bundles/org.eclipse.e4.tools.emf.ui/src/org/eclipse/e4/tools/emf/ui/internal/ObservableColumnLabelProvider.java

/*******************************************************************************
 * Copyright (c) 2010 BestSolution.at 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:
 *     Tom Schindl <tom.schindl@bestsolution.at> - initial API and implementation
 ******************************************************************************/
package org.eclipse.e4.tools.emf.ui.internal;

import java.util.Set;
import org.eclipse.core.databinding.observable.map.IMapChangeListener;
import org.eclipse.core.databinding.observable.map.IObservableMap;
import org.eclipse.core.databinding.observable.map.MapChangeEvent;
import org.eclipse.jface.viewers.CellLabelProvider;
import org.eclipse.jface.viewers.LabelProviderChangedEvent;
import org.eclipse.jface.viewers.ViewerCell;
import org.eclipse.swt.graphics.Color;
import org.eclipse.swt.graphics.Font;
import org.eclipse.swt.graphics.Image;

public class ObservableColumnLabelProvider<M> extends CellLabelProvider {
	private IObservableMap[] attributeMaps;

	private IMapChangeListener mapChangeListener = new IMapChangeListener() {
		public void handleMapChange(MapChangeEvent event) {
			Set<?> affectedElements = event.diff.getChangedKeys();
			LabelProviderChangedEvent newEvent = new LabelProviderChangedEvent(
					ObservableColumnLabelProvider.this, affectedElements
							.toArray());
			fireLabelProviderChanged(newEvent);
		}
	};

	/**
	 * Creates a new label provider that tracks changes to one attribute.
	 * 
	 * @param attributeMap
	 */
	public ObservableColumnLabelProvider(IObservableMap attributeMap) {
		this(new IObservableMap[] { attributeMap });
	}

	/**
	 * Creates a new label provider that tracks changes to more than one
	 * attribute. This constructor should be used by subclasses that override
	 * {@link #update(ViewerCell)} and make use of more than one attribute.
	 * 
	 * @param attributeMaps
	 */
	protected ObservableColumnLabelProvider(IObservableMap[] attributeMaps) {
		System.arraycopy(attributeMaps, 0,
				this.attributeMaps = new IObservableMap[attributeMaps.length],
				0, attributeMaps.length);
		for (int i = 0; i < attributeMaps.length; i++) {
			attributeMaps[i].addMapChangeListener(mapChangeListener);
		}
	}

	public void dispose() {
		for (int i = 0; i < attributeMaps.length; i++) {
			attributeMaps[i].removeMapChangeListener(mapChangeListener);
		}
		super.dispose();
		this.attributeMaps = null;
		this.mapChangeListener = null;
	}

	@SuppressWarnings("unchecked")
	public void update(ViewerCell cell) {
		M element = (M) cell.getElement();
		cell.setText(getText(element));
		cell.setImage(getImage(element));
		cell.setBackground(getBackground(element));
		cell.setForeground(getForeground(element));
		cell.setFont(getFont(element));
	}

	public String getText(M element) {
		Object value = attributeMaps[0].get(element);
		return value == null ? "" : value.toString(); //$NON-NLS-1$
	}
	
	public Font getFont(M element) {
		return null;
	}

	public Color getBackground(M element) {
		return null;
	}

	public Color getForeground(M element) {
		return null;
	}


	public Image getImage(M element) {
		return null;
	}

}