// Copyright 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.internal.services;
import static java.lang.String.format;
import java.lang.reflect.Constructor;
import java.lang.reflect.Modifier;
import org.apache.tapestry.ioc.services.ClassFab;
import org.apache.tapestry.ioc.services.ClassFactory;
import org.apache.tapestry.ioc.services.MethodSignature;
import org.apache.tapestry.services.Environment;
import org.apache.tapestry.services.EnvironmentalShadowBuilder;
public class EnvironmentalShadowBuilderImpl implements EnvironmentalShadowBuilder
{
private final ClassFactory _classFactory;
private final Environment _environment;
public EnvironmentalShadowBuilderImpl(final ClassFactory classFactory,
final Environment environment)
{
_classFactory = classFactory;
_environment = environment;
}
public <T> T build(Class<T> serviceType)
{
// TODO: Check that serviceType is an interface?
Class proxyClass = buildProxyClass(serviceType);
try
{
Constructor cons = proxyClass.getConstructors()[0];
Object raw = cons.newInstance(_environment, serviceType);
return serviceType.cast(raw);
}
catch (Exception ex)
{
throw new RuntimeException(ex);
}
}
private Class buildProxyClass(Class serviceType)
{
ClassFab classFab = _classFactory.newClass(serviceType);
classFab.addField("_environment", Environment.class);
classFab.addField("_serviceType", Class.class);
classFab.addConstructor(new Class[]
{ Environment.class, Class.class }, null, "{ _environment = $1; _serviceType = $2; }");
classFab.addMethod(Modifier.PRIVATE, new MethodSignature(serviceType, "_delegate", null,
null), "return ($r) _environment.peekRequired(_serviceType); ");
classFab.proxyMethodsToDelegate(serviceType, "_delegate()", format(
"<EnvironmentalProxy for %s>",
serviceType.getName()));
return classFab.createClass();
}
}