_START_FLUSH);
	if (!event.doit) return;

	drop(0, fContexts.size());
	fContexts.clear();
	saveLocation = -1;
	fCurrentLocation = 0;
	// TODO: should we mark all resources as clean?
	notifyListeners(SharedCommandStackListener.EVENT_FINISH_FLUSH);
	}

	/**
	* @see org.eclipse.gef.commands.CommandStack#getCommands()
	*/
	@Override
	public Object[] getCommands() {
	Object[] commands = new Object[fContexts.size()];
	for (int i = 0; i < fContexts.size(); i++) {
	commands[i] = fContexts.get(i).fCommand;
	}
	return commands;
	}


	/**
	* @see org.eclipse.gef.commands.CommandStack#isDirty()
	*/
	@Override
	public boolean isDirty() {
	//System.out.println("isDirty: C="+currentLocation+" S="+saveLocation+" dus="+dirtyUntilSave.size());
	return (fCurrentLocation != saveLocation) \|\| !dirtyUntilSave.isEmpty();
	}

	/**
	* @see org.eclipse.gef.commands.CommandStack#markSaveLocation()
	*/
	@Override
	public void markSaveLocation() {
	// // mark all the resources we know about as clean!
	// for (int i = 0; i<contexts.size(); i++) {
	// Context c = (Context)contexts.get(i);
	// c.setModifiedFlags(false);
	// }
	// // that includes ones that fell off the bottom of the undo stack.
	// for (Iterator it = dirtyUntilSave.iterator(); it.hasNext(); ) {
	// setResourceModified((Resource)it.next(), false);
	// }
	dirtyUntilSave.clear();

	saveLocation = fCurrentLocation;
	notifyListeners(SharedCommandStackListener.EVENT_MARK_SAVED);
	}

	/**
	* @see org.eclipse.gef.commands.CommandStack#undo()
	*/
	@Override
	public void undo() {
	SharedCommandStackChangedEvent event = notifyListeners(SharedCommandStackListener.EVENT_START_UNDO);
	if (!event.doit) return;

	if (!canUndo()) return;
	Context c = fContexts.get(fCurrentLocation-1);
	c.fCommand.undo();
	fCurrentLocation--;
	// mark resources as dirty/clean as appropriate.
	if (fCurrentLocation < saveLocation) {
	// moving away from save location --> resources can only become dirty
	c.setModifiedFlags(true);
	// System.out.println("undo - markModified. currentLocation="+currentLocation+", saveLocation="+saveLocation);
	} else {
	// moving towards save location --> resources can only become clean
	updateModifiedFlags();
	}

	notifyListeners();
	notifyListeners(SharedCommandStackListener.EVENT_FINISH_UNDO);
	}


	/**
	* @see org.eclipse.gef.commands.CommandStack#redo()
	*/
	@Override
	public void redo() {
	SharedCommandStackChangedEvent event = notifyListeners(SharedCommandStackListener.EVENT_START_REDO);
	if (!event.doit) return;

	if (!canRedo()) return;
	Context c = fContexts.get(fCurrentLocation);
	c.fCommand.redo();
	fCurrentLocation++;
	// mark resources as dirty/clean as appropriate.
	if (fCurrentLocation > saveLocation) {
	// moving away from save location --> resources can only become dirty
	c.setModifiedFlags(true);
	//System.out.println("redo - markModified. currentLocation="+currentLocation+", saveLocation="+saveLocation);
	} else {
	// moving towards save location --> resources can only become clean
	updateModifiedFlags();
	}

	if(getUndoCommand() instanceof PlaceHolderCommand) {
	// This should never happen
	throw new IllegalStateException();
	}
	notifyListeners();
	notifyListeners(SharedCommandStackListener.EVENT_FINISH_REDO);
	}

	/**
	* Sends notification to all {@link CommandStackListener}s.
	*/
	protected SharedCommandStackChangedEvent notifyListeners(int property) {
	SharedCommandStackChangedEvent event = new SharedCommandStackChangedEvent(this);
	event.property = property;

	for (Object next : listeners) {
	CommandStackListener csl = (CommandStackListener) next;
	csl.commandStackChanged(event);
	}

	return event;
	}

	/*
	* Helper to remove a command from any point in the stack.
	*/
	protected void drop (int pos) {
	//System.out.println(" (drop "+pos+") C="+currentLocation+" S="+saveLocation);
	if ((pos < 0) \|\| pos >= fContexts.size()) {
	throw new IllegalArgumentException();
	}
	Context c = fContexts.get(pos);
	int a = Math.min(saveLocation, fCurrentLocation);
	int b = Math.max(saveLocation, fCurrentLocation);
	if ((a <= pos) && (pos < b)) {
	// we're dropping something between current and save point.
	dirtyUntilSave.addAll(Arrays.asList(c.fResources));
	//System.out.println("dus = "+dirtyUntilSave);
	}
	c.fCommand.dispose();
	fContexts.remove(pos);
	if (fCurrentLocation > pos) {
	fCurrentLocation--;
	}
	if (saveLocation > pos) {
	saveLocation--;
	}
	}

	/*
	* Helper to remove a range of commands from anywhere in the stack.
	*/
	protected void drop(int from, int to) {
	if (to < from) { int a=to; to=from; from=a; }
	//System.out.println("drop: "+to+".."+from);
	while (to > from) { drop(from); to--; }
	}

	/*
	* Helper to mark a resource as clean or dirty (mostly for ease of debugging)
	*/
	protected static void setResourceModified(Resource r, boolean modified) {
	if (r.isModified() != modified) {
	//System.out.println("> "+modified+" : "+r);
	r.setModified(modified);
	}
	}

	/*
	* Helper to calculate which resources should be marked as dirty
	*/
	protected void updateModifiedFlags() {
	//System.out.println("calculateModifiedState()");

	Set<Resource> cleanResources = new HashSet<Resource>();
	// for starters, treat everything as clean
	for (Context c : fContexts) {
	cleanResources.addAll(Arrays.asList(c.fResources));
	}

	// mark things that fell off the bottom of the undo stack as dirty
	for (Resource resource : dirtyUntilSave) {
	cleanResources.remove(resource);
	setResourceModified(resource, true);
	}
	// mark things modified between saveLocation and currentLocation as dirty
	int a = Math.min(fCurrentLocation, saveLocation);
	int b = Math.max(fCurrentLocation, saveLocation);

	for (int i = Math.max(a,0); i<b; i++) {
	Context c = fContexts.get(i);
	cleanResources.removeAll(Arrays.asList(c.fResources));
	c.setModifiedFlags(true);
	}
	// mark anything we still consider clean as clean
	for (Resource resource : cleanResources) {
	setResourceModified(resource, false);
	}
	}


	/**
	* SharedCommandStackListener
	*
	*/
	public static interface SharedCommandStackListener extends CommandStackListener {

	public static final int EVENT_START_EXECUTE = 1;
	public static final int EVENT_FINISH_EXECUTE = 2;
	public static final int EVENT_START_UNDO = 3;
	public static final int EVENT_FINISH_UNDO = 4;
	public static final int EVENT_START_REDO = 5;
	public static final int EVENT_FINISH_REDO = 6;
	public static final int EVENT_START_FLUSH = 7;
	public static final int EVENT_FINISH_FLUSH = 8;
	public static final int EVENT_START_MARK_SAVED = 9;
	public static final int EVENT_FINISH_MARK_SAVED = 10;

	public static final int EVENT_DROP_LAST_UNDO_STACK_ENTRY = 11;
	public static final int EVENT_MARK_SAVED = 12;

	}

	public static class SharedCommandStackChangedEvent extends EventObject {
	int property;
	public boolean doit = true;
	SharedCommandStackChangedEvent(Object source) { super(source); }
	public EditModelCommandStack getStack() {
	return (EditModelCommandStack)getSource();
	}
	public int getProperty() { return property; }
	}

	protected static Resource[] EMPTY_RESOURCE_ARRAY = new Resource[0];

	// TODO: should this be in a utility class? Can it be made extensible?
	public static Resource[] getResources(Command command) {
	if (command instanceof IEditModelCommand) {
	return ((IEditModelCommand)command).getResources();
	}
	if (command instanceof CompoundCommand) {
	CompoundCommand ccmd = (CompoundCommand) command;

	Set<Resource> set = new HashSet<Resource>();
	for (Object n : ccmd.getChildren() ) {
	for (Resource r : getResources((Command)n)) {
	set.add(r);
	}
	}
	if (set.isEmpty()) {
	return EMPTY_RESOURCE_ARRAY;
	}
	return set.toArray( EMPTY_RESOURCE_ARRAY ); }

	throw new IllegalArgumentException();
	}

	// TODO: should this be in a utility class? Can it be made extensible?
	public static Resource[] getModifiedResources(Command command) {

	if (command instanceof IEditModelCommand) {
	return ((IEditModelCommand)command).getModifiedResources();
	}
	if (command instanceof CompoundCommand) {
	CompoundCommand ccmd = (CompoundCommand) command;

	Set<Resource> set = new HashSet<Resource>();
	for (Object n : ccmd.getChildren() ) {
	for (Resource r : getModifiedResources((Command)n)) {
	set.add(r);
	}
	}
	if (set.isEmpty()) {
	return EMPTY_RESOURCE_ARRAY;
	}
	return set.toArray( EMPTY_RESOURCE_ARRAY );
	}

	throw new IllegalArgumentException();
	}


	protected static class Context {

	public Command fCommand;
	public Resource[] fResources;

	public Context(Command command, Resource[] resources) {
	this.fCommand = command;
	this.fResources = resources;
	}
	public void setModifiedFlags (boolean value) {
	for (Resource r : fResources) {
	setResourceModified(r, value);
	}
	}

	}

	}