EnableAspectJAutoProxy features exposeProxy flag (analogous to XML namespace)

Issue: SPR-10454

Author: jhoeller

spring-aop/src/main/java/org/springframework/aop/config/AopConfigUtils.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2012 the original author or authors.
+ * 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.
@@ -97,7 +97,7 @@ public static void forceAutoProxyCreatorToUseClassProxying(BeanDefinitionRegistr
 		}
 	}
 
-	static void forceAutoProxyCreatorToExposeProxy(BeanDefinitionRegistry registry) {
+	public static void forceAutoProxyCreatorToExposeProxy(BeanDefinitionRegistry registry) {
 		if (registry.containsBeanDefinition(AUTO_PROXY_CREATOR_BEAN_NAME)) {
 			BeanDefinition definition = registry.getBeanDefinition(AUTO_PROXY_CREATOR_BEAN_NAME);
 			definition.getPropertyValues().add("exposeProxy", Boolean.TRUE);

spring-context/src/main/java/org/springframework/context/annotation/AspectJAutoProxyRegistrar.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2002-2013 the original author or authors.
+ * 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.
@@ -27,6 +27,7 @@
  * as appropriate based on a given @{@link EnableAspectJAutoProxy} annotation.
  *
  * @author Chris Beams
+ * @author Juergen Hoeller
  * @since 3.1
  * @see EnableAspectJAutoProxy
  */
@@ -43,11 +44,14 @@ public void registerBeanDefinitions(
 
 		AopConfigUtils.registerAspectJAnnotationAutoProxyCreatorIfNecessary(registry);
 
-		AnnotationAttributes enableAJAutoProxy =
+		AnnotationAttributes enableAspectJAutoProxy =
 				AnnotationConfigUtils.attributesFor(importingClassMetadata, EnableAspectJAutoProxy.class);
-		if (enableAJAutoProxy.getBoolean("proxyTargetClass")) {
+		if (enableAspectJAutoProxy.getBoolean("proxyTargetClass")) {
 			AopConfigUtils.forceAutoProxyCreatorToUseClassProxying(registry);
 		}
+		if (enableAspectJAutoProxy.getBoolean("exposeProxy")) {
+			AopConfigUtils.forceAutoProxyCreatorToExposeProxy(registry);
+		}
 	}
 
 }

spring-context/src/main/java/org/springframework/context/annotation/EnableAspectJAutoProxy.java

@@ -102,6 +102,7 @@
  * }</pre>
  *
  * @author Chris Beams
+ * @author Juergen Hoeller
  * @since 3.1
  * @see org.aspectj.lang.annotation.Aspect
  */
@@ -117,4 +118,12 @@
 	 */
 	boolean proxyTargetClass() default false;
 
+	/**
+	 * Indicate that the proxy should be exposed by the AOP framework as a {@code ThreadLocal}
+	 * for retrieval via the {@link org.springframework.aop.framework.AopContext} class.
+	 * Off by default, i.e. no guarantees that {@code AopContext} access will work.
+	 * @since 4.3.1
+	 */
+	boolean exposeProxy() default false;
+
 }

spring-context/src/test/java/org/springframework/context/annotation/EnableAspectJAutoProxyTests.java

@@ -20,11 +20,13 @@
 import java.lang.annotation.RetentionPolicy;
 
 import example.scannable.FooService;
+import example.scannable.FooServiceImpl;
 import example.scannable.ServiceInvocationCounter;
 import org.aspectj.lang.annotation.Aspect;
 import org.aspectj.lang.annotation.Before;
 import org.junit.Test;
 
+import org.springframework.aop.framework.AopContext;
 import org.springframework.aop.support.AopUtils;
 import org.springframework.context.ApplicationContext;
 import org.springframework.context.ConfigurableApplicationContext;
@@ -54,6 +56,14 @@ public void withCglibProxy() {
 		assertThat(AopUtils.isCglibProxy(ctx.getBean(FooService.class)), is(true));
 	}
 
+	@Test
+	public void withExposedProxy() {
+		ApplicationContext ctx = new AnnotationConfigApplicationContext(ConfigWithExposedProxy.class);
+
+		aspectIsApplied(ctx);
+		assertThat(AopUtils.isJdkDynamicProxy(ctx.getBean(FooService.class)), is(true));
+	}
+
 	private void aspectIsApplied(ApplicationContext ctx) {
 		FooService fooService = ctx.getBean(FooService.class);
 		ServiceInvocationCounter counter = ctx.getBean(ServiceInvocationCounter.class);
@@ -101,23 +111,44 @@ public void withAnnotationOnArgumentAndCglibProxy() {
 	static class ConfigWithJdkProxy {
 	}
 
+
 	@ComponentScan("example.scannable")
 	@EnableAspectJAutoProxy(proxyTargetClass = true)
 	static class ConfigWithCglibProxy {
 	}
 
 
+	@ComponentScan("example.scannable")
+	@EnableAspectJAutoProxy(exposeProxy = true)
+	static class ConfigWithExposedProxy {
+
+		@Bean
+		public FooService fooServiceImpl() {
+			return new FooServiceImpl() {
+				@Override
+				public String foo(int id) {
+					assertNotNull(AopContext.currentProxy());
+					return super.foo(id);
+				}
+			};
+		}
+	}
+
+
 	@Retention(RetentionPolicy.RUNTIME)
 	public @interface Loggable {
 	}
 
+
 	@Loggable
 	public static class SampleDto {
 	}
 
+
 	public static class SampleInputBean {
 	}
 
+
 	public static class SampleService {
 
 		// Not matched method on {@link LoggingAspect}.
@@ -129,6 +160,7 @@ public void execute(SampleDto dto) {
 		}
 	}
 
+
 	@Aspect
 	public static class LoggingAspect {