一,jdk 事件对象基类
package java.util;
import java.io.Serializable;
public class EventObject
implements Serializable
{
protected transient Object source;
public Object getSource()
{
return this.source;
}
public EventObject(Object paramObject)
{
if (paramObject == null)
throw new IllegalArgumentException("null source");
this.source = paramObject;
}
public String toString()
{
return getClass().getName() + "[source=" + this.source + "]";
}
}
2。spring事件基类
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</code>)
*/
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;
}
}
3，ApplicationContextEvent基类
public abstract class ApplicationContextEvent extends ApplicationEvent {
/**
* Create a new ContextStartedEvent.
* @param source the <code>ApplicationContext</code> that the event is raised for
* (must not be <code>null</code>)
*/
public ApplicationContextEvent(ApplicationContext source) {
super(source);
}
/**
* Get the <code>ApplicationContext</code> that the event was raised for.
*/
public final ApplicationContext getApplicationContext() {
return (ApplicationContext) getSource();
}
}
4。容器关闭事件
public class ContextClosedEvent extends ApplicationContextEvent {
/**
* Creates a new ContextClosedEvent.
* @param source the <code>ApplicationContext</code> that has been closed
* (must not be <code>null</code>)
*/
public ContextClosedEvent(ApplicationContext source) {
super(source);
}
}
5，AbstractApplicationContext中fireclose事件
public void publishEvent(ApplicationEvent event) {
Assert.notNull(event, "Event must not be null");
if (logger.isTraceEnabled()) {
logger.trace("Publishing event in " + getDisplayName() + ": " + event);
}
getApplicationEventMulticaster().multicastEvent(event);
if (this.parent != null) {
this.parent.publishEvent(event);
}
}
6，事件处理监听器控制器(SimpleApplicationEventMulticaster)
@SuppressWarnings("unchecked")
public void multicastEvent(final ApplicationEvent event) {
for (final ApplicationListener listener : getApplicationListeners(event)) {
Executor executor = getTaskExecutor();
if (executor != null) {
executor.execute(new Runnable() {
@SuppressWarnings("unchecked")
public void run() {
listener.onApplicationEvent(event);
}
});
}
else {
listener.onApplicationEvent(event);
}
}
}
7。AbstractApplicationEventMulticaster获取注冊close事件的监听器
protected Collection<applicationlistener> getApplicationListeners(ApplicationEvent event) {
Class<? extends ApplicationEvent> eventType = event.getClass();
Class sourceType = event.getSource().getClass();
ListenerCacheKey cacheKey = new ListenerCacheKey(eventType, sourceType);
ListenerRetriever retriever = this.retrieverCache.get(cacheKey);
if (retriever != null) {
return retriever.getApplicationListeners();
}
else {
retriever = new ListenerRetriever(true);
LinkedList<applicationlistener> allListeners = new LinkedList<applicationlistener>();
synchronized (this.defaultRetriever) {
for (ApplicationListener listener : this.defaultRetriever.applicationListeners) {
if (supportsEvent(listener, eventType, sourceType)) {
retriever.applicationListeners.add(listener);
allListeners.add(listener);
}
}
if (!this.defaultRetriever.applicationListenerBeans.isEmpty()) {
BeanFactory beanFactory = getBeanFactory();
for (String listenerBeanName : this.defaultRetriever.applicationListenerBeans) {
ApplicationListener listener = beanFactory.getBean(listenerBeanName, ApplicationListener.class);
if (!allListeners.contains(listener) && supportsEvent(listener, eventType, sourceType)) {
retriever.applicationListenerBeans.add(listenerBeanName);
allListeners.add(listener);
}
}
}
OrderComparator.sort(allListeners);
this.retrieverCache.put(cacheKey, retriever);
}
return allListeners;
}
}
二,
1，监听器基类
public interface EventListener
{
}
2，spring监听器基类
public interface ApplicationListener<e extends="" applicationevent=""> extends EventListener {
/**
* Handle an application event.
* @param event the event to respond to
*/
void onApplicationEvent(E event);
}
3。AbstractApplicationContext加入监听
public void addApplicationListener(ApplicationListener<?> listener) {
if (this.applicationEventMulticaster != null) {
this.applicationEventMulticaster.addApplicationListener(listener);
}
else {
this.applicationListeners.add(listener);
}
}
4，加入listenner到AbstractApplicationEventMulticaster
public void addApplicationListener(ApplicationListener listener) {
synchronized (this.defaultRetriever) {
this.defaultRetriever.applicationListeners.add(listener);
this.retrieverCache.clear();
}
}
5，监听处理类注冊入口AbstractApplicationContext
public Object postProcessAfterInitialization(Object bean, String beanName) {
if (bean instanceof ApplicationListener) {
// potentially not detected as a listener by getBeanNamesForType retrieval
Boolean flag = this.singletonNames.get(beanName);
if (Boolean.TRUE.equals(flag)) {
// singleton bean (top-level or inner): register on the fly
addApplicationListener((ApplicationListener<?>) bean);
}
else if (flag == null) {
if (logger.isWarnEnabled() && !containsBean(beanName)) {
// inner bean with other scope - can't reliably process events
logger.warn("Inner bean '" + beanName + "' implements ApplicationListener interface " +
"but is not reachable for event multicasting by its containing ApplicationContext " +
"because it does not have singleton scope. Only top-level listener beans are allowed " +
"to be of non-singleton scope.");
}
this.singletonNames.put(beanName, Boolean.FALSE);
}
}
return bean;
}
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