AbstractApplicationContext's ApplicationListenerDetector removes listeners from ApplicationEventMulticaster on individual destruction

Issue: SPR-7856

Author: jhoeller

spring-context/src/main/java/org/springframework/context/support/AbstractApplicationContext.java

@@ -341,7 +341,7 @@ public void publishEvent(ApplicationEvent event) {
 	 * @return the internal ApplicationEventMulticaster (never {@code null})
 	 * @throws IllegalStateException if the context has not been initialized yet
 	 */
-	private ApplicationEventMulticaster getApplicationEventMulticaster() throws IllegalStateException {
+	ApplicationEventMulticaster getApplicationEventMulticaster() throws IllegalStateException {
 		if (this.applicationEventMulticaster == null) {
 			throw new IllegalStateException("ApplicationEventMulticaster not initialized - " +
 					"call 'refresh' before multicasting events via the context: " + this);
@@ -354,7 +354,7 @@ private ApplicationEventMulticaster getApplicationEventMulticaster() throws Ille
 	 * @return the internal LifecycleProcessor (never {@code null})
 	 * @throws IllegalStateException if the context has not been initialized yet
 	 */
-	private LifecycleProcessor getLifecycleProcessor() {
+	LifecycleProcessor getLifecycleProcessor() {
 		if (this.lifecycleProcessor == null) {
 			throw new IllegalStateException("LifecycleProcessor not initialized - " +
 					"call 'refresh' before invoking lifecycle methods via the context: " + this);

spring-context/src/main/java/org/springframework/context/support/PostProcessorRegistrationDelegate.java

@@ -31,12 +31,12 @@
 import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
 import org.springframework.beans.factory.config.BeanPostProcessor;
 import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
+import org.springframework.beans.factory.config.DestructionAwareBeanPostProcessor;
 import org.springframework.beans.factory.support.BeanDefinitionRegistry;
 import org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor;
 import org.springframework.beans.factory.support.MergedBeanDefinitionPostProcessor;
 import org.springframework.beans.factory.support.RootBeanDefinition;
 import org.springframework.context.ApplicationListener;
-import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.core.OrderComparator;
 import org.springframework.core.Ordered;
 import org.springframework.core.PriorityOrdered;
@@ -177,7 +177,7 @@ else if (beanFactory.isTypeMatch(ppName, Ordered.class)) {
 	}
 
 	public static void registerBeanPostProcessors(
-			ConfigurableListableBeanFactory beanFactory, ConfigurableApplicationContext applicationContext) {
+			ConfigurableListableBeanFactory beanFactory, AbstractApplicationContext applicationContext) {
 
 		String[] postProcessorNames = beanFactory.getBeanNamesForType(BeanPostProcessor.class, true, false);
 
@@ -319,15 +319,15 @@ public Object postProcessAfterInitialization(Object bean, String beanName) {
 	 * BeanPostProcessor that detects beans which implement the ApplicationListener interface.
 	 * This catches beans that can't reliably be detected by getBeanNamesForType.
 	 */
-	private static class ApplicationListenerDetector implements MergedBeanDefinitionPostProcessor {
+	private static class ApplicationListenerDetector implements MergedBeanDefinitionPostProcessor, DestructionAwareBeanPostProcessor {
 
 		private static final Log logger = LogFactory.getLog(ApplicationListenerDetector.class);
 
-		private final ConfigurableApplicationContext applicationContext;
+		private final AbstractApplicationContext applicationContext;
 
 		private final Map<String, Boolean> singletonNames = new ConcurrentHashMap<String, Boolean>(64);
 
-		public ApplicationListenerDetector(ConfigurableApplicationContext applicationContext) {
+		public ApplicationListenerDetector(AbstractApplicationContext applicationContext) {
 			this.applicationContext = applicationContext;
 		}
 
@@ -365,6 +365,14 @@ else if (flag == null) {
 			}
 			return bean;
 		}
+
+		@Override
+		public void postProcessBeforeDestruction(Object bean, String beanName) {
+			if (bean instanceof ApplicationListener) {
+				this.applicationContext.getApplicationEventMulticaster().removeApplicationListener((ApplicationListener) bean);
+				this.applicationContext.getApplicationEventMulticaster().removeApplicationListenerBean(beanName);
+			}
+		}
 	}
 
 }

spring-context/src/test/java/org/springframework/context/event/ApplicationContextEventTests.java

@@ -21,6 +21,7 @@
 
 import org.aopalliance.intercept.MethodInvocation;
 import org.junit.Test;
+
 import org.springframework.aop.framework.ProxyFactory;
 import org.springframework.beans.factory.config.RuntimeBeanReference;
 import org.springframework.beans.factory.support.RootBeanDefinition;
@@ -29,6 +30,7 @@
 import org.springframework.context.ApplicationListener;
 import org.springframework.context.BeanThatBroadcasts;
 import org.springframework.context.BeanThatListens;
+import org.springframework.context.support.AbstractApplicationContext;
 import org.springframework.context.support.StaticApplicationContext;
 import org.springframework.core.Ordered;
 import org.springframework.tests.sample.beans.TestBean;
@@ -134,6 +136,34 @@ public void listenersInApplicationContext() {
 		assertTrue(listener1.seenEvents.contains(event2));
 		assertTrue(listener1.seenEvents.contains(event3));
 		assertTrue(listener1.seenEvents.contains(event4));
+
+		context.close();
+	}
+
+	@Test
+	public void listenersInApplicationContextWithNestedChild() {
+		StaticApplicationContext context = new StaticApplicationContext();
+		RootBeanDefinition nestedChild = new RootBeanDefinition(StaticApplicationContext.class);
+		nestedChild.getPropertyValues().add("parent", context);
+		nestedChild.setInitMethodName("refresh");
+		context.registerBeanDefinition("nestedChild", nestedChild);
+		RootBeanDefinition listener1Def = new RootBeanDefinition(MyOrderedListener1.class);
+		listener1Def.setDependsOn(new String[] {"nestedChild"});
+		context.registerBeanDefinition("listener1", listener1Def);
+		context.refresh();
+
+		MyOrderedListener1 listener1 = context.getBean("listener1", MyOrderedListener1.class);
+		MyEvent event1 = new MyEvent(context);
+		context.publishEvent(event1);
+		assertTrue(listener1.seenEvents.contains(event1));
+
+		SimpleApplicationEventMulticaster multicaster = context.getBean(
+				AbstractApplicationContext.APPLICATION_EVENT_MULTICASTER_BEAN_NAME,
+				SimpleApplicationEventMulticaster.class);
+		assertFalse(multicaster.getApplicationListeners().isEmpty());
+
+		context.close();
+		assertTrue(multicaster.getApplicationListeners().isEmpty());
 	}
 
 	@Test
@@ -157,6 +187,8 @@ public void nonSingletonListenerInApplicationContext() {
 		assertTrue(MyNonSingletonListener.seenEvents.contains(event3));
 		assertTrue(MyNonSingletonListener.seenEvents.contains(event4));
 		MyNonSingletonListener.seenEvents.clear();
+
+		context.close();
 	}
 
 	@Test
@@ -171,6 +203,8 @@ public void listenerAndBroadcasterWithCircularReference() {
 		BeanThatBroadcasts broadcaster = context.getBean("broadcaster", BeanThatBroadcasts.class);
 		context.publishEvent(new MyEvent(context));
 		assertEquals("The event was not received by the listener", 2, broadcaster.receivedCount);
+
+		context.close();
 	}
 
 	@Test
@@ -180,10 +214,13 @@ public void innerBeanAsListener() {
 		listenerDef.getPropertyValues().add("friends", new RootBeanDefinition(BeanThatListens.class));
 		context.registerBeanDefinition("listener", listenerDef);
 		context.refresh();
+
 		context.publishEvent(new MyEvent(this));
 		context.publishEvent(new MyEvent(this));
 		TestBean listener = context.getBean(TestBean.class);
 		assertEquals(3, ((BeanThatListens) listener.getFriends().iterator().next()).getEventCount());
+
+		context.close();
 	}