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Avoid potential deadlocks between event multicaster and singleton registry through shared lock 

Issue: SPR-12739
This commit is contained in:
Juergen Hoeller 2015-02-26 18:35:06 +01:00
parent 287045ef74
commit 81102deedf
3 changed files with 67 additions and 56 deletions
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9
spring-beans/src/main/java/org/springframework/beans/factory/config/SingletonBeanRegistry.java
View File

@ -1,5 +1,5 @@
/*
* Copyright 2002-2012 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.
@ -122,4 +122,11 @@ public interface SingletonBeanRegistry {
*/
int getSingletonCount();
/**
* Return the singleton mutex used by this registry (for external collaborators).
* @return the mutex object (never {@code null})
* @since 4.2
*/
Object getSingletonMutex();
}

6
spring-beans/src/main/java/org/springframework/beans/factory/support/DefaultSingletonBeanRegistry.java
View File

@ -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.
@ -607,13 +607,13 @@ public class DefaultSingletonBeanRegistry extends SimpleAliasRegistry implements
}
/**
* Expose the singleton mutex to subclasses.
* Exposes the singleton mutex to subclasses and external collaborators.
* <p>Subclasses should synchronize on the given Object if they perform
* any sort of extended singleton creation phase. In particular, subclasses
* should <i>not</i> have their own mutexes involved in singleton creation,
* to avoid the potential for deadlocks in lazy-init situations.
*/
protected final Object getSingletonMutex() {
public final Object getSingletonMutex() {
return this.singletonObjects;
}

108
spring-context/src/main/java/org/springframework/context/event/AbstractApplicationEventMulticaster.java
View File

@ -67,47 +67,8 @@ public abstract class AbstractApplicationEventMulticaster
private BeanFactory beanFactory;
private Object retrievalMutex = this.defaultRetriever;
@Override
public void addApplicationListener(ApplicationListener<?> listener) {
synchronized (this.defaultRetriever) {
this.defaultRetriever.applicationListeners.add(listener);
this.retrieverCache.clear();
}
}
@Override
public void addApplicationListenerBean(String listenerBeanName) {
synchronized (this.defaultRetriever) {
this.defaultRetriever.applicationListenerBeans.add(listenerBeanName);
this.retrieverCache.clear();
}
}
@Override
public void removeApplicationListener(ApplicationListener<?> listener) {
synchronized (this.defaultRetriever) {
this.defaultRetriever.applicationListeners.remove(listener);
this.retrieverCache.clear();
}
}
@Override
public void removeApplicationListenerBean(String listenerBeanName) {
synchronized (this.defaultRetriever) {
this.defaultRetriever.applicationListenerBeans.remove(listenerBeanName);
this.retrieverCache.clear();
}
}
@Override
public void removeAllListeners() {
synchronized (this.defaultRetriever) {
this.defaultRetriever.applicationListeners.clear();
this.defaultRetriever.applicationListenerBeans.clear();
this.retrieverCache.clear();
}
}
@Override
public void setBeanClassLoader(ClassLoader classLoader) {
@ -117,8 +78,12 @@ public abstract class AbstractApplicationEventMulticaster
@Override
public void setBeanFactory(BeanFactory beanFactory) {
this.beanFactory = beanFactory;
if (this.beanClassLoader == null && beanFactory instanceof ConfigurableBeanFactory) {
this.beanClassLoader = ((ConfigurableBeanFactory) beanFactory).getBeanClassLoader();
if (beanFactory instanceof ConfigurableBeanFactory) {
ConfigurableBeanFactory cbf = (ConfigurableBeanFactory) beanFactory;
if (this.beanClassLoader == null) {
this.beanClassLoader = cbf.getBeanClassLoader();
}
this.retrievalMutex = cbf.getSingletonMutex();
}
}
@ -131,13 +96,55 @@ public abstract class AbstractApplicationEventMulticaster
}
@Override
public void addApplicationListener(ApplicationListener<?> listener) {
synchronized (this.retrievalMutex) {
this.defaultRetriever.applicationListeners.add(listener);
this.retrieverCache.clear();
}
}
@Override
public void addApplicationListenerBean(String listenerBeanName) {
synchronized (this.retrievalMutex) {
this.defaultRetriever.applicationListenerBeans.add(listenerBeanName);
this.retrieverCache.clear();
}
}
@Override
public void removeApplicationListener(ApplicationListener<?> listener) {
synchronized (this.retrievalMutex) {
this.defaultRetriever.applicationListeners.remove(listener);
this.retrieverCache.clear();
}
}
@Override
public void removeApplicationListenerBean(String listenerBeanName) {
synchronized (this.retrievalMutex) {
this.defaultRetriever.applicationListenerBeans.remove(listenerBeanName);
this.retrieverCache.clear();
}
}
@Override
public void removeAllListeners() {
synchronized (this.retrievalMutex) {
this.defaultRetriever.applicationListeners.clear();
this.defaultRetriever.applicationListenerBeans.clear();
this.retrieverCache.clear();
}
}
/**
* Return a Collection containing all ApplicationListeners.
* @return a Collection of ApplicationListeners
* @see org.springframework.context.ApplicationListener
*/
protected Collection<ApplicationListener<?>> getApplicationListeners() {
synchronized (this.defaultRetriever) {
synchronized (this.retrievalMutex) {
return this.defaultRetriever.getApplicationListeners();
}
}
@ -168,39 +175,38 @@ public abstract class AbstractApplicationEventMulticaster
(ClassUtils.isCacheSafe(event.getClass(), this.beanClassLoader) &&
(sourceType == null || ClassUtils.isCacheSafe(sourceType, this.beanClassLoader)))) {
// Fully synchronized building and caching of a ListenerRetriever
synchronized (this.defaultRetriever) {
synchronized (this.retrievalMutex) {
retriever = this.retrieverCache.get(cacheKey);
if (retriever != null) {
return retriever.getApplicationListeners();
}
retriever = new ListenerRetriever(true);
Collection<ApplicationListener<?>> listeners =
retrieveApplicationListeners(event, eventType, sourceType, retriever);
retrieveApplicationListeners(eventType, sourceType, retriever);
this.retrieverCache.put(cacheKey, retriever);
return listeners;
}
}
else {
// No ListenerRetriever caching -> no synchronization necessary
return retrieveApplicationListeners(event, eventType, sourceType, null);
return retrieveApplicationListeners(eventType, sourceType, null);
}
}
/**
* Actually retrieve the application listeners for the given event and source type.
* @param event the application event
* @param eventType the event type
* @param sourceType the event source type
* @param retriever the ListenerRetriever, if supposed to populate one (for caching purposes)
* @return the pre-filtered list of application listeners for the given event and source type
*/
private Collection<ApplicationListener<?>> retrieveApplicationListeners(
ApplicationEvent event, ResolvableType eventType, Class<?> sourceType, ListenerRetriever retriever) {
ResolvableType eventType, Class<?> sourceType, ListenerRetriever retriever) {
LinkedList<ApplicationListener<?>> allListeners = new LinkedList<ApplicationListener<?>>();
Set<ApplicationListener<?>> listeners;
Set<String> listenerBeans;
synchronized (this.defaultRetriever) {
synchronized (this.retrievalMutex) {
listeners = new LinkedHashSet<ApplicationListener<?>>(this.defaultRetriever.applicationListeners);
listenerBeans = new LinkedHashSet<String>(this.defaultRetriever.applicationListenerBeans);
}
@ -270,9 +276,7 @@ public abstract class AbstractApplicationEventMulticaster
* @return whether the given listener should be included in the candidates
* for the given event type
*/
protected boolean supportsEvent(ApplicationListener<?> listener,
ResolvableType eventType, Class<?> sourceType) {
protected boolean supportsEvent(ApplicationListener<?> listener, ResolvableType eventType, Class<?> sourceType) {
GenericApplicationListener smartListener = (listener instanceof GenericApplicationListener ?
(GenericApplicationListener) listener : new GenericApplicationListenerAdapter(listener));
return (smartListener.supportsEventType(eventType) && smartListener.supportsSourceType(sourceType));