AsyncAnnotationBeanPostProcessor tries to find TaskExecutor by type/name

Issue: SPR-13248

spring-context/src/main/java/org/springframework/scheduling/annotation/AsyncAnnotationBeanPostProcessor.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2014 the original author or authors.
+ * Copyright 2002-2015 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.
@@ -19,10 +19,15 @@ package org.springframework.scheduling.annotation;
 import java.lang.annotation.Annotation;
 import java.util.concurrent.Executor;
 
+import org.apache.commons.logging.Log;
+import org.apache.commons.logging.LogFactory;
+
 import org.springframework.aop.framework.AbstractAdvisingBeanPostProcessor;
 import org.springframework.aop.interceptor.AsyncUncaughtExceptionHandler;
 import org.springframework.beans.factory.BeanFactory;
 import org.springframework.beans.factory.BeanFactoryAware;
+import org.springframework.beans.factory.NoSuchBeanDefinitionException;
+import org.springframework.beans.factory.NoUniqueBeanDefinitionException;
 import org.springframework.core.task.TaskExecutor;
 import org.springframework.util.Assert;
 
@@ -54,10 +59,21 @@ import org.springframework.util.Assert;
  * @see Async
  * @see AsyncAnnotationAdvisor
  * @see #setBeforeExistingAdvisors
+ * @see ScheduledAnnotationBeanPostProcessor
  */
 @SuppressWarnings("serial")
 public class AsyncAnnotationBeanPostProcessor extends AbstractAdvisingBeanPostProcessor implements BeanFactoryAware {
 
+	/**
+	 * The default name of the {@link TaskExecutor} bean to pick up: "taskExecutor".
+	 * <p>Note that the initial lookup happens by type; this is just the fallback
+	 * in case of multiple executor beans found in the context.
+	 */
+	public static final String DEFAULT_TASK_EXECUTOR_BEAN_NAME = "taskExecutor";
+
+
+	protected final Log logger = LogFactory.getLog(getClass());
+
 	private Class<? extends Annotation> asyncAnnotationType;
 
 	private Executor executor;
@@ -100,9 +116,35 @@ public class AsyncAnnotationBeanPostProcessor extends AbstractAdvisingBeanPostPr
 		this.exceptionHandler = exceptionHandler;
 	}
 
+
 	@Override
 	public void setBeanFactory(BeanFactory beanFactory) {
-		AsyncAnnotationAdvisor advisor =  new AsyncAnnotationAdvisor(this.executor, this.exceptionHandler);
+		Executor executorToUse = this.executor;
+		if (executorToUse == null) {
+			try {
+				// Search for TaskExecutor bean... not plain Executor since that would
+				// match with ScheduledExecutorService as well, which is unusable for
+				// our purposes here. TaskExecutor is more clearly designed for it.
+				executorToUse = beanFactory.getBean(TaskExecutor.class);
+			}
+			catch (NoUniqueBeanDefinitionException ex) {
+				try {
+					executorToUse = beanFactory.getBean(DEFAULT_TASK_EXECUTOR_BEAN_NAME, TaskExecutor.class);
+				}
+				catch (NoSuchBeanDefinitionException ex2) {
+					throw new IllegalStateException("More than one TaskExecutor bean exists within the context, " +
+							"and none is named 'taskExecutor'. Mark one of them as primary or name it " +
+							"'taskExecutor' (possibly as an alias); or specify the AsyncConfigurer interface " +
+							"and implement getAsyncExecutor() accordingly.", ex);
+				}
+			}
+			catch (NoSuchBeanDefinitionException ex) {
+				logger.debug("Could not find default TaskExecutor bean", ex);
+				// Giving up -> falling back to default executor within the advisor...
+			}
+		}
+
+		AsyncAnnotationAdvisor advisor =  new AsyncAnnotationAdvisor(executorToUse, this.exceptionHandler);
 		if (this.asyncAnnotationType != null) {
 			advisor.setAsyncAnnotationType(this.asyncAnnotationType);
 		}

spring-context/src/main/java/org/springframework/scheduling/annotation/ScheduledAnnotationBeanPostProcessor.java

@@ -82,13 +82,14 @@ import org.springframework.util.StringValueResolver;
  * @see SchedulingConfigurer
  * @see org.springframework.scheduling.TaskScheduler
  * @see org.springframework.scheduling.config.ScheduledTaskRegistrar
+ * @see AsyncAnnotationBeanPostProcessor
  */
 public class ScheduledAnnotationBeanPostProcessor implements BeanPostProcessor, Ordered,
 		EmbeddedValueResolverAware, BeanFactoryAware, ApplicationContextAware,
 		SmartInitializingSingleton, ApplicationListener<ContextRefreshedEvent>, DisposableBean {
 
 	/**
-	 * The default name of the TaskScheduler bean to pick up: "taskScheduler".
+	 * The default name of the {@link TaskScheduler} bean to pick up: "taskScheduler".
 	 * <p>Note that the initial lookup happens by type; this is just the fallback
 	 * in case of multiple scheduler beans found in the context.
 	 */