// Copyright 2007 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.internal.util.MethodInvocationBuilder;

 import org.apache.tapestry5.model.MutableComponentModel;

 import org.apache.tapestry5.services.ClassTransformation;

 import org.apache.tapestry5.services.ComponentClassTransformWorker;

 import org.apache.tapestry5.services.MethodFilter;

 import org.apache.tapestry5.services.TransformMethodSignature;

 import java.lang.annotation.Annotation;

 /**

  * Similar to {@link org.apache.tapestry5.internal.transform.RenderPhaseMethodWorker} but applies to annotations/methods

  * related to the overall page lifecycle.

  */

 public class PageLifecycleAnnotationWorker implements ComponentClassTransformWorker

 {

     private final Class<? extends Annotation> methodAnnotationClass;

     private final TransformMethodSignature lifecycleMethodSignature;

     private final String methodAlias;

     private final MethodInvocationBuilder invocationBuilder = new MethodInvocationBuilder();

     public PageLifecycleAnnotationWorker(final Class<? extends Annotation> methodAnnotationClass,

                                          final TransformMethodSignature lifecycleMethodSignature,

                                          final String methodAlias)

     {

         this.methodAnnotationClass = methodAnnotationClass;

         this.lifecycleMethodSignature = lifecycleMethodSignature;

         this.methodAlias = methodAlias;

     }

     public void transform(final ClassTransformation transformation, MutableComponentModel model)

     {

         MethodFilter filter = new MethodFilter()

         {

             public boolean accept(TransformMethodSignature signature)

             {

                 if (signature.getMethodName().equals(methodAlias))

                     return true;

                 return transformation.getMethodAnnotation(signature, methodAnnotationClass) != null;

             }

         };

         // Did this they easy way, because I doubt there will be more than one signature.

         // If I expected lots of signatures, I'd build up a BodyBuilder in the loop and extend the

         // method outside the loop.

         for (TransformMethodSignature signature : transformation.findMethods(filter))

         {

             // TODO: Filter out the non-void methods (with a non-fatal warning/error?) For the

             // moment, we just invoke the method anyway, and ignore the result. Also, MethodInvocationBuilder

             // is very forgiving (and silent) about unexpected parameters (passing null/0/false).

             String body = invocationBuilder.buildMethodInvocation(signature, transformation);

             transformation.extendMethod(lifecycleMethodSignature, body + ";");

         }

     }

 }