// Copyright 2006, 2007, 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.InjectPage;

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

 import org.apache.tapestry5.ioc.util.BodyBuilder;

 import org.apache.tapestry5.model.MutableComponentModel;

 import org.apache.tapestry5.services.*;

 import java.lang.reflect.Modifier;

 import java.util.List;

 /**

  * Peforms transformations that allow pages to be injected into components.

  *

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

  */

 public class InjectPageWorker implements ComponentClassTransformWorker

 {

     private final ComponentSource componentSource;

     private final ComponentClassResolver resolver;

     public InjectPageWorker(ComponentSource componentSource, ComponentClassResolver resolver)

     {

         this.componentSource = componentSource;

         this.resolver = resolver;

     }

     public void transform(ClassTransformation transformation, MutableComponentModel model)

     {

         List<String> names = transformation.findFieldsWithAnnotation(InjectPage.class);

         if (names.isEmpty()) return;

         String componentSource = transformation.addInjectedField(ComponentSource.class, "componentSource",

                                                                  this.componentSource);

         for (String name : names)

             addInjectedPage(transformation, name, componentSource);

     }

     private void addInjectedPage(ClassTransformation transformation, String fieldName, String componentSource)

     {

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

         transformation.claimField(fieldName, annotation);

         String pageName = annotation.value();

         String fieldType = transformation.getFieldType(fieldName);

         String methodName = transformation.newMemberName("read_inject_page", fieldName);

         String injectedPageName = InternalUtils.isBlank(pageName) ? resolver

                 .resolvePageClassNameToPageName(fieldType) : pageName;

         TransformMethodSignature sig = new TransformMethodSignature(Modifier.PRIVATE, fieldType, methodName, null,

                                                                     null);

         BodyBuilder builder = new BodyBuilder();

         builder.begin();

         builder.addln("return (%s) %s.getPage(\"%s\");", fieldType, componentSource, injectedPageName);

         builder.end();

         transformation.addMethod(sig, builder.toString());

         transformation.replaceReadAccess(fieldName, methodName);

         transformation.makeReadOnly(fieldName);

         transformation.removeField(fieldName);

     }

 }