// Copyright 2006, 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.tapestry5.internal.transform;
import org.apache.tapestry5.annotations.Persist;
import org.apache.tapestry5.ioc.util.BodyBuilder;
import org.apache.tapestry5.model.MutableComponentModel;
import org.apache.tapestry5.services.*;
import static java.lang.String.format;
import java.lang.reflect.Modifier;
/**
* Converts fields with the {@link org.apache.tapestry5.annotations.Persist} annotation into persistent fields.
*/
public class PersistWorker implements ComponentClassTransformWorker
{
public void transform(ClassTransformation transformation, MutableComponentModel model)
{
for (String name : transformation.findFieldsWithAnnotation(Persist.class))
{
makeFieldPersistent(name, transformation, model);
}
}
/**
* Making a field persistent: <ul> <li>Need a secondary default field that stores the initial value</li> <li>Store
* the active value into the default field when the page finishes loading</li> <li>Roll the active value back to the
* default when the page detaches</li> <ii>On changes to the active field, post the change via the {@link
* org.apache.tapestry5.internal.InternalComponentResources} </li> <li>When the page attaches, pull the persisted
* value for the field out of the {@link org.apache.tapestry5.services.PersistentFieldBundle}</li> </ul>
*/
private void makeFieldPersistent(String fieldName, ClassTransformation transformation,
MutableComponentModel model)
{
String fieldType = transformation.getFieldType(fieldName);
Persist annotation = transformation.getFieldAnnotation(fieldName, Persist.class);
transformation.claimField(fieldName, annotation);
// Record the type of persistence, until needed later.
String logicalFieldName = model.setFieldPersistenceStrategy(fieldName, annotation.value());
String defaultFieldName = transformation.addField(Modifier.PRIVATE, fieldType, fieldName
+ "_default");
transformation.extendMethod(TransformConstants.CONTAINING_PAGE_DID_LOAD_SIGNATURE, format(
"%s = %s;",
defaultFieldName,
fieldName));
transformation.extendMethod(
TransformConstants.CONTAINING_PAGE_DID_DETACH_SIGNATURE,
format("%s = %s;", fieldName, defaultFieldName));
String resourcesFieldName = transformation.getResourcesFieldName();
String writeMethodName = transformation.newMemberName("write", fieldName);
BodyBuilder builder = new BodyBuilder();
builder.begin();
builder.addln(
"%s.persistFieldChange(\"%s\", ($w) $1);",
resourcesFieldName,
logicalFieldName);
builder.addln("%s = $1;", fieldName);
builder.end();
transformation.addMethod(new TransformMethodSignature(Modifier.PRIVATE, "void", writeMethodName,
new String[]
{ fieldType }, null), builder.toString());
transformation.replaceWriteAccess(fieldName, writeMethodName);
builder.clear();
builder.begin();
// Check to see if there's a recorded change for this component, this field.
builder.addln("if (%s.hasFieldChange(\"%s\"))", resourcesFieldName, logicalFieldName);
String wrapperType = TransformUtils.getWrapperTypeName(fieldType);
// Get the value, cast it to the correct type (or wrapper type)
builder.add(
" %s = ((%s) %s.getFieldChange(\"%s\"))",
fieldName,
wrapperType,
resourcesFieldName,
logicalFieldName);
// For primtive types, add in the method call to unwrap the wrapper type to a primitive type
String unwrapMethodName = TransformUtils.getUnwrapperMethodName(fieldType);
if (unwrapMethodName == null)
builder.addln(";");
else
builder.addln(".%s();", unwrapMethodName);
builder.end();
transformation.extendMethod(
TransformConstants.CONTAINING_PAGE_DID_ATTACH_SIGNATURE,
builder.toString());
}
}