examples/org.eclipse.equinox.p2.examples.rcp.prestartupdate/src/org/eclipse/equinox/p2/examples/rcp/prestartupdate/Activator.java

package org.eclipse.equinox.p2.examples.rcp.prestartupdate;

import org.eclipse.jface.resource.ImageDescriptor;
import org.eclipse.ui.plugin.AbstractUIPlugin;
import org.osgi.framework.Bundle;
import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceReference;
import org.osgi.service.packageadmin.PackageAdmin;

/**
 * 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.equinox.p2.examples.rcp.prestartupdate";

	// The shared instance
	private static Activator plugin;
	
	// XXX Shared instance of bundle context
	static BundleContext bundleContext;
	
	// XXX services for starting bundles
	private static PackageAdmin packageAdmin = null;
	private static ServiceReference packageAdminRef = null;

	/**
	 * The constructor
	 */
	public Activator() {
	}

	/*
	 * (non-Javadoc)
	 * @see org.eclipse.ui.plugin.AbstractUIPlugin#start(org.osgi.framework.BundleContext)
	 */
	public void start(BundleContext context) throws Exception {
		super.start(context);
		plugin = this;
		bundleContext = context;
		
		packageAdminRef = bundleContext.getServiceReference(PackageAdmin.class.getName());
		packageAdmin = (PackageAdmin) bundleContext.getService(packageAdminRef);
	}
	
	private static Bundle getBundle(String symbolicName) {
		if (packageAdmin == null)
			return null;
		Bundle[] bundles = packageAdmin.getBundles(symbolicName, 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;
	}

	/*
	 * (non-Javadoc)
	 * @see org.eclipse.ui.plugin.AbstractUIPlugin#stop(org.osgi.framework.BundleContext)
	 */
	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 getImageDescriptor(String path) {
		return imageDescriptorFromPlugin(PLUGIN_ID, path);
	}
}