/*
* Copyright 2013 NGDATA nv
* Copyright 2007 Outerthought bvba and Schaubroeck nv
*
* 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.lilyproject.runtime.module.javaservice;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import org.lilyproject.runtime.LilyRTException;
import org.lilyproject.runtime.module.Module;
/**
* Dynamic proxy around services exported by modules (i.e. a wrapper around
* spring beans). This has multiple purpose: provide shielding so that only service interface
* methods can be called, check that the target module is still alive (e.g. to check
* the shutdown scenario is ok), and to set the context classloader to the classloader
* of the target module.
*/
public class JavaServiceShield implements InvocationHandler {
private final Object component;
private final Module owner;
private final Class serviceType;
private final ClassLoader classLoader;
public JavaServiceShield(Object component, Module owner, Class serviceType, ClassLoader classLoader) {
this.component = component;
this.owner = owner;
this.serviceType = serviceType;
this.classLoader = classLoader;
}
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
if (!owner.isAlive()) {
throw new LilyRTException("Component belongs to module which is no longer alive, for service " + serviceType.getName());
}
Thread currentThread = Thread.currentThread();
ClassLoader previousContextClassLoader = currentThread.getContextClassLoader();
try {
currentThread.setContextClassLoader(classLoader);
return method.invoke(component, args);
} catch (InvocationTargetException e) {
throw e.getTargetException();
} finally {
currentThread.setContextClassLoader(previousContextClassLoader);
}
}
}