001 // Copyright 2007, 2010, 2011 The Apache Software Foundation
002 //
003 // Licensed under the Apache License, Version 2.0 (the "License");
004 // you may not use this file except in compliance with the License.
005 // You may obtain a copy of the License at
006 //
007 // http://www.apache.org/licenses/LICENSE-2.0
008 //
009 // Unless required by applicable law or agreed to in writing, software
010 // distributed under the License is distributed on an "AS IS" BASIS,
011 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
012 // See the License for the specific language governing permissions and
013 // limitations under the License.
014
015 package org.apache.tapestry5.internal.transform;
016
017 import org.apache.tapestry5.func.F;
018 import org.apache.tapestry5.func.Flow;
019 import org.apache.tapestry5.func.Predicate;
020 import org.apache.tapestry5.func.Worker;
021 import org.apache.tapestry5.model.MutableComponentModel;
022 import org.apache.tapestry5.plastic.*;
023 import org.apache.tapestry5.runtime.PageLifecycleListener;
024 import org.apache.tapestry5.services.transform.ComponentClassTransformWorker2;
025 import org.apache.tapestry5.services.transform.TransformationSupport;
026
027 import java.lang.annotation.Annotation;
028
029 /**
030 * Similar to {@link org.apache.tapestry5.internal.transform.RenderPhaseMethodWorker} but applies to annotations/methods
031 * related to the overall page lifecycle. Page lifecycle methods are always void and take no parameters.
032 */
033 public class PageLifecycleAnnotationWorker implements ComponentClassTransformWorker2
034 {
035 private final Class<? extends Annotation> methodAnnotationClass;
036
037 private final MethodDescription lifecycleMethodDescription;
038
039 private final String methodAlias;
040
041 private final Predicate<PlasticMethod> MATCHER = new Predicate<PlasticMethod>()
042 {
043 public boolean accept(PlasticMethod method)
044 {
045 return method.getDescription().methodName.equalsIgnoreCase(methodAlias)
046 || method.hasAnnotation(methodAnnotationClass);
047 }
048 };
049
050 private final Worker<PlasticMethod> VALIDATE = new Worker<PlasticMethod>()
051 {
052 public void work(PlasticMethod method)
053 {
054 if (!method.isVoid())
055 throw new RuntimeException(String.format("Method %s is a lifecycle method and should return void.", method
056 .getMethodIdentifier()));
057
058 if (!method.getParameters().isEmpty())
059 throw new RuntimeException(String.format("Method %s is a lifecycle method and should take no parameters.",
060 method.getMethodIdentifier()));
061
062 }
063 };
064
065 public PageLifecycleAnnotationWorker(Class<? extends Annotation> methodAnnotationClass,
066 MethodDescription lifecycleMethodDescription, String methodAlias)
067 {
068 this.methodAnnotationClass = methodAnnotationClass;
069 this.lifecycleMethodDescription = lifecycleMethodDescription;
070 this.methodAlias = methodAlias;
071 }
072
073 public void transform(PlasticClass plasticClass, TransformationSupport support, MutableComponentModel model)
074 {
075 Flow<PlasticMethod> methods = matchLifecycleMethods(plasticClass);
076
077 if (methods.isEmpty())
078 {
079 return;
080 }
081
082 plasticClass.introduceInterface(PageLifecycleListener.class);
083
084 for (PlasticMethod method : methods)
085 {
086 invokeMethodWithinLifecycle(plasticClass, method);
087 }
088 }
089
090
091 private void invokeMethodWithinLifecycle(PlasticClass plasticClass, PlasticMethod method)
092 {
093 MethodHandle handle = method.getHandle();
094
095 plasticClass.introduceMethod(lifecycleMethodDescription).addAdvice(createAdvice(handle));
096 }
097
098 private MethodAdvice createAdvice(final MethodHandle handle)
099 {
100 return new MethodAdvice()
101 {
102 public void advise(MethodInvocation invocation)
103 {
104 invocation.proceed();
105
106 handle.invoke(invocation.getInstance()).rethrow();
107 }
108 };
109 }
110
111 private Flow<PlasticMethod> matchLifecycleMethods(PlasticClass plasticClass)
112 {
113 return F.flow(plasticClass.getMethods()).filter(MATCHER).each(VALIDATE);
114 }
115 }