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.blueprint.compendium.cm;
  
  import java.util.Dictionary;
  import java.util.HashMap;
  import java.util.List;
  import java.util.Properties;
  import java.util.concurrent.CopyOnWriteArrayList;
  
  import org.osgi.framework.ServiceRegistration;
  import org.osgi.service.cm.ConfigurationException;
  import org.osgi.service.cm.ManagedService;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * Since persistence id can only be associated with one ManagedService in a bundle
   * this class ensures only one ManagedService is registered per persistence id.
   */
  public class ManagedObjectManager {
  
      private static final Logger LOGGER = LoggerFactory.getLogger(ManagedObjectManager.class);
  
      private HashMap<String, ConfigurationWatcher> map = new HashMap<String, ConfigurationWatcher>();
                 
      public synchronized void register(ManagedObject cm, Properties props) {
          String key = cm.getPersistentId();
          ConfigurationWatcher reg = map.get(key);
          if (reg == null) {
              reg = new ConfigurationWatcher(); 
              ServiceRegistration registration = cm.getBundle().getBundleContext().registerService(ManagedService.class.getName(), reg, (Dictionary) props);
              reg.setRegistration(registration);            
              map.put(key, reg);
          }
          reg.add(cm);
  
          try {
              Dictionary<String, Object> config = CmUtils.getProperties(reg.getRegistration().getReference(), key);
              cm.updated(config);
          } catch (Throwable t) {
              // Ignore
          }
      }
  
      public synchronized void unregister(ManagedObject cm) {
          String key = cm.getPersistentId();
          ConfigurationWatcher reg = map.get(key);
          if (reg != null) {
              reg.remove(cm);
              if (reg.isEmpty()) {
                  map.remove(key);
                  ServiceUtil.safeUnregister(reg.getRegistration());
              }
          }
      }
  
      private static class ConfigurationWatcher implements ManagedService {
  
          private ServiceRegistration registration;
          private List<ManagedObject> list = new CopyOnWriteArrayList<ManagedObject>();
          
          public ConfigurationWatcher() {
          }
          
          public void updated(final Dictionary props) throws ConfigurationException {
              // Run in a separate thread to avoid re-entrance
              new Thread() {
                  public void run() {
                      for (ManagedObject cm : list) {
                          cm.updated(props);
                      }
                  }
              }.start();
          }
          
          private void setRegistration(ServiceRegistration registration) {
              this.registration = registration;
          }
          
          private ServiceRegistration getRegistration() {
              return registration;
          }
          
          private void add(ManagedObject cm) {
              list.add(cm);
          }
          
          private void remove(ManagedObject cm) {
              list.remove(cm);
          }
          
          private boolean isEmpty() {
              return list.isEmpty();
          }
      }
          
  }
  