UndoablePropertySheetEntry.java

/*******************************************************************************
 * Copyright (c) 2000, 2008 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.gef.ui.properties;

import java.util.EventObject;

import org.eclipse.ui.views.properties.IPropertySource;
import org.eclipse.ui.views.properties.PropertySheetEntry;

import org.eclipse.gef.commands.CommandStack;
import org.eclipse.gef.commands.CommandStackListener;
import org.eclipse.gef.commands.CompoundCommand;
import org.eclipse.gef.commands.ForwardUndoCompoundCommand;

/**
 * <p>
 * UndoablePropertySheetEntry provides undo support for changes made to IPropertySources
 * by the PropertySheetViewer. Clients can
 * construct a {@link org.eclipse.ui.views.properties.PropertySheetPage} and use this
 * class as the root entry. All changes made to property sources displayed on that page
 * will be done using the provided command stack.
 * <p>
 * <b>NOTE:</b> If you intend to use an IPropertySourceProvider for a PropertySheetPage
 * whose root entry is an instance of of UndoablePropertySheetEntry, you should set the 
 * IPropertySourceProvider on that root entry, rather than the PropertySheetPage.
 */
public final class UndoablePropertySheetEntry extends PropertySheetEntry {

private CommandStackListener commandStackListener;

private CommandStack stack;

private UndoablePropertySheetEntry() { }

/**
 * Constructs the root entry using the given command stack.
 * @param stack the command stack
 * @since 3.1
 */
public UndoablePropertySheetEntry(CommandStack stack) {
	setCommandStack(stack);
}

/**
 * @see org.eclipse.ui.views.properties.PropertySheetEntry#createChildEntry()
 */
protected PropertySheetEntry createChildEntry() {
	return new UndoablePropertySheetEntry();
}

/**
 * @see org.eclipse.ui.views.properties.IPropertySheetEntry#dispose()
 */
public void dispose() {
	if (stack != null)
		stack.removeCommandStackListener(commandStackListener);
	super.dispose();
}

CommandStack getCommandStack() {
	//only the root has, and is listening too, the command stack
	if (getParent() != null)
		return ((UndoablePropertySheetEntry)getParent()).getCommandStack();
	return stack;
}

/**
 * @see org.eclipse.ui.views.properties.IPropertySheetEntry#resetPropertyValue()
 */
public void resetPropertyValue() {
	CompoundCommand cc = new CompoundCommand();
	ResetValueCommand restoreCmd;

	if (getParent() == null)
		// root does not have a default value
		return;

	//	Use our parent's values to reset our values.
	boolean change = false;
	Object[] objects = getParent().getValues();
	for (int i = 0; i < objects.length; i++) {
		IPropertySource source = getPropertySource(objects[i]);
		if (source.isPropertySet(getDescriptor().getId())) {
			//source.resetPropertyValue(getDescriptor()getId());
			restoreCmd = new ResetValueCommand();
			restoreCmd.setTarget(source);
			restoreCmd.setPropertyId(getDescriptor().getId());
			cc.add(restoreCmd);			
			change = true;
		}
	}
	if (change) {
		getCommandStack().execute(cc);
		refreshFromRoot();
	}
}

void setCommandStack(CommandStack stack) {
	this.stack = stack;
	commandStackListener = new CommandStackListener() {
		public void commandStackChanged(EventObject e) {
			refreshFromRoot();
		}
	};
	stack.addCommandStackListener(commandStackListener);
}

/**
 * @see PropertySheetEntry#valueChanged(PropertySheetEntry)
 */
protected void valueChanged(PropertySheetEntry child) {
	valueChanged((UndoablePropertySheetEntry)child,
			new ForwardUndoCompoundCommand());
}

void valueChanged(UndoablePropertySheetEntry child, CompoundCommand command) {
	CompoundCommand cc = new CompoundCommand();
	command.add(cc);

	SetValueCommand setCommand;
	for (int i = 0; i < getValues().length; i++) {
		setCommand = new SetValueCommand(child.getDisplayName());
		setCommand.setTarget(getPropertySource(getValues()[i]));
		setCommand.setPropertyId(child.getDescriptor().getId());
		setCommand.setPropertyValue(child.getValues()[i]);
		cc.add(setCommand);
	}

	// inform our parent
	if (getParent() != null)
		((UndoablePropertySheetEntry)getParent()).valueChanged(this, command);
	else {
		//I am the root entry
		stack.execute(command);
	}
}
}