001 // Copyright 2008, 2010, 2011, 2012 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.ComponentResources;
018 import org.apache.tapestry5.annotations.InjectComponent;
019 import org.apache.tapestry5.internal.services.ComponentClassCache;
020 import org.apache.tapestry5.ioc.internal.util.InternalUtils;
021 import org.apache.tapestry5.ioc.util.UnknownValueException;
022 import org.apache.tapestry5.model.MutableComponentModel;
023 import org.apache.tapestry5.plastic.*;
024 import org.apache.tapestry5.runtime.Component;
025 import org.apache.tapestry5.services.transform.ComponentClassTransformWorker2;
026 import org.apache.tapestry5.services.transform.TransformationSupport;
027
028 /**
029 * Recognizes the {@link org.apache.tapestry5.annotations.InjectComponent} annotation, and converts the field into a
030 * read-only field containing the component. The id of the component may be explicitly stated or will be determined
031 * from the field name.
032 */
033 public class InjectComponentWorker implements ComponentClassTransformWorker2
034 {
035 private final class InjectedComponentFieldValueConduit extends ReadOnlyComponentFieldConduit
036 {
037 private final ComponentResources resources;
038
039 private final String fieldName, componentId, type;
040
041 private Component embedded;
042
043 private InjectedComponentFieldValueConduit(ComponentResources resources, String fieldName, String type,
044 String componentId)
045 {
046 super(resources, fieldName);
047
048 this.resources = resources;
049 this.fieldName = fieldName;
050 this.componentId = componentId;
051 this.type = type;
052
053 resources.getPageLifecycleCallbackHub().addPageAttachedCallback(new Runnable()
054 {
055 public void run()
056 {
057 load();
058 }
059 });
060 }
061
062 private void load()
063 {
064 try
065 {
066 embedded = resources.getEmbeddedComponent(componentId);
067 } catch (UnknownValueException ex)
068 {
069 throw new RuntimeException(String.format("Unable to inject component into field %s of class %s: %s",
070 fieldName, getComponentClassName(), ex.getMessage()), ex);
071 }
072
073 Class fieldType = classCache.forName(type);
074
075 if (!fieldType.isInstance(embedded))
076 throw new RuntimeException(
077 String
078 .format(
079 "Unable to inject component '%s' into field %s of %s. Class %s is not assignable to a field of type %s.",
080 componentId, fieldName, getComponentClassName(),
081 embedded.getClass().getName(), fieldType.getName()));
082 }
083
084 private String getComponentClassName()
085 {
086 return resources.getComponentModel().getComponentClassName();
087 }
088
089 public Object get(Object instance, InstanceContext context)
090 {
091 return embedded;
092 }
093 }
094
095 private final ComponentClassCache classCache;
096
097 public InjectComponentWorker(ComponentClassCache classCache)
098 {
099 this.classCache = classCache;
100 }
101
102 public void transform(PlasticClass plasticClass, TransformationSupport support, MutableComponentModel model)
103 {
104 for (PlasticField field : plasticClass.getFieldsWithAnnotation(InjectComponent.class))
105 {
106 InjectComponent annotation = field.getAnnotation(InjectComponent.class);
107
108 field.claim(annotation);
109
110 final String type = field.getTypeName();
111
112 final String componentId = getComponentId(field, annotation);
113
114 final String fieldName = field.getName();
115
116 ComputedValue<FieldConduit<Object>> provider = new ComputedValue<FieldConduit<Object>>()
117 {
118 public FieldConduit<Object> get(InstanceContext context)
119 {
120 ComponentResources resources = context.get(ComponentResources.class);
121
122 return new InjectedComponentFieldValueConduit(resources, fieldName, type, componentId);
123 }
124 };
125
126 field.setComputedConduit(provider);
127 }
128
129 }
130
131 private String getComponentId(PlasticField field, InjectComponent annotation)
132 {
133 String id = annotation.value();
134
135 if (InternalUtils.isNonBlank(id))
136 return id;
137
138 return InternalUtils.stripMemberName(field.getName());
139 }
140 }