Java中使用观察者模式实现自定义事件
MyEventTest java:
package wintys event;
import javax swing event EventListenerList;
import java util Date;
import java text DateFormat;
import java text SimpleDateFormat;
/**
* Java的事件机制/自定义事件
运行结果:
do something interesting in source here
listener detects [event]:wintys event MyEvent[source=wintys event MySource@
] [occur at]: : :
listener detects [event]:wintys event MyEvent[source=wintys event MySource@
] [occur at]: : :
* @version
* @author 天堂露珠 ()
* @see
*/
class MyEventTest{
public static void main(String[] args){
MySource source = new MySource();
MyListener myListener = new MyListener(){
public void doMyAction(MyEvent e){
System out println( listener detects + e);
}
};
source addMyListener(myListener);
source addMyListener(myListener);
source addMyListener(myListener);
source removeMyListener(myListener);
亏友source doSomething();
}
}
/**
* 自定义的事件
* @version
* @author 天堂露珠()
* @see
*/
class MyEvent extends java util EventObject{
private Date date;//记录事件发生的时间
public MyEvent(Object source Date date){
super(source);
this date = date;
}
public String toString(){
DateFormat df = new SimpleDateFormat( yyyy MM dd HH:mm:ss );
String dt = df format(date);
return [event]: + super toString() + [occur at]: + dt;
}
}
/**
* 自定义事件监听器接口
* @version
* @author 天堂露珠()
* @see
*/
interface MyListener extends java util EventListener{
void doMyAction(MyEvent e);
高高 }
/**
* 自定义事件源
* @version
* @author 天堂露珠()
* @see
*/
class MySource{
/**
* 保存注册的监听器戚空尺列表
* 子类可以使用它保存自己的事件监听器(非MyListener监听器)列表
*/
protected EventListenerList listenerList = new EventListenerList();
private MyEvent myEvent = null;//fireDoMyAction()使用此变量
/**
* 没有做任何事
*/
public MySource(){
}
/**
* 添加一个MyListener监听器
*/
public void addMyListener(MyListener listener){
listenerList add(MyListener class listener);
}
/**
* 移除一个已注册的MyListener监听器
* 如果监听器列表中已有相同的监听器listener listener
* 并且listener ==listener
* 那么只移除最近注册的一个监听器
*/
public void removeMyListener(MyListener listener){
listenerList remove(MyListener class listener);
}
/**
* @return 在此对象上监听的所有MyListener类型的监听器
*/
public MyListener[] getMyListeners(){
return (MyListener[])listenerList getListeners(MyListener class);
}
//Winty:Copy directly from javax swing event EventListenerList
/*Notify all listeners that have registered interest for
notification on this event type The event instance
is lazily created using the parameters passed into
the fire method
*/
protected void fireDoMyAction() {
// getListenerList() Guaranteed to return a non null array
Object[] listeners = listenerList getListenerList();
// Process the listeners last to first notifying
// those that are interested in this event
for (int i = listeners length ; i= ; i = ) {
if (listeners[i]==MyListener class) {
// Lazily create the event:
if (myEvent == null)
myEvent = new MyEvent(this new Date());
((MyListener)listeners[i+ ]) doMyAction(myEvent);
}
}
}
/**
* 做一些事件源应该做的有意义的事 然后通知监听器
* 这里只是一个示例方法
* 例如:MySource如果是一个按钮 则doSomething()就可以命名为click()
* 当用户点击按钮时调用click()方法
*/
public void doSomething() {
System out println( do something interesting here );
fireDoMyAction();//通知监听器
}
}
lishixinzhi/Article/program/Java/hx/201311/26237
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