// Copyright 2006, 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.Mixin;

 import org.apache.tapestry5.ioc.internal.util.InternalUtils;

 import org.apache.tapestry5.model.MutableComponentModel;

 import org.apache.tapestry5.services.ClassTransformation;

 import org.apache.tapestry5.services.ComponentClassResolver;

 import org.apache.tapestry5.services.ComponentClassTransformWorker;

 import org.apache.tapestry5.services.TransformConstants;

 import java.util.List;

 /**

  * Supports the {@link org.apache.tapestry5.annotations.Mixin} annotation, which allows a mixin to be part of the

  * implementation of a component. The annotation is applied to a field, which will become read-only, and contain a

  * reference to the mixin instance.

  */

 public class MixinWorker implements ComponentClassTransformWorker

 {

     private final ComponentClassResolver resolver;

     public MixinWorker(final ComponentClassResolver resolver)

     {

         this.resolver = resolver;

     }

     public void transform(ClassTransformation transformation, MutableComponentModel model)

     {

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

         for (String fieldName : fields)

         {

             Mixin annotation = transformation.getFieldAnnotation(fieldName, Mixin.class);

             transformation.claimField(fieldName, annotation);

             String mixinType = annotation.value();

             String fieldType = transformation.getFieldType(fieldName);

             String mixinClassName = InternalUtils.isBlank(mixinType) ? fieldType : resolver

                     .resolveMixinTypeToClassName(mixinType);

             model.addMixinClassName(mixinClassName);

             transformation.makeReadOnly(fieldName);

             String body = String.format("%s = (%s) %s.getMixinByClassName(\"%s\");", fieldName, fieldType,

                                         transformation.getResourcesFieldName(), mixinClassName);

             transformation

                     .extendMethod(TransformConstants.CONTAINING_PAGE_DID_LOAD_SIGNATURE, body);

         }

     }

 }