Java事件处理机制（自定义事件）实例详解

/**
* 定义事件对象，必须继承EventObject
*/
public class DoorEvent extends EventObject {

 private static final long serialVersionUID = 6496098798146410884L;

 private String doorState = "";// 表示门的状态，有“开”和“关”两种

 public DoorEvent(Object source, String doorState) {
  super(source);
  this.doorState = doorState;
 }

 public void setDoorState(String doorState) {
  this.doorState = doorState;
 }

 public String getDoorState() {
  return this.doorState;
 }

}

/**
* 定义监听接口，负责监听DoorEvent事件
*/

public interface DoorListener extends EventListener {
  public void doorEvent(DoorEvent event);
}

/**
* 该类为 门1监听接口的实现，做具体的开门，关门动作
*/


public class DoorListener1 implements DoorListener {
 @Override
 public void doorEvent(DoorEvent event) {
  // TODO Auto-generated method stub
  if (event.getDoorState() != null && event.getDoorState().equals("open")) {
   System.out.println("门1打开");
  } else {
   System.out.println("门1关闭");
  }
 }

}

/**

* 该类为 门2监听接口的实现，做具体的开门，关门，以及开灯，关灯动作
*/


public class DoorListener2 implements DoorListener {

 @Override
 public void doorEvent(DoorEvent event) {
  // TODO Auto-generated method stub
  if (event.getDoorState() != null && event.getDoorState().equals("open")) {
   System.out.println("门2打开，同时打开走廊的灯");
  } else {
   System.out.println("门2关闭，同时关闭走廊的灯");
  }
 }

}

/**
* 事件源对象，在这里你可以把它想象成一个控制开门关门的遥控器，
* (如果是在swing中，就类似一个button)
*/


public class DoorManager {
 private Collection listeners;

 /**
  * 添加事件
  * 
  * @param listener
  *   DoorListener
  */
 public void addDoorListener(DoorListener listener) {
  if (listeners == null) {
   listeners = new HashSet();
  }
  listeners.add(listener);
 }

 /**
  * 移除事件
  * 
  * @param listener
  *   DoorListener
  */
 public void removeDoorListener(DoorListener listener) {
  if (listeners == null)
   return;
  listeners.remove(listener);
 }

 /**
  * 触发开门事件
  */
 protected void fireWorkspaceOpened() {
  if (listeners == null)
   return;
  DoorEvent event = new DoorEvent(this, "open");
  notifyListeners(event);
 }

 /**
  * 触发关门事件
  */
 protected void fireWorkspaceClosed() {
  if (listeners == null)
   return;
  DoorEvent event = new DoorEvent(this, "close");
  notifyListeners(event);
 }

 /**
  * 通知所有的DoorListener
  */
 private void notifyListeners(DoorEvent event) {
  Iterator iter = listeners.iterator();
  while (iter.hasNext()) {
   DoorListener listener = (DoorListener) iter.next();
   listener.doorEvent(event);
  }
 }
}

/**
* 主程序，就想象成要开门的哪个人
*/


public class DoorMain {
 public static void main(String[] args) {
  DoorManager manager = new DoorManager();
  manager.addDoorListener(new DoorListener1());// 给门1增加监听器
  manager.addDoorListener(new DoorListener2());// 给门2增加监听器
  // 开门
  manager.fireWorkspaceOpened();
  System.out.println("我已经进来了");
  // 关门
  manager.fireWorkspaceClosed();
 }
}