// Copyright 2006, 2007 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.ioc.internal.services;
import org.apache.tapestry.ioc.services.*;
import org.apache.tapestry.ioc.util.BodyBuilder;
import org.apache.tapestry.ioc.util.StrategyRegistry;
import java.lang.reflect.Modifier;
public class StrategyBuilderImpl implements StrategyBuilder
{
private final ClassFactory _classFactory;
public StrategyBuilderImpl(@Builtin
ClassFactory classFactory)
{
_classFactory = classFactory;
}
public <S> S build(StrategyRegistry<S> registry)
{
Class<S> interfaceClass = registry.getAdapterType();
// TODO: Could cache the implClass by interfaceClass ...
Class implClass = createImplClass(interfaceClass);
try
{
Object raw = implClass.getConstructors()[0].newInstance(registry);
return interfaceClass.cast(raw);
}
catch (Exception ex)
{
throw new RuntimeException(ex);
}
}
private Class createImplClass(Class interfaceClass)
{
ClassFab cf = _classFactory.newClass(interfaceClass);
String interfaceClassName = interfaceClass.getName();
cf.addField("_registry", Modifier.PRIVATE | Modifier.FINAL, StrategyRegistry.class);
cf.addConstructor(new Class[]
{StrategyRegistry.class}, null, "_registry = $1;");
BodyBuilder builder = new BodyBuilder();
MethodIterator mi = new MethodIterator(interfaceClass);
while (mi.hasNext())
{
MethodSignature sig = mi.next();
// TODO: Checks for methods that don't have at least one parameter, or don't have a
// compatible 1st parameter. Currently, we'll get a Javassist exception.
builder.clear();
builder.begin();
builder.addln("Object selector = $1;");
builder.addln(
"%s adapter = (%<s) _registry.getByInstance(selector);",
interfaceClassName);
builder.addln("return ($r) adapter.%s($$);", sig.getName());
builder.end();
cf.addMethod(Modifier.PUBLIC, sig, builder.toString());
}
if (!mi.getToString())
cf.addToString(String.format("<Strategy for %s>", interfaceClassName));
return cf.createClass();
}
}