From a0349e49dd0b4ac7e2df06eaa8b06e403b67c748 Mon Sep 17 00:00:00 2001
From: Sam Brannen <sbrannen@pivotal.io>
Date: Fri, 8 Mar 2019 16:14:20 +0100
Subject: [PATCH] [WIP] Playground for gh-22541

---
 .../test/BeanMethodAnnotationLookupTests.java | 109 ++++++++++++++++++
 1 file changed, 109 insertions(+)
 create mode 100644 spring-test/src/test/java/org/springframework/test/BeanMethodAnnotationLookupTests.java

diff --git a/spring-test/src/test/java/org/springframework/test/BeanMethodAnnotationLookupTests.java b/spring-test/src/test/java/org/springframework/test/BeanMethodAnnotationLookupTests.java
new file mode 100644
index 000000000000..4dc3215df6bc
--- /dev/null
+++ b/spring-test/src/test/java/org/springframework/test/BeanMethodAnnotationLookupTests.java
@@ -0,0 +1,109 @@
+
+package org.springframework.test;
+
+import java.lang.annotation.Annotation;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+import java.lang.reflect.Method;
+import java.util.Arrays;
+
+import org.junit.jupiter.api.Test;
+
+import org.springframework.beans.BeansException;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.config.BeanDefinition;
+import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
+import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
+import org.springframework.beans.factory.support.AbstractBeanDefinition;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.core.annotation.AnnotatedElementUtils;
+import org.springframework.test.context.junit.jupiter.SpringJUnitConfig;
+import org.springframework.util.ClassUtils;
+import org.springframework.util.ReflectionUtils;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+@SpringJUnitConfig
+public class BeanMethodAnnotationLookupTests {
+
+	@Autowired
+	String foo;
+
+	@Autowired
+	String bar;
+
+
+	@Test
+	void test() {
+		assertEquals("foo", this.foo);
+		assertEquals("bar", this.bar);
+	}
+
+
+	@Configuration
+	static class Config {
+
+		@MyAnnotation
+		@Bean
+		String foo() {
+			return "foo";
+		}
+
+		@Bean
+		String bar() {
+			return "bar";
+		}
+
+		@Bean
+		static BeanFactoryPostProcessor myBeanFactoryPostProcessor() {
+			return new MyBeanFactoryPostProcessor();
+		}
+
+	}
+
+	static class MyBeanFactoryPostProcessor implements BeanFactoryPostProcessor {
+
+		@Override
+		public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
+			Class<? extends Annotation> annotationType = MyAnnotation.class;
+
+			Arrays.stream(beanFactory.getBeanDefinitionNames())//
+					.map(beanFactory::getBeanDefinition)//
+					.filter(bd -> !bd.isAbstract())//
+					.filter(bd -> bd.getFactoryMethodName() != null)//
+					.filter(bd -> bd.getFactoryBeanName() != null)//
+					.filter(bd -> isBeanMethodAnnotated(beanFactory, bd, annotationType))//
+					.forEach(bd -> System.out.println("@Bean method " + bd.getFactoryMethodName()
+							+ " is annotated with @" + annotationType.getSimpleName() + "."));
+		}
+
+		private boolean isBeanMethodAnnotated(ConfigurableListableBeanFactory beanFactory,
+				BeanDefinition beanDefinition, Class<? extends Annotation> annotationType) {
+
+			BeanDefinition factoryBeanDefinition = beanFactory.getBeanDefinition(beanDefinition.getFactoryBeanName());
+
+			if (factoryBeanDefinition instanceof AbstractBeanDefinition) {
+				AbstractBeanDefinition abd = (AbstractBeanDefinition) factoryBeanDefinition;
+				if (abd.hasBeanClass()) {
+					Class<?> factoryClass = ClassUtils.getUserClass(abd.getBeanClass());
+					String factoryMethodName = beanDefinition.getFactoryMethodName();
+					Method factoryMethod = ReflectionUtils.findMethod(factoryClass, factoryMethodName);
+					return AnnotatedElementUtils.isAnnotated(factoryMethod, Bean.class)
+							&& AnnotatedElementUtils.isAnnotated(factoryMethod, annotationType);
+				}
+			}
+
+			return false;
+		}
+
+	}
+
+	@Target(ElementType.METHOD)
+	@Retention(RetentionPolicy.RUNTIME)
+	@interface MyAnnotation {
+	}
+
+}