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.utils;
  
  import java.lang.reflect.Method;
  import java.util.List;
  import java.util.Map;
  
  import org.apache.aries.blueprint.services.ExtendedBlueprintContainer;
  import org.osgi.service.blueprint.container.ComponentDefinitionException;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  public class ServiceListener {
  
      private static final Logger LOGGER = LoggerFactory.getLogger(ServiceListener.class);
      
      private Object listener;
      private String registerMethod;
      private String unregisterMethod;
      private ExtendedBlueprintContainer blueprintContainer;
  
      private List<Method> registerMethods;
      private List<Method> unregisterMethods;
      private boolean initialized = false;
  
      public void setListener(Object listener) {
          this.listener = listener;
      }
  
      public void setRegisterMethod(String method) {
          this.registerMethod = method;
      }
      
      public void setUnregisterMethod(String method) {
          this.unregisterMethod = method;
      }
      
      public void setBlueprintContainer(ExtendedBlueprintContainer blueprintContainer) {
          this.blueprintContainer = blueprintContainer;
      }
      
      public void register(Object service, Map properties) {
          init(service);
          invokeMethod(registerMethods, service, properties);
      }
  
      public void unregister(Object service, Map properties) {
          init(service);
          invokeMethod(unregisterMethods, service, properties);
      }
  
      private synchronized void init(Object service) {
          if (initialized) {
              return;
          }
          Class[] paramTypes = new Class[] { service != null ? service.getClass() : null, Map.class };
          Class listenerClass = listener.getClass();
  
          if (registerMethod != null) {
              registerMethods = ReflectionUtils.findCompatibleMethods(listenerClass, registerMethod, paramTypes);
              if (registerMethods.size() == 0) {
                  throw new ComponentDefinitionException("No matching methods found for listener registration method: " + registerMethod);
              }
              LOGGER.debug("Found register methods: {}", registerMethods);
          }
          if (unregisterMethod != null) {
              unregisterMethods = ReflectionUtils.findCompatibleMethods(listenerClass, unregisterMethod, paramTypes);
              if (unregisterMethods.size() == 0) {
                  throw new ComponentDefinitionException("No matching methods found for listener unregistration method: " + unregisterMethod);
              }
              LOGGER.debug("Found unregister methods: {}", unregisterMethods);
          }
          initialized = true;
      }
  
      private void invokeMethod(List<Method> methods, Object service, Map properties) {
          if (methods == null || methods.isEmpty()) {
              return;
          }
          for (Method method : methods) {
              try {
                  ReflectionUtils.invoke(blueprintContainer.getAccessControlContext(), 
                                         method, listener, service, properties);
              } catch (Exception e) {
                  LOGGER.error("Error calling listener method " + method, e);
              }
          }
      }
  
  }
  
  