Activator.java

/*******************************************************************************
 * Copyright (c) 2008 Olivier Moises
 *
 * 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:
 *   Olivier Moises- initial API and implementation
 *******************************************************************************/

package org.eclipse.wazaabi.locator.platform.plugin;

import org.osgi.framework.Bundle;
import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
import org.osgi.service.packageadmin.PackageAdmin;
import org.osgi.util.tracker.ServiceTracker;

public class Activator implements BundleActivator {

	// The shared instance
	private static Activator activator;
	
	private static BundleContext context;
	private ServiceTracker pkgAdminTracker;

	public static Activator getDefault() {
		return activator;
	}

	static BundleContext getContext() {
		return context;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.osgi.framework.BundleActivator#start(org.osgi.framework.BundleContext
	 * )
	 */
	public void start(BundleContext bundleContext) throws Exception {
		Activator.context = bundleContext;
		activator = this;
	}

	/*
	 * (non-Javadoc)
	 * 
	 * @see
	 * org.osgi.framework.BundleActivator#stop(org.osgi.framework.BundleContext)
	 */
	public void stop(BundleContext bundleContext) throws Exception {
		Activator.context = null;
		activator = null;
		if (pkgAdminTracker != null) {
			pkgAdminTracker.close();
			pkgAdminTracker = null;
		}
	}

	/**
	 * @return the PackageAdmin service from this bundle
	 */
	public PackageAdmin getBundleAdmin() {
		if (pkgAdminTracker == null) {
			if (context == null)
				return null;
			pkgAdminTracker = new ServiceTracker(context,
					PackageAdmin.class.getName(), null);
			pkgAdminTracker.open();
		}
		return (PackageAdmin) pkgAdminTracker.getService();
	}

	/**
	 * @param bundleName
	 *            the bundle id
	 * @return A bundle if found, or <code>null</code>
	 */
	public Bundle getBundleForName(String bundleName) {
		Bundle[] bundles = getBundleAdmin().getBundles(bundleName, null);
		if (bundles == null)
			return null;
		// Return the first bundle that is not installed or uninstalled
		for (int i = 0; i < bundles.length; i++) {
			if ((bundles[i].getState() & (Bundle.INSTALLED | Bundle.UNINSTALLED)) == 0) {
				return bundles[i];
			}
		}
		return null;
	}
}