/*
 * Copyright 2002-2017 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.scheduling.annotation;

import java.lang.reflect.Method;
import java.util.concurrent.Executor;

import org.springframework.aop.interceptor.AsyncExecutionInterceptor;
import org.springframework.aop.interceptor.AsyncUncaughtExceptionHandler;
import org.springframework.core.annotation.AnnotatedElementUtils;
import org.springframework.lang.Nullable;

Specialization of AsyncExecutionInterceptor that delegates method execution to an Executor based on the Async annotation. Specifically designed to support use of Async.value() executor qualification mechanism introduced in Spring 3.1.2. Supports detecting qualifier metadata via @Async at the method or declaring class level. See getExecutorQualifier(Method) for details. 
Author:
Chris Beams, Stephane Nicoll
See Also:
Async
AsyncAnnotationAdvisor
Since:
3.1.2/**
 * Specialization of {@link AsyncExecutionInterceptor} that delegates method execution to
 * an {@code Executor} based on the {@link Async} annotation. Specifically designed to
 * support use of {@link Async#value()} executor qualification mechanism introduced in
 * Spring 3.1.2. Supports detecting qualifier metadata via {@code @Async} at the method or
 * declaring class level. See {@link #getExecutorQualifier(Method)} for details.
 *
 * @author Chris Beams
 * @author Stephane Nicoll
 * @since 3.1.2
 * @see org.springframework.scheduling.annotation.Async
 * @see org.springframework.scheduling.annotation.AsyncAnnotationAdvisor
 */
public class AnnotationAsyncExecutionInterceptor extends AsyncExecutionInterceptor {

	
Create a new AnnotationAsyncExecutionInterceptor with the given executor and a simple AsyncUncaughtExceptionHandler. 
Params:
defaultExecutor – the executor to be used by default if no more specific executor has been qualified at the method level using Async.value(); as of 4.2.6, a local executor for this interceptor will be built otherwise/**
	 * Create a new {@code AnnotationAsyncExecutionInterceptor} with the given executor
	 * and a simple {@link AsyncUncaughtExceptionHandler}.
	 * @param defaultExecutor the executor to be used by default if no more specific
	 * executor has been qualified at the method level using {@link Async#value()};
	 * as of 4.2.6, a local executor for this interceptor will be built otherwise
	 */
	public AnnotationAsyncExecutionInterceptor(@Nullable Executor defaultExecutor) {
		super(defaultExecutor);
	}

	
Create a new AnnotationAsyncExecutionInterceptor with the given executor. 
Params:
defaultExecutor – the executor to be used by default if no more specific executor has been qualified at the method level using Async.value(); as of 4.2.6, a local executor for this interceptor will be built otherwise
exceptionHandler – the AsyncUncaughtExceptionHandler to use to handle exceptions thrown by asynchronous method executions with void return type/**
	 * Create a new {@code AnnotationAsyncExecutionInterceptor} with the given executor.
	 * @param defaultExecutor the executor to be used by default if no more specific
	 * executor has been qualified at the method level using {@link Async#value()};
	 * as of 4.2.6, a local executor for this interceptor will be built otherwise
	 * @param exceptionHandler the {@link AsyncUncaughtExceptionHandler} to use to
	 * handle exceptions thrown by asynchronous method executions with {@code void}
	 * return type
	 */
	public AnnotationAsyncExecutionInterceptor(@Nullable Executor defaultExecutor, AsyncUncaughtExceptionHandler exceptionHandler) {
		super(defaultExecutor, exceptionHandler);
	}


	
Return the qualifier or bean name of the executor to be used when executing the given method, specified via Async.value at the method or declaring class level. If @Async is specified at both the method and class level, the method's #value takes precedence (even if empty string, indicating that the default executor should be used preferentially). 
Params:
method – the method to inspect for executor qualifier metadata
See Also:
AsyncExecutionAspectSupport.determineAsyncExecutor(Method)
Returns:
the qualifier if specified, otherwise empty string indicating that the default executor should be used/**
	 * Return the qualifier or bean name of the executor to be used when executing the
	 * given method, specified via {@link Async#value} at the method or declaring
	 * class level. If {@code @Async} is specified at both the method and class level, the
	 * method's {@code #value} takes precedence (even if empty string, indicating that
	 * the default executor should be used preferentially).
	 * @param method the method to inspect for executor qualifier metadata
	 * @return the qualifier if specified, otherwise empty string indicating that the
	 * {@linkplain #setExecutor(Executor) default executor} should be used
	 * @see #determineAsyncExecutor(Method)
	 */
	@Override
	@Nullable
	protected String getExecutorQualifier(Method method) {
		// Maintainer's note: changes made here should also be made in
		// AnnotationAsyncExecutionAspect#getExecutorQualifier
		Async async = AnnotatedElementUtils.findMergedAnnotation(method, Async.class);
		if (async == null) {
			async = AnnotatedElementUtils.findMergedAnnotation(method.getDeclaringClass(), Async.class);
		}
		return (async != null ? async.value() : null);
	}

}