org.eclipse.gemini.web.extender/src/main/java/org/eclipse/gemini/web/extender/ExtenderActivator.java

/*******************************************************************************
 * Copyright (c) 2009, 2017 VMware Inc.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * and Apache License v2.0 which accompanies this distribution. 
 * The Eclipse Public License is available at
 *   http://www.eclipse.org/legal/epl-v10.html
 * and the Apache License v2.0 is available at 
 *   http://www.opensource.org/licenses/apache2.0.php.
 * You may elect to redistribute this code under either of these licenses.  
 *
 * Contributors:
 *   VMware Inc. - initial contribution
 *******************************************************************************/

package org.eclipse.gemini.web.extender;

import org.eclipse.gemini.web.core.WebContainer;
import org.osgi.framework.Bundle;
import org.osgi.framework.BundleActivator;
import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceReference;
import org.osgi.util.tracker.BundleTracker;
import org.osgi.util.tracker.ServiceTracker;
import org.osgi.util.tracker.ServiceTrackerCustomizer;

public final class ExtenderActivator implements BundleActivator {

    private ServiceTracker<WebContainer, String> serviceTracker;

    @Override
    public void start(BundleContext context) {
        this.serviceTracker = new ServiceTracker<>(context, WebContainer.class, new ExtendedWebContainerTracker(context));
        this.serviceTracker.open();
    }

    @Override
    public void stop(BundleContext context) {
        this.serviceTracker.close();
    }

    private static final class ExtendedWebContainerTracker implements ServiceTrackerCustomizer<WebContainer, String> {

        private final BundleContext context;

        private BundleTracker<Object> bundleTracker;

        public ExtendedWebContainerTracker(BundleContext context) {
            this.context = context;
        }

        @Override
        public String addingService(ServiceReference<WebContainer> reference) {
            if (this.bundleTracker == null) {
                final Bundle systemBundle = this.context.getBundle(0);
                this.bundleTracker = new BundleTracker<>(systemBundle.getBundleContext(), Bundle.ACTIVE,
                        new WebContainerBundleCustomizer(this.context.getService(reference), this.context.getBundle()));
            }
            this.bundleTracker.open();
            return reference.getBundle().getSymbolicName();
        }

        @Override
        public void modifiedService(ServiceReference<WebContainer> reference, String service) {
        }

        @Override
        public void removedService(ServiceReference<WebContainer> reference, String service) {
            this.bundleTracker.close();
            this.bundleTracker = null;
        }

    }

}