/*
* Copyright 2002-2016 the original author or authors.
*
* 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.springframework.aop.interceptor;
import java.lang.reflect.Method;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Executor;
import java.util.concurrent.Future;
import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
import org.springframework.aop.support.AopUtils;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.core.BridgeMethodResolver;
import org.springframework.core.Ordered;
import org.springframework.core.task.AsyncTaskExecutor;
import org.springframework.core.task.SimpleAsyncTaskExecutor;
import org.springframework.util.ClassUtils;
/**
* AOP Alliance {@code MethodInterceptor} that processes method invocations
* asynchronously, using a given {@link org.springframework.core.task.AsyncTaskExecutor}.
* Typically used with the {@link org.springframework.scheduling.annotation.Async} annotation.
*
* <p>In terms of target method signatures, any parameter types are supported.
* However, the return type is constrained to either {@code void} or
* {@code java.util.concurrent.Future}. In the latter case, the Future handle
* returned from the proxy will be an actual asynchronous Future that can be used
* to track the result of the asynchronous method execution. However, since the
* target method needs to implement the same signature, it will have to return
* a temporary Future handle that just passes the return value through
* (like Spring's {@link org.springframework.scheduling.annotation.AsyncResult}
* or EJB 3.1's {@code javax.ejb.AsyncResult}).
*
* <p>When the return type is {@code java.util.concurrent.Future}, any exception thrown
* during the execution can be accessed and managed by the caller. With {@code void}
* return type however, such exceptions cannot be transmitted back. In that case an
* {@link AsyncUncaughtExceptionHandler} can be registered to process such exceptions.
*
* <p>As of Spring 3.1.2 the {@code AnnotationAsyncExecutionInterceptor} subclass is
* preferred for use due to its support for executor qualification in conjunction with
* Spring's {@code @Async} annotation.
*
* @author Juergen Hoeller
* @author Chris Beams
* @author Stephane Nicoll
* @since 3.0
* @see org.springframework.scheduling.annotation.Async
* @see org.springframework.scheduling.annotation.AsyncAnnotationAdvisor
* @see org.springframework.scheduling.annotation.AnnotationAsyncExecutionInterceptor
*/
public class AsyncExecutionInterceptor extends AsyncExecutionAspectSupport implements MethodInterceptor, Ordered {
/**
* Create a new instance with a default {@link AsyncUncaughtExceptionHandler}.
* @param defaultExecutor the {@link Executor} (typically a Spring {@link AsyncTaskExecutor}
* or {@link java.util.concurrent.ExecutorService}) to delegate to;
* as of 4.2.6, a local executor for this interceptor will be built otherwise
*/
public AsyncExecutionInterceptor(Executor defaultExecutor) {
super(defaultExecutor);
}
/**
* Create a new {@code AsyncExecutionInterceptor}.
* @param defaultExecutor the {@link Executor} (typically a Spring {@link AsyncTaskExecutor}
* or {@link java.util.concurrent.ExecutorService}) to delegate to;
* as of 4.2.6, a local executor for this interceptor will be built otherwise
* @param exceptionHandler the {@link AsyncUncaughtExceptionHandler} to use
*/
public AsyncExecutionInterceptor(Executor defaultExecutor, AsyncUncaughtExceptionHandler exceptionHandler) {
super(defaultExecutor, exceptionHandler);
}
/**
* Intercept the given method invocation, submit the actual calling of the method to
* the correct task executor and return immediately to the caller.
* @param invocation the method to intercept and make asynchronous
* @return {@link Future} if the original method returns {@code Future}; {@code null}
* otherwise.
*/
@Override
public Object invoke(final MethodInvocation invocation) throws Throwable {
Class<?> targetClass = (invocation.getThis() != null ? AopUtils.getTargetClass(invocation.getThis()) : null);
Method specificMethod = ClassUtils.getMostSpecificMethod(invocation.getMethod(), targetClass);
final Method userDeclaredMethod = BridgeMethodResolver.findBridgedMethod(specificMethod);
AsyncTaskExecutor executor = determineAsyncExecutor(userDeclaredMethod);
if (executor == null) {
throw new IllegalStateException(
"No executor specified and no default executor set on AsyncExecutionInterceptor either");
}
Callable<Object> task = new Callable<Object>() {
@Override
public Object call() throws Exception {
try {
Object result = invocation.proceed();
if (result instanceof Future) {
return ((Future<?>) result).get();
}
}
catch (ExecutionException ex) {
handleError(ex.getCause(), userDeclaredMethod, invocation.getArguments());
}
catch (Throwable ex) {
handleError(ex, userDeclaredMethod, invocation.getArguments());
}
return null;
}
};
return doSubmit(task, executor, invocation.getMethod().getReturnType());
}
/**
* This implementation is a no-op for compatibility in Spring 3.1.2.
* Subclasses may override to provide support for extracting qualifier information,
* e.g. via an annotation on the given method.
* @return always {@code null}
* @since 3.1.2
* @see #determineAsyncExecutor(Method)
*/
@Override
protected String getExecutorQualifier(Method method) {
return null;
}
/**
* This implementation searches for a unique {@link org.springframework.core.task.TaskExecutor}
* bean in the context, or for an {@link Executor} bean named "taskExecutor" otherwise.
* If neither of the two is resolvable (e.g. if no {@code BeanFactory} was configured at all),
* this implementation falls back to a newly created {@link SimpleAsyncTaskExecutor} instance
* for local use if no default could be found.
* @see #DEFAULT_TASK_EXECUTOR_BEAN_NAME
*/
@Override
protected Executor getDefaultExecutor(BeanFactory beanFactory) {
Executor defaultExecutor = super.getDefaultExecutor(beanFactory);
return (defaultExecutor != null ? defaultExecutor : new SimpleAsyncTaskExecutor());
}
@Override
public int getOrder() {
return Ordered.HIGHEST_PRECEDENCE;
}
}