content: /*
   * Licensed to the Apache Software Foundation (ASF) under one
   * or more contributor license agreements.  See the NOTICE file
   * distributed with this work for additional information
   * regarding copyright ownership.  The ASF licenses this file
   * to you under the Apache License, Version 2.0 (the
   * "License"); you may not use this file except in compliance
   * with the License.  You may obtain a copy of the License at
   *
   *   http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing,
   * software distributed under the License is distributed on an
   * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
   * KIND, either express or implied.  See the License for the
   * specific language governing permissions and limitations
   * under the License.
   */
  package org.apache.aries.jmx.whiteboard;
  
  import javax.management.MBeanServer;
  
  import org.osgi.framework.BundleActivator;
  import org.osgi.framework.BundleContext;
  import org.osgi.framework.InvalidSyntaxException;
  import org.osgi.framework.ServiceReference;
  import org.osgi.util.tracker.ServiceTracker;
  
  public class Activator implements BundleActivator {
  
      private JmxWhiteboardSupport jmxWhiteBoard;
  
      private ServiceTracker mbeanServerTracker;
  
      private ServiceTracker mbeanTracker;
  
      public void start(BundleContext context) throws Exception {
          jmxWhiteBoard = new JmxWhiteboardSupport();
  
          mbeanServerTracker = new MBeanServerTracker(context);
          mbeanServerTracker.open();
  
          mbeanTracker = new MBeanTracker(context);
          mbeanTracker.open(true);
      }
  
      public void stop(BundleContext context) throws Exception {
          if (mbeanTracker != null) {
              mbeanTracker.close();
              mbeanTracker = null;
          }
  
          if (mbeanServerTracker != null) {
              mbeanServerTracker.close();
              mbeanServerTracker = null;
          }
  
          jmxWhiteBoard = null;
      }
  
      private class MBeanServerTracker extends ServiceTracker {
  
          public MBeanServerTracker(BundleContext context) {
              super(context, MBeanServer.class.getName(), null);
          }
  
          @Override
          public Object addingService(ServiceReference reference) {
              MBeanServer mbeanServer = (MBeanServer) super.addingService(reference);
              jmxWhiteBoard.addMBeanServer(mbeanServer);
              return mbeanServer;
          }
  
          @Override
          public void removedService(ServiceReference reference, Object service) {
              if (service instanceof MBeanServer) {
                  jmxWhiteBoard.removeMBeanServer((MBeanServer) service);
              }
              super.removedService(reference, service);
          }
      }
  
      private class MBeanTracker extends ServiceTracker {
  
          /**
           * Listens for any services registered with a "jmx.objectname" service
           * property. If the property is not a non-empty String object the service
           * is expected to implement the MBeanRegistration interface to create
           * the name dynamically.
           */
          private static final String SIMPLE_MBEAN_FILTER = "("
              + JmxWhiteboardSupport.PROP_OBJECT_NAME+ "=*)";
  
          public MBeanTracker(BundleContext context)
                  throws InvalidSyntaxException {
              super(context, context.createFilter(SIMPLE_MBEAN_FILTER), null);
          }
  
          @Override
          public Object addingService(ServiceReference reference) {
              Object mbean = super.addingService(reference);
              jmxWhiteBoard.registerMBean(mbean, reference);
              return mbean;
          }
  
          @Override
          public void removedService(ServiceReference reference, Object service) {
              jmxWhiteBoard.unregisterMBean(service);
              super.removedService(reference, service);
          }
      }
  }
  