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.proxy;
  
  import java.io.Serializable;
  import java.lang.reflect.Method;
  
  import org.apache.aries.blueprint.Interceptor;
  import org.apache.aries.proxy.InvocationListener;
  import org.osgi.service.blueprint.reflect.ComponentMetadata;
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  /**
   * A collaborator which ensures preInvoke and postInvoke occur before and after
   * method invocation
   */
  public class SingleInterceptorCollaborator implements InvocationListener, Serializable {
  
      /** Serial version UID for this class */
      private static final long serialVersionUID = -58189302118314469L;
  
      private static final Logger LOGGER = LoggerFactory
              .getLogger(Collaborator.class);
  
      private transient Interceptor interceptor;
      private transient ComponentMetadata cm;
  
      private static final Object NON_INVOKED = new Object();
  
      public SingleInterceptorCollaborator(ComponentMetadata cm, Interceptor interceptor) {
          this.cm = cm;
          this.interceptor = interceptor;
      }
  
      /**
       * Invoke the preCall method on the interceptor
       */
      public Object preInvoke(Object o, Method m, Object[] parameters)
              throws Throwable {
          Object callToken = NON_INVOKED;
          try {
              callToken = interceptor.preCall(cm, m, parameters);
          } catch (Throwable t) {
              // using null token here to be consistent with what Collaborator does
              postInvokeExceptionalReturn(null, o, m, t);
              throw t;
          }
          return callToken;
      }
  
      /**
       * Called when the method is called and returned normally
       */
      public void postInvoke(Object token, Object o, Method method,
                             Object returnType) throws Throwable {
  
          if (token != NON_INVOKED) {
              try {
                  interceptor.postCallWithReturn(cm, method, returnType, token);
              } catch (Throwable t) {
                  LOGGER.debug("postCallInterceptorWithReturn", t);
                  throw t;
              }
          }
      }
  
      /**
       * Called when the method is called and returned with an exception
       */
      public void postInvokeExceptionalReturn(Object token, Object o, Method method,
                                              Throwable exception) throws Throwable {
          try {
              interceptor.postCallWithException(cm, method, exception, token);
          } catch (Throwable t) {
              // log the exception
              LOGGER.debug("postCallInterceptorWithException", t);
              throw t;
          }
      }
  }