/*
* Copyright 2012-2014 Amazon.com, Inc. or its affiliates. All Rights Reserved.
*
* Licensed under the Apache License, Version 2.0 (the "License"). You may not
* use this file except in compliance with the License. A copy of the License is
* located at
*
* http://aws.amazon.com/apache2.0
*
* or in the "license" file accompanying this file. This file 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 com.amazonaws.services.simpleworkflow.flow.interceptors;
import java.lang.reflect.InvocationHandler;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Proxy;
import com.amazonaws.services.simpleworkflow.flow.DecisionContextProviderImpl;
import com.amazonaws.services.simpleworkflow.flow.WorkflowClock;
import com.amazonaws.services.simpleworkflow.flow.core.Settable;
import com.amazonaws.services.simpleworkflow.flow.core.TryFinally;
/**
* Repeats every call to a wrapped object method according to provided schedule.
* If {@link RetryPolicy} is provided calls that fail are retried according to
* it. Retry count is reset at each scheduled invocation.
*
* @author fateev
*/
public class ScheduleDecorator implements Decorator {
private final class DecoratorInvocationHandler implements InvocationHandler {
private final Object object;
public DecoratorInvocationHandler(Object object) {
this.object = object;
}
@Override
public Object invoke(Object proxy, final Method method, final Object[] args) throws Throwable {
try {
if (!isDecorated(method, args)) {
return method.invoke(object, args);
}
}
catch (InvocationTargetException ite) {
throw ite.getTargetException();
}
Class<?> returnType = method.getReturnType();
boolean isVoidReturnType = Void.TYPE.equals(returnType);
final Settable<Object> result = isVoidReturnType ? null : new Settable<Object>();
new TryFinally() {
Object r;
@Override
protected void doTry() throws Throwable {
scheduledExecutor.execute(new AsyncRunnable() {
@Override
public void run() throws Throwable {
try {
r = method.invoke(object, args);
}
catch (InvocationTargetException ite) {
throw ite.getTargetException();
}
}
});
}
@Override
protected void doFinally() throws Throwable {
if (result != null) {
result.set(r);
}
}
};
return result;
}
}
private final AsyncScheduledExecutor scheduledExecutor;
public ScheduleDecorator(InvocationSchedule schedule, WorkflowClock clock) {
scheduledExecutor = new AsyncScheduledExecutor(schedule, clock);
}
public ScheduleDecorator(InvocationSchedule schedule) {
this(schedule, new DecisionContextProviderImpl().getDecisionContext().getWorkflowClock());
}
@SuppressWarnings("unchecked")
@Override
public final <V> V decorate(Class<V> interfaces, V object) {
Class<?>[] interfazes = { interfaces };
return (V) Proxy.newProxyInstance(object.getClass().getClassLoader(), interfazes, new DecoratorInvocationHandler(object));
}
@SuppressWarnings("unchecked")
@Override
public final <V> V decorate(Class<?>[] interfaces, V object) {
return (V) Proxy.newProxyInstance(object.getClass().getClassLoader(), interfaces, new DecoratorInvocationHandler(object));
}
private boolean isDecorated(Method method, Object[] args) {
return !method.getDeclaringClass().equals(Object.class);
}
}