core/plugins/org.eclipse.mdht.uml.ui.navigator/src/org/eclipse/mdht/uml/ui/navigator/internal/plugin/Activator.java

/*******************************************************************************
 * Copyright (c) 2006, 2009 David A Carlson.
 * 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:
 *     David A Carlson (XMLmodeling.com) - initial API and implementation
 *
 * $Id$
 *******************************************************************************/
package org.eclipse.mdht.uml.ui.navigator.internal.plugin;

import org.eclipse.core.runtime.IPath;
import org.eclipse.core.runtime.Path;
import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.swt.graphics.Image;
import org.eclipse.ui.plugin.AbstractUIPlugin;
import org.osgi.framework.BundleContext;

/**
 * The activator class controls the plug-in life cycle
 */
public class Activator extends AbstractUIPlugin {

	// The plug-in ID
	public static final String PLUGIN_ID = "org.eclipse.mdht.uml.ui.navigator";

	// The shared instance
	private static Activator plugin;

	/**
	 * The constructor
	 */
	public Activator() {
		plugin = this;
	}

	/*
	 * (non-Javadoc)
	 *
	 * @see org.eclipse.ui.plugin.AbstractUIPlugin#start(org.osgi.framework.BundleContext)
	 */
	@Override
	public void start(BundleContext context) throws Exception {
		super.start(context);
	}

	/*
	 * (non-Javadoc)
	 *
	 * @see org.eclipse.ui.plugin.AbstractUIPlugin#stop(org.osgi.framework.BundleContext)
	 */
	@Override
	public void stop(BundleContext context) throws Exception {
		plugin = null;
		super.stop(context);
	}

	/**
	 * Returns the shared instance
	 *
	 * @return the shared instance
	 */
	public static Activator getDefault() {
		return plugin;
	}

	/**
	 * Returns an image descriptor for the image file at the given
	 * plug-in relative path.
	 *
	 * @param path
	 *            the path
	 * @return the image descriptor
	 */
	public static ImageDescriptor getBundledImageDescriptor(String path) {
		return AbstractUIPlugin.imageDescriptorFromPlugin(PLUGIN_ID, path);
	}

	/**
	 * Respects images residing in any plug-in. If path is relative,
	 * then this bundle is looked up for the image, otherwise, for absolute
	 * path, first segment is taken as id of plug-in with image
	 *
	 * @param path
	 *            the path to image, either absolute (with plug-in id as first segment), or relative for bundled images
	 * @return the image descriptor
	 */
	public static ImageDescriptor findImageDescriptor(String path) {
		final IPath p = new Path(path);
		if (p.isAbsolute() && p.segmentCount() > 1) {
			return AbstractUIPlugin.imageDescriptorFromPlugin(
				p.segment(0), p.removeFirstSegments(1).makeAbsolute().toString());
		} else {
			return getBundledImageDescriptor(p.makeAbsolute().toString());
		}
	}

	/**
	 * Returns an image for the image file at the given plug-in relative path.
	 * Client do not need to dispose this image. Images will be disposed automatically.
	 *
	 * @param path
	 *            the path
	 * @return image instance
	 */
	public Image getBundledImage(String path) {
		Image image = getImageRegistry().get(path);
		if (image == null) {
			getImageRegistry().put(path, getBundledImageDescriptor(path));
			image = getImageRegistry().get(path);
		}
		return image;
	}

}