// Copyright 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.tapestry.internal.services;
import org.apache.tapestry.annotations.ApplicationState;
import org.apache.tapestry.model.MutableComponentModel;
import org.apache.tapestry.services.ApplicationStateManager;
import org.apache.tapestry.services.ClassTransformation;
import org.apache.tapestry.services.ComponentClassTransformWorker;
import org.apache.tapestry.services.TransformMethodSignature;
import static java.lang.String.format;
import java.lang.reflect.Modifier;
import java.util.List;
/**
* Looks for the {@link ApplicationState} annotation and converts read and write access on such fields into calls to the
* {@link ApplicationStateManager}.
*/
public class ApplicationStateWorker implements ComponentClassTransformWorker
{
private final ApplicationStateManager _applicationStateManager;
private final ComponentClassCache _componentClassCache;
public ApplicationStateWorker(ApplicationStateManager applicationStateManager,
ComponentClassCache componentClassCache)
{
_applicationStateManager = applicationStateManager;
_componentClassCache = componentClassCache;
}
public void transform(ClassTransformation transformation, MutableComponentModel model)
{
List<String> names = transformation.findFieldsWithAnnotation(ApplicationState.class);
if (names.isEmpty()) return;
String managerFieldName = transformation.addInjectedField(ApplicationStateManager.class,
"applicationStateManager", _applicationStateManager);
for (String fieldName : names)
{
processField(fieldName, managerFieldName, transformation);
}
}
private void processField(String fieldName, String managerFieldName, ClassTransformation transformation)
{
String fieldType = transformation.getFieldType(fieldName);
Class fieldClass = _componentClassCache.forName(fieldType);
String typeFieldName = transformation.addInjectedField(Class.class, fieldName + "_type", fieldClass);
replaceRead(transformation, fieldName, fieldType, managerFieldName, typeFieldName);
replaceWrite(transformation, fieldName, fieldType, managerFieldName, typeFieldName);
transformation.removeField(fieldName);
String booleanFieldName = fieldName + "Exists";
if (transformation.isField(booleanFieldName) && transformation.getFieldType(booleanFieldName).equals("boolean"))
{
replaceFlagRead(transformation, booleanFieldName, typeFieldName, managerFieldName);
}
}
private void replaceFlagRead(ClassTransformation transformation, String booleanFieldName, String typeFieldName,
String managerFieldName)
{
String readMethodName = transformation.newMemberName("read", booleanFieldName);
TransformMethodSignature sig = new TransformMethodSignature(Modifier.PRIVATE, "boolean", readMethodName, null,
null);
String body = format("return %s.exists(%s);", managerFieldName, typeFieldName);
transformation.addMethod(sig, body);
transformation.replaceReadAccess(booleanFieldName, readMethodName);
transformation.makeReadOnly(booleanFieldName);
transformation.removeField(booleanFieldName);
}
private void replaceWrite(ClassTransformation transformation, String fieldName, String fieldType,
String managerFieldName, String typeFieldName)
{
String writeMethodName = transformation.newMemberName("write", fieldName);
TransformMethodSignature writeSignature = new TransformMethodSignature(Modifier.PRIVATE, "void",
writeMethodName, new String[]{fieldType},
null);
String body = format("%s.set(%s, $1);", managerFieldName, typeFieldName);
transformation.addMethod(writeSignature, body);
transformation.replaceWriteAccess(fieldName, writeMethodName);
}
private void replaceRead(ClassTransformation transformation, String fieldName, String fieldType,
String managerFieldName, String typeFieldName)
{
ApplicationState annotation = transformation.getFieldAnnotation(fieldName, ApplicationState.class);
String readMethodName = transformation.newMemberName("read", fieldName);
TransformMethodSignature readMethodSignature = new TransformMethodSignature(Modifier.PRIVATE, fieldType,
readMethodName, null, null);
String methodName = annotation.create() ? "get" : "getIfExists";
String body = format("return (%s) %s.%s(%s);", fieldType, managerFieldName, methodName, typeFieldName);
transformation.addMethod(readMethodSignature, body);
transformation.replaceReadAccess(fieldName, readMethodName);
}
}