/* 
 * Copyright (c) 2006 Stiftung Deutsches Elektronen-Synchroton, 
 * Member of the Helmholtz Association, (DESY), HAMBURG, GERMANY.
 *
 * THIS SOFTWARE IS PROVIDED UNDER THIS LICENSE ON AN "../AS IS" BASIS. 
 * WITHOUT WARRANTY OF ANY KIND, EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED 
 * TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR PARTICULAR PURPOSE AND 
 * NON-INFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE 
 * FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR 
 * THE USE OR OTHER DEALINGS IN THE SOFTWARE. SHOULD THE SOFTWARE PROVE DEFECTIVE 
 * IN ANY RESPECT, THE USER ASSUMES THE COST OF ANY NECESSARY SERVICING, REPAIR OR 
 * CORRECTION. THIS DISCLAIMER OF WARRANTY CONSTITUTES AN ESSENTIAL PART OF THIS LICENSE. 
 * NO USE OF ANY SOFTWARE IS AUTHORIZED HEREUNDER EXCEPT UNDER THIS DISCLAIMER.
 * DESY HAS NO OBLIGATION TO PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, 
 * OR MODIFICATIONS.
 * THE FULL LICENSE SPECIFYING FOR THE SOFTWARE THE REDISTRIBUTION, MODIFICATION, 
 * USAGE AND OTHER RIGHTS AND OBLIGATIONS IS INCLUDED WITH THE DISTRIBUTION OF THIS 
 * PROJECT IN THE FILE LICENSE.HTML. IF THE LICENSE IS NOT INCLUDED YOU MAY FIND A COPY 
 * AT HTTP://WWW.DESY.DE/LEGAL/LICENSE.HTM
 */
package org.csstudio.sds.ui.internal.editparts;

import java.util.ArrayList;
import java.util.List;

import org.csstudio.sds.model.PropertyChangeAdapter;
import org.csstudio.sds.ui.CheckedUiRunnable;
import org.csstudio.sds.ui.editparts.AbstractBaseEditPart;
import org.csstudio.sds.ui.editparts.IWidgetPropertyChangeHandler;
import org.eclipse.draw2d.IFigure;

/**
 * A <code>IPropertyChangeListener</code> implementation, which delegates
 * property change events to a handler, which is registered separately.
 * 
 * This is used to implement a fine grained property handling in the UI.
 * 
 * @author Sven Wende
 * 
 */
public final class WidgetPropertyChangeListener extends PropertyChangeAdapter {

	/**
	 * Backlink to an EditPart.
	 */
	private AbstractBaseEditPart _editPart;

	/**
	 * The handlers, which really does the action in case of a property change
	 * event. Is empty by default.
	 */
	private List<IWidgetPropertyChangeHandler> _handlers;

	/**
	 * Constructs a listener.
	 * 
	 * @param editPart
	 *            backlink to the EditPart, which uses this listener
	 */
	public WidgetPropertyChangeListener(final AbstractBaseEditPart editPart) {
		assert editPart != null;
		_editPart = editPart;
		_handlers = new ArrayList<IWidgetPropertyChangeHandler>();
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public void propertyValueChanged(final Object oldValue,
			final Object newValue) {
		new CheckedUiRunnable() {
			@Override
			protected void doRunInUi() {
				for (IWidgetPropertyChangeHandler h : _handlers) {
					IFigure figure = _editPart.getFigure();

					boolean repaint = h
							.handleChange(oldValue, newValue, figure);
					
					if (repaint) {
						figure.repaint();
					}
				}
			}
		};
	}

	/**
	 * Sets a handler, which is informed, when a property change occurs.
	 * 
	 * @param handler
	 *            the handler
	 */
	public void addHandler(final IWidgetPropertyChangeHandler handler) {
		assert handler != null;
		_handlers.add(handler);
	}
}