/*
* Copyright 2008 Tim Peierls
*
* 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.directwebremoting.guice.util;
import com.google.inject.Key;
import com.google.inject.Inject;
import com.google.inject.Injector;
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
/**
* A MethodInterceptor-decorator that looks up its target on each invocation.
*/
class InjectingMethodInterceptor implements MethodInterceptor
{
InjectingMethodInterceptor(Class<? extends MethodInterceptor> interceptorClass)
{
this.key = Key.get(interceptorClass);
}
InjectingMethodInterceptor(Key<? extends MethodInterceptor> key)
{
this.key = key;
}
@Inject void injectInterceptor(Injector newInjector)
{
this.injector = newInjector;
}
public Object invoke(MethodInvocation invocation) throws Throwable
{
Injector inj = injector; // volatile read
MethodInterceptor interceptor = inj != null ? inj.getInstance(key) : null;
if (interceptor == null)
{
return invocation.proceed();
}
else
{
return interceptor.invoke(invocation);
}
}
private final Key<? extends MethodInterceptor> key;
private volatile Injector injector = null;
}