MultiRosterLabelProvider.java

/****************************************************************************
 * Copyright (c) 2004, 2007 Composent, Inc. 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:
 *    Composent, Inc. - initial API and implementation
 *****************************************************************************/
package org.eclipse.ecf.presence.ui;

import java.util.HashMap;
import java.util.Iterator;
import java.util.Map;

import org.eclipse.core.runtime.IAdaptable;
import org.eclipse.core.runtime.Platform;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.jface.viewers.LabelProvider;
import org.eclipse.swt.graphics.Image;
import org.eclipse.ui.model.IWorkbenchAdapter;

/**
 * Label provider for multiple roster viewer. This label provider implements an
 * LabelProvider suitable for use by viewers that accepts LabelProvider as
 * input. This class may be subclassed in order to customize the
 * behavior/display of other label providers.
 * 
 */
public class MultiRosterLabelProvider extends LabelProvider {

	private Map imageTable = new HashMap(7);

	/**
	 * @param element
	 * @return IWorkbenchAdapter for the given element
	 */
	protected IWorkbenchAdapter getAdapter(Object element) {
		IWorkbenchAdapter adapter = null;
		if (element instanceof IAdaptable)
			adapter = (IWorkbenchAdapter) ((IAdaptable) element)
					.getAdapter(IWorkbenchAdapter.class);
		if (element != null && adapter == null)
			adapter = (IWorkbenchAdapter) Platform.getAdapterManager()
					.loadAdapter(element, IWorkbenchAdapter.class.getName());
		return adapter;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.viewers.LabelProvider#getImage(java.lang.Object)
	 */
	public Image getImage(Object element) {
		IWorkbenchAdapter adapter = getAdapter(element);
		if (adapter == null)
			return null;
		ImageDescriptor descriptor = adapter.getImageDescriptor(element);
		if (descriptor == null)
			return null;
		Image image = (Image) imageTable.get(descriptor);
		if (image == null) {
			image = descriptor.createImage();
			imageTable.put(descriptor, image);
		}
		return image;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.viewers.LabelProvider#getText(java.lang.Object)
	 */
	public String getText(Object element) {
		IWorkbenchAdapter adapter = getAdapter(element);
		return adapter == null ? "" : adapter.getLabel(element); //$NON-NLS-1$
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see org.eclipse.jface.viewers.BaseLabelProvider#dispose()
	 */
	public void dispose() {
		if (imageTable != null) {
			for (Iterator i = imageTable.values().iterator(); i.hasNext();) {
				((Image) i.next()).dispose();
			}
			imageTable = null;
		}
	}

}