// Copyright 2004, 2005 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.enhance;
import java.lang.reflect.Modifier;
import java.util.Iterator;
import org.apache.hivemind.ErrorLog;
import org.apache.hivemind.Location;
import org.apache.hivemind.service.BodyBuilder;
import org.apache.hivemind.service.MethodSignature;
import org.apache.hivemind.util.Defense;
import org.apache.tapestry.IBinding;
import org.apache.tapestry.IComponent;
import org.apache.tapestry.binding.BindingSource;
import org.apache.tapestry.event.PageDetachListener;
import org.apache.tapestry.spec.IComponentSpecification;
import org.apache.tapestry.spec.IPropertySpecification;
/**
* Responsible for adding properties to a class corresponding to specified properties in the
* component's specification.
*
* @author Howard M. Lewis Ship
* @since 4.0
*/
public class SpecifiedPropertyWorker implements EnhancementWorker
{
private ErrorLog _errorLog;
private BindingSource _bindingSource;
/**
* Iterates over the specified properties, creating an enhanced property for each (a field, an
* accessor, a mutator). Persistent properties will invoke
* {@link org.apache.tapestry.Tapestry#fireObservedChange(IComponent, String, Object)}in thier
* mutator.
*/
public void performEnhancement(EnhancementOperation op, IComponentSpecification spec)
{
Iterator i = spec.getPropertySpecificationNames().iterator();
while (i.hasNext())
{
String name = (String) i.next();
IPropertySpecification ps = spec.getPropertySpecification(name);
try
{
performEnhancement(op, ps);
}
catch (RuntimeException ex)
{
_errorLog.error(
EnhanceMessages.errorAddingProperty(name, op.getBaseClass(), ex),
ps.getLocation(),
ex);
}
}
}
private void performEnhancement(EnhancementOperation op, IPropertySpecification ps)
{
Defense.notNull(ps, "ps");
String propertyName = ps.getName();
Class propertyType = EnhanceUtils.extractPropertyType(op, propertyName, ps.getType());
op.claimProperty(propertyName);
String field = "_$" + propertyName;
op.addField(field, propertyType);
// Release 3.0 would squack a bit about overriding non-abstract methods
// if they exist. 4.0 is less picky ... it blindly adds new methods, possibly
// overwriting methods in the base component class.
EnhanceUtils.createSimpleAccessor(op, field, propertyName, propertyType);
addMutator(op, propertyName, propertyType, field, ps.isPersistent());
String initialValue = ps.getInitialValue();
if (initialValue == null)
addReinitializer(op, propertyType, field);
else
addInitialValue(op, propertyName, propertyType, field, initialValue, ps.getLocation());
}
private void addReinitializer(EnhancementOperation op, Class propertyType, String fieldName)
{
String defaultFieldName = fieldName + "$default";
op.addField(defaultFieldName, propertyType);
// On finishLoad(), store the current value into the default field.
op.extendMethodImplementation(
IComponent.class,
EnhanceUtils.FINISH_LOAD_SIGNATURE,
defaultFieldName + " = " + fieldName + ";");
// On pageDetach(), restore the attribute to its default value.
op.extendMethodImplementation(
PageDetachListener.class,
EnhanceUtils.PAGE_DETACHED_SIGNATURE,
fieldName + " = " + defaultFieldName + ";");
}
private void addInitialValue(EnhancementOperation op, String propertyName, Class propertyType,
String fieldName, String initialValue, Location location)
{
String description = EnhanceMessages.initialValueForProperty(propertyName);
InitialValueBindingCreator creator = new InitialValueBindingCreator(_bindingSource,
description, initialValue, location);
String creatorField = op.addInjectedField(fieldName + "$initialValueBindingCreator", creator);
String bindingField = fieldName + "$initialValueBinding";
op.addField(bindingField, IBinding.class);
BodyBuilder builder = new BodyBuilder();
builder.addln("{0} = {1}.createBinding(this);", bindingField, creatorField);
op.extendMethodImplementation(IComponent.class, EnhanceUtils.FINISH_LOAD_SIGNATURE, builder
.toString());
builder.clear();
builder.addln("{0} = {1};", fieldName, EnhanceUtils.createUnwrapExpression(
op,
bindingField,
propertyType));
String code = builder.toString();
// In finishLoad() and pageDetach(), de-reference the binding to get the value
// for the property.
op.extendMethodImplementation(IComponent.class, EnhanceUtils.FINISH_LOAD_SIGNATURE, code);
op.extendMethodImplementation(
PageDetachListener.class,
EnhanceUtils.PAGE_DETACHED_SIGNATURE,
code);
}
private void addMutator(EnhancementOperation op, String propertyName, Class propertyType,
String fieldName, boolean persistent)
{
String methodName = EnhanceUtils.createMutatorMethodName(propertyName);
BodyBuilder body = new BodyBuilder();
body.begin();
if (persistent)
{
body.add("org.apache.tapestry.Tapestry#fireObservedChange(this, ");
body.addQuoted(propertyName);
body.addln(", ($w) $1);");
}
body.addln(fieldName + " = $1;");
body.end();
MethodSignature sig = new MethodSignature(void.class, methodName, new Class[]
{ propertyType }, null);
op.addMethod(Modifier.PUBLIC, sig, body.toString());
}
public void setErrorLog(ErrorLog errorLog)
{
_errorLog = errorLog;
}
public void setBindingSource(BindingSource bindingSource)
{
_bindingSource = bindingSource;
}
}