// Copyright 2006, 2007, 2008, 2011 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.ioc.internal.services;
import java.lang.reflect.Method;
import java.util.Map;
import org.apache.tapestry5.ioc.services.Builtin;
import org.apache.tapestry5.ioc.services.PlasticProxyFactory;
import org.apache.tapestry5.ioc.services.StrategyBuilder;
import org.apache.tapestry5.ioc.util.StrategyRegistry;
import org.apache.tapestry5.plastic.ClassInstantiator;
import org.apache.tapestry5.plastic.InstructionBuilder;
import org.apache.tapestry5.plastic.InstructionBuilderCallback;
import org.apache.tapestry5.plastic.MethodDescription;
import org.apache.tapestry5.plastic.PlasticClass;
import org.apache.tapestry5.plastic.PlasticClassTransformer;
import org.apache.tapestry5.plastic.PlasticField;
public class StrategyBuilderImpl implements StrategyBuilder
{
private final PlasticProxyFactory proxyFactory;
public StrategyBuilderImpl(@Builtin
PlasticProxyFactory proxyFactory)
{
this.proxyFactory = proxyFactory;
}
@Override
public <S> S build(StrategyRegistry<S> registry)
{
return createProxy(registry.getAdapterType(), registry);
}
@Override
public <S> S build(Class<S> adapterType, Map<Class, S> registrations)
{
StrategyRegistry<S> registry = StrategyRegistry.newInstance(adapterType, registrations);
return build(registry);
}
private <S> S createProxy(final Class<S> interfaceType, final StrategyRegistry<S> registry)
{
ClassInstantiator instantiator = proxyFactory.createProxy(interfaceType, new PlasticClassTransformer()
{
@Override
public void transform(PlasticClass plasticClass)
{
final PlasticField registryField = plasticClass.introduceField(StrategyRegistry.class, "registry")
.inject(registry);
for (final Method method : interfaceType.getMethods())
{
plasticClass.introduceMethod(new MethodDescription(method), new InstructionBuilderCallback()
{
@Override
public void doBuild(InstructionBuilder builder)
{
Class returnType = method.getReturnType();
builder.loadThis().getField(registryField);
// Argument 0 is the selector used to find the adapter and should be an object reference,
// not a primitive.
builder.loadArgument(0);
// Use the StrategyRegistry to get the adapter to re-invoke the method on
builder.invoke(StrategyRegistry.class, Object.class, "getByInstance", Object.class)
.checkcast(interfaceType);
// That leaves the correct adapter on top of the stack. Get the
// selector and the rest of the arguments in place and invoke the method.
builder.loadArguments().invoke(interfaceType, returnType, method.getName(),
method.getParameterTypes());
builder.returnResult();
}
});
}
plasticClass.addToString(String.format("<Strategy for %s>", interfaceType.getName()));
}
});
return interfaceType.cast(instantiator.newInstance());
}
}