001 // Copyright 2008, 2009, 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.EventConstants; 018 import org.apache.tapestry5.annotations.PageActivationContext; 019 import org.apache.tapestry5.model.MutableComponentModel; 020 import org.apache.tapestry5.plastic.FieldHandle; 021 import org.apache.tapestry5.plastic.PlasticClass; 022 import org.apache.tapestry5.plastic.PlasticField; 023 import org.apache.tapestry5.runtime.Component; 024 import org.apache.tapestry5.runtime.ComponentEvent; 025 import org.apache.tapestry5.services.ComponentEventHandler; 026 import org.apache.tapestry5.services.transform.ComponentClassTransformWorker2; 027 import org.apache.tapestry5.services.transform.TransformationSupport; 028 029 import java.util.List; 030 031 /** 032 * Provides the page activation context handlers. 033 * 034 * @see org.apache.tapestry5.annotations.PageActivationContext 035 */ 036 public class PageActivationContextWorker implements ComponentClassTransformWorker2 037 { 038 public void transform(PlasticClass plasticClass, TransformationSupport support, MutableComponentModel model) 039 { 040 List<PlasticField> fields = plasticClass.getFieldsWithAnnotation(PageActivationContext.class); 041 042 switch (fields.size()) 043 { 044 case 0: 045 break; 046 047 case 1: 048 049 transformField(support, fields.get(0)); 050 051 break; 052 053 default: 054 055 throw new RuntimeException(TransformMessages.illegalNumberOfPageActivationContextHandlers2(fields)); 056 } 057 } 058 059 private void transformField(TransformationSupport support, PlasticField field) 060 { 061 PageActivationContext annotation = field.getAnnotation(PageActivationContext.class); 062 063 FieldHandle handle = field.getHandle(); 064 065 if (annotation.activate()) 066 { 067 support.addEventHandler(EventConstants.ACTIVATE, 1, 068 "PageActivationContextWorker activate event handler", 069 createActivationHandler(field.getTypeName(), handle)); 070 } 071 072 if (annotation.passivate()) 073 { 074 support.addEventHandler(EventConstants.PASSIVATE, 0, 075 "PageActivationContextWorker passivate event handler", createPassivateHandler(handle)); 076 } 077 078 // We don't claim the field, and other workers may even replace it with a FieldConduit. 079 080 } 081 082 private static ComponentEventHandler createActivationHandler(final String fieldType, final FieldHandle handle) 083 { 084 return new ComponentEventHandler() 085 { 086 public void handleEvent(Component instance, ComponentEvent event) 087 { 088 Object value = event.coerceContext(0, fieldType); 089 090 handle.set(instance, value); 091 } 092 }; 093 } 094 095 private static ComponentEventHandler createPassivateHandler(final FieldHandle handle) 096 { 097 return new ComponentEventHandler() 098 { 099 public void handleEvent(Component instance, ComponentEvent event) 100 { 101 Object value = handle.get(instance); 102 103 event.storeResult(value); 104 } 105 }; 106 } 107 }