001    // Copyright 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    
014    package org.apache.tapestry5.internal.transform;
015    
016    import org.apache.tapestry5.ComponentResources;
017    import org.apache.tapestry5.annotations.DiscardAfter;
018    import org.apache.tapestry5.model.MutableComponentModel;
019    import org.apache.tapestry5.plastic.MethodAdvice;
020    import org.apache.tapestry5.plastic.MethodInvocation;
021    import org.apache.tapestry5.plastic.PlasticClass;
022    import org.apache.tapestry5.plastic.PlasticMethod;
023    import org.apache.tapestry5.services.transform.ComponentClassTransformWorker2;
024    import org.apache.tapestry5.services.transform.TransformationSupport;
025    
026    public class DiscardAfterWorker implements ComponentClassTransformWorker2
027    {
028        private static final MethodAdvice advice = new MethodAdvice()
029        {
030            public void advise(MethodInvocation invocation)
031            {
032                invocation.proceed();
033    
034                if (invocation.didThrowCheckedException())
035                    return;
036    
037                ComponentResources resources = invocation.getInstanceContext().get(ComponentResources.class);
038    
039                resources.discardPersistentFieldChanges();
040            }
041        };
042    
043        public void transform(PlasticClass plasticClass, TransformationSupport support, MutableComponentModel model)
044        {
045            for (PlasticMethod method : plasticClass.getMethodsWithAnnotation(DiscardAfter.class))
046            {
047                method.addAdvice(advice);
048            }
049        }
050    }