Springソースのイベント駆動モデル
34734 ワード
Spring Conteetの初期化イベントの発布者22123;
//spring
//spring
public abstract class AbstractApplicationContext extends DefaultResourceLoader
implements ConfigurableApplicationContext, DisposableBean {
/** */
private ApplicationEventMulticaster applicationEventMulticaster;
/** */
private Set> applicationListeners = new LinkedHashSet>();
//====== ========／
public void refresh() throws BeansException, IllegalStateException {
//====== ========／
// Initialize event multicaster for this context.
initApplicationEventMulticaster();
// Initialize other special beans in specific context subclasses.
onRefresh();
// bean 。
registerListeners();
//====== ========／
}
//====== ========／
/**
* ApplicationEventMulticaster.
* ， SimpleApplicationEventMulticaster。
* @see org.springframework.context.event.SimpleApplicationEventMulticaster
*/
protected void initApplicationEventMulticaster() {
// bean
ConfigurableListableBeanFactory beanFactory = getBeanFactory();
// ApplicationEventMulticaster （ ）
if (beanFactory.containsLocalBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME)) {
this.applicationEventMulticaster =
beanFactory.getBean(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, ApplicationEventMulticaster.class);
if (logger.isDebugEnabled()) {
logger.debug("Using ApplicationEventMulticaster [" + this.applicationEventMulticaster + "]");
}
}
else {// ， ， ，
this.applicationEventMulticaster = new SimpleApplicationEventMulticaster(beanFactory);
beanFactory.registerSingleton(APPLICATION_EVENT_MULTICASTER_BEAN_NAME, this.applicationEventMulticaster);
if (logger.isDebugEnabled()) {
logger.debug("Unable to locate ApplicationEventMulticaster with name '" +
APPLICATION_EVENT_MULTICASTER_BEAN_NAME +
"': using default [" + this.applicationEventMulticaster + "]");
}
}
}
/**
* ApplicationListener bean
* Doesn't affect other listeners, which can be added without being beans.
*/
protected void registerListeners() {
// 。
for (ApplicationListener> listener : getApplicationListeners()) {
getApplicationEventMulticaster().addApplicationListener(listener);
}
/**
* FactoryBeans： bean ， bean ！
*/
// ApplicationListener
//includeNonSingletons false Bean，true
//allowEagerInit true ，false 。
String[] listenerBeanNames = getBeanNamesForType(ApplicationListener.class, true, false);
for (String lisName : listenerBeanNames) {
getApplicationEventMulticaster().addApplicationListenerBean(lisName);
}
}
//
public void publishEvent(ApplicationEvent event) {
Assert.notNull(event, "Event must not be null");
if (logger.isTraceEnabled()) {
logger.trace("Publishing event in " + getDisplayName() + ": " + event);
}
// applicationEventMulticaster ， multicastEvent(event)
getApplicationEventMulticaster().multicastEvent(event);
if (this.parent != null) {
this.parent.publishEvent(event);
}
}
}
// ， ,id “applicationEventMulticaster”
"applicationEventMulticaster" class="org.springframework.context.event.SimpleApplicationEventMulticaster">
"taskExecutor" ref="executor"/>
// ：spring
public class EventObject implements java.io.Serializable {
private static final long serialVersionUID = 5516075349620653480L;
/**
* 。
*/
protected transient Object source;
//
public EventObject(Object source) {
if (source == null)
throw new IllegalArgumentException("null source");
this.source = source;
}
public Object getSource() {
return source;
}
public String toString() {
return getClass().getName() + "[source=" + source + "]";
}
}
//
public abstract class ApplicationEvent extends EventObject {
/** use serialVersionUID from Spring 1.2 for interoperability */
private static final long serialVersionUID = 7099057708183571937L;
/** System time when the event happened */
private final long timestamp;
/**
* Create a new ApplicationEvent.
* @param source the component that published the event (never {@code null})
*/
public ApplicationEvent(Object source) {
super(source);
this.timestamp = System.currentTimeMillis();
}
/**
* Return the system time in milliseconds when the event happened.
*/
public final long getTimestamp() {
return this.timestamp;
}
}
// ：
public interface ApplicationEventMulticaster {
/**
* bean
* @param listener the listener to add
*/
void addApplicationListener(ApplicationListener listener);
/**
* beanName
* @param listenerBeanName the name of the listener bean to add
*/
void addApplicationListenerBean(String listenerBeanName);
/**
* bean
* @param listener the listener to remove
*/
void removeApplicationListener(ApplicationListener listener);
/**
* beanName
* @param listenerBeanName the name of the listener bean to add
*/
void removeApplicationListenerBean(String listenerBeanName);
/**
* Multicaster 。
*/
void removeAllListeners();
/**
* 。
* @param event the event to multicast
*/
void multicastEvent(ApplicationEvent event);
}
//
public interface Aware {
}
// BeanFactory
public interface BeanFactoryAware extends Aware {
void setBeanFactory(BeanFactory beanFactory) throws BeansException;
}
// bean
public interface BeanClassLoaderAware extends Aware {
void setBeanClassLoader(ClassLoader classLoader);
}
// ，
public abstract class AbstractApplicationEventMulticaster
implements ApplicationEventMulticaster, BeanClassLoaderAware, BeanFactoryAware {
// （ ： beanName）
private final ListenerRetriever defaultRetriever = new ListenerRetriever(false);
private final Map retrieverCache =
new ConcurrentHashMap(64);
// : null ， eventType sourceType ClassLoader 。
private ClassLoader beanClassLoader;
//bean ： defaultRetriever listenerBeanName bean
private BeanFactory beanFactory;
// bean
public void addApplicationListener(ApplicationListener listener) {
synchronized (this.defaultRetriever) {
this.defaultRetriever.applicationListeners.add(listener);
this.retrieverCache.clear();
}
}
// beanName
public void addApplicationListenerBean(String listenerBeanName) {
synchronized (this.defaultRetriever) {
this.defaultRetriever.applicationListenerBeans.add(listenerBeanName);
this.retrieverCache.clear();
}
}
// bean
public void removeApplicationListener(ApplicationListener listener) {
synchronized (this.defaultRetriever) {
this.defaultRetriever.applicationListeners.remove(listener);
this.retrieverCache.clear();
}
}
// beanName
public void removeApplicationListenerBean(String listenerBeanName) {
synchronized (this.defaultRetriever) {
this.defaultRetriever.applicationListenerBeans.remove(listenerBeanName);
this.retrieverCache.clear();
}
}
//
public void removeAllListeners() {
synchronized (this.defaultRetriever) {
this.defaultRetriever.applicationListeners.clear();
this.defaultRetriever.applicationListenerBeans.clear();
this.retrieverCache.clear();
}
}
public void setBeanClassLoader(ClassLoader classLoader) {
this.beanClassLoader = classLoader;
}
public void setBeanFactory(BeanFactory beanFactory) {
this.beanFactory = beanFactory;
if (this.beanClassLoader == null && beanFactory instanceof ConfigurableBeanFactory) {
this.beanClassLoader = ((ConfigurableBeanFactory) beanFactory).getBeanClassLoader();
}
}
private BeanFactory getBeanFactory() {
if (this.beanFactory == null) {
throw new IllegalStateException("ApplicationEventMulticaster cannot retrieve listener beans " +
"because it is not associated with a BeanFactory");
}
return this.beanFactory;
}
//
protected Collection getApplicationListeners() {
synchronized (this.defaultRetriever) {
return this.defaultRetriever.getApplicationListeners();
}
}
// ApplicationListeners 。 。
protected Collection getApplicationListeners(ApplicationEvent event) {
Class extends ApplicationEvent> eventType = event.getClass();
Object source = event.getSource();
Class> sourceType = (source != null ? source.getClass() : null);
ListenerCacheKey cacheKey = new ListenerCacheKey(eventType, sourceType);
//
ListenerRetriever retriever = this.retrieverCache.get(cacheKey);
if (retriever != null) {
return retriever.getApplicationListeners();
}
//
if (this.beanClassLoader == null ||
// ， ， ClassLoader 。
(ClassUtils.isCacheSafe(eventType, this.beanClassLoader) &&
(sourceType == null || ClassUtils.isCacheSafe(sourceType, this.beanClassLoader)))) {
// Fully synchronized building and caching of a ListenerRetriever
synchronized (this.defaultRetriever) {
retriever = this.retrieverCache.get(cacheKey);
if (retriever != null) {
return retriever.getApplicationListeners();
}
retriever = new ListenerRetriever(true);
Collection listeners = retrieveApplicationListeners(eventType, sourceType, retriever);
//
this.retrieverCache.put(cacheKey, retriever);
return listeners;
}
}
else {
// ListenerRetriever - > synchronization
return retrieveApplicationListeners(eventType, sourceType, null);
}
}
/**
* 。
* @param eventType the application 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 retrieveApplicationListeners(
Class extends ApplicationEvent> eventType, Class> sourceType, ListenerRetriever retriever) {
LinkedList allListeners = new LinkedList();
Set listeners;
Set listenerBeans;
synchronized (this.defaultRetriever) {
listeners = new LinkedHashSet(this.defaultRetriever.applicationListeners);
listenerBeans = new LinkedHashSet(this.defaultRetriever.applicationListenerBeans);
}
for (ApplicationListener listener : listeners) {
if (supportsEvent(listener, eventType, sourceType)) {
if (retriever != null) {
retriever.applicationListeners.add(listener);
}
allListeners.add(listener);
}
}
if (!listenerBeans.isEmpty()) {
BeanFactory beanFactory = getBeanFactory();
for (String listenerBeanName : listenerBeans) {
ApplicationListener listener = beanFactory.getBean(listenerBeanName, ApplicationListener.class);
if (!allListeners.contains(listener) && supportsEvent(listener, eventType, sourceType)) {
if (retriever != null) {
retriever.applicationListenerBeans.add(listenerBeanName);
}
allListeners.add(listener);
}
}
}
OrderComparator.sort(allListeners);
return allListeners;
}
// 。
protected boolean supportsEvent(
ApplicationListener listener, Class extends ApplicationEvent> eventType, Class> sourceType) {
SmartApplicationListener smartListener = (listener instanceof SmartApplicationListener ?
(SmartApplicationListener) listener : new GenericApplicationListenerAdapter(listener));
return (smartListener.supportsEventType(eventType) && smartListener.supportsSourceType(sourceType));
}
/**
* Cache key for ListenerRetrievers, based on event type and source type.
* ListenerRetrievers 。
*/
private static class ListenerCacheKey {
//
private final Class> eventType;
//source
private final Class> sourceType;
public ListenerCacheKey(Class> eventType, Class> sourceType) {
this.eventType = eventType;
this.sourceType = sourceType;
}
@Override
public boolean equals(Object other) {
if (this == other) {
return true;
}
ListenerCacheKey otherKey = (ListenerCacheKey) other;
return ObjectUtils.nullSafeEquals(this.eventType, otherKey.eventType) &&
ObjectUtils.nullSafeEquals(this.sourceType, otherKey.sourceType);
}
@Override
public int hashCode() {
return ObjectUtils.nullSafeHashCode(this.eventType) * 29 + ObjectUtils.nullSafeHashCode(this.sourceType);
}
}
//Helper ， 。
// 。
private class ListenerRetriever {
// bean
public final Set applicationListeners;
// bean
public final Set applicationListenerBeans;
//
private final boolean preFiltered;
public ListenerRetriever(boolean preFiltered) {
this.applicationListeners = new LinkedHashSet();
this.applicationListenerBeans = new LinkedHashSet();
this.preFiltered = preFiltered;
}
//
public Collection getApplicationListeners() {
LinkedList allListeners = new LinkedList();
for (ApplicationListener listener : this.applicationListeners) {
allListeners.add(listener);
}
if (!this.applicationListenerBeans.isEmpty()) {
// bean
BeanFactory beanFactory = getBeanFactory();
for (String listenerBeanName : this.applicationListenerBeans) {
// bean （ ）
ApplicationListener listener = beanFactory.getBean(listenerBeanName, ApplicationListener.class);
// （ ） allListeners ； ，
if (this.preFiltered || !allListeners.contains(listener)) {
allListeners.add(listener);
}
}
}
//
OrderComparator.sort(allListeners);
return allListeners;
}
}
}
//spring
public class SimpleApplicationEventMulticaster extends AbstractApplicationEventMulticaster {
//
private Executor taskExecutor;
//
public SimpleApplicationEventMulticaster() {
}
/**
* Create a new SimpleApplicationEventMulticaster for the given BeanFactory.
*/
public SimpleApplicationEventMulticaster(BeanFactory beanFactory) {
setBeanFactory(beanFactory);
}
// Executor 。
public void setTaskExecutor(Executor taskExecutor) {
this.taskExecutor = taskExecutor;
}
protected Executor getTaskExecutor() {
return this.taskExecutor;
}
@SuppressWarnings("unchecked")
public void multicastEvent(final ApplicationEvent event) {
for (final ApplicationListener listener : getApplicationListeners(event)) {
Executor executor = getTaskExecutor();
// （ ， Executor ）
if (executor != null) {
executor.execute(new Runnable() {
public void run() {
listener.onApplicationEvent(event);
}
});
}
else {// （ ： ）
listener.onApplicationEvent(event);
}
}
}
}
public interface EventListener {
}
public interface ApplicationListener<E extends ApplicationEvent> extends EventListener {
/**
*
* @param event the event to respond to
*/
void onApplicationEvent(E event);
}