// Copyright 2008, 2009 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.PageActivationContext;

 import org.apache.tapestry5.model.MutableComponentModel;

 import org.apache.tapestry5.services.ClassTransformation;

 import org.apache.tapestry5.services.ComponentClassTransformWorker;

 import org.apache.tapestry5.services.TransformMethodSignature;

 import java.lang.reflect.Modifier;

 import java.util.List;

 /**

  * Provides the page activation context handlers.  This worker must be scheduled before {@link

  * org.apache.tapestry5.internal.transform.OnEventWorker} in order for the added event handler methods to be properly

  * picked up and processed.

  *

  * @see org.apache.tapestry5.annotations.PageActivationContext

  */

 public class PageActivationContextWorker implements ComponentClassTransformWorker

 {

     public void transform(ClassTransformation transformation, MutableComponentModel model)

     {

         List<String> fields = transformation.findFieldsWithAnnotation(PageActivationContext.class);

         if (fields.size() > 1)

             throw new RuntimeException(TransformMessages.illegalNumberOfPageActivationContextHandlers(fields));

         for (String fieldName : fields)

         {

             PageActivationContext annotation = transformation.getFieldAnnotation(fieldName,

                                                                                  PageActivationContext.class);

             String fieldType = transformation.getFieldType(fieldName);

             if (annotation.activate())

             {

                 TransformMethodSignature activate

                         = new TransformMethodSignature(Modifier.PROTECTED | Modifier.FINAL, "void",

                                                        "onActivate",

                                                        new String[] { fieldType }, null);

                 transformation.addTransformedMethod(activate, fieldName + " = $1;");

             }

             if (annotation.passivate())

             {

                 TransformMethodSignature passivate

                         = new TransformMethodSignature(Modifier.PROTECTED | Modifier.FINAL, "java.lang.Object",

                                                        "onPassivate",

                                                        null, null);

                 transformation.addTransformedMethod(passivate, "return ($w) " + fieldName + ";");

             }

         }

     }

 }