// Copyright 2008 The Apache Software Foundation

 //

 // Licensed 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.tapestry5.internal.transform;

 import org.apache.tapestry5.annotations.Log;

 import org.apache.tapestry5.ioc.MethodAdvice;

 import org.apache.tapestry5.ioc.internal.services.LoggingAdvice;

 import org.apache.tapestry5.ioc.services.ExceptionTracker;

 import org.apache.tapestry5.model.MutableComponentModel;

 import org.apache.tapestry5.services.*;

 import java.util.List;

 /**

  * Looks for the {@link org.apache.tapestry5.annotations.Log} marker annotation and adds method advice to perform the

  * logging. This is similar to what the {@link org.apache.tapestry5.ioc.services.LoggingDecorator} does for service

  * interface methods.

  */

 public class LogWorker implements ComponentClassTransformWorker

 {

     private final ExceptionTracker exceptionTracker;

     public LogWorker(ExceptionTracker exceptionTracker)

     {

         this.exceptionTracker = exceptionTracker;

     }

     public void transform(ClassTransformation transformation, MutableComponentModel model)

     {

         List<TransformMethodSignature> signatures = transformation.findMethodsWithAnnotation(Log.class);

         if (signatures.isEmpty()) return;

         // Re-use the logging advice from LoggingDecorator

         final MethodAdvice loggingAdvice = new LoggingAdvice(model.getLogger(), exceptionTracker);

         // ... but wrap it for use at the component level.

         ComponentMethodAdvice advice = new ComponentMethodAdvice()

         {

             public void advise(ComponentMethodInvocation invocation)

             {

                 loggingAdvice.advise(invocation);

             }

         };

         for (TransformMethodSignature signature : signatures)

             transformation.advise(signature, advice);

     }

 }