Java设计模式之监听器模式实例详解

public class Child {
  private String name;
  private RemindListener remindListener;
  public Child(String name){
    this.name = name;
  }
  public void eat() {
    if(null!=remindListener){
      remindListener.remind(new RemindWashingHandsEvent(this));
    }
    System.out.println("Child eat...");
  }
  public void addListener(RemindListener listener){
    remindListener = listener;
  }
}

public class RemindWashingHandsEvent {
  private Child child;
  public RemindWashingHandsEvent(Child child){
    this.child = child;
  }
}

public class RemindListener {
  public void remind(RemindWashingHandsEvent remindWashingHandsEvent){
    System.out.println("listen to mom, washing hands before eating...");
  }
}

public class Kid{
  private String name;
  private List<Listener> liteners;
  public Kid(String name) {
    this.name = name;
    this.liteners = Lists.newArrayList();
  }
  public void eat(){
    for(Listener listener:liteners){
      if(listener instanceof WashingHandsListener){
        WashingHandsListener washingHandsListener = (WashingHandsListener) listener;
        washingHandsListener.fireAfterEventInvoked(new WashingHandsEvent(this,"洗手"));
      }
    }
    System.out.println("吃饭...");
  }
  public void addListener(Listener listener){
    liteners.add(listener);
  }
}
public class Event extends EventObject {
  /**
   * Constructs a prototypical Event.
   *
   * @param source The object on which the Event initially occurred.
   * @throws IllegalArgumentException if source is null.
   */
  public Event(Object source) {
    super(source);
  }
}
public class WashingHandsEvent extends Event{
  private String eventName;
  /**
   * Constructs a prototypical Event.
   *
   * @param source The object on which the Event initially occurred.
   * @throws IllegalArgumentException if source is null.
   */
  public WashingHandsEvent(Object source,String eventName) {
    super(source);
    this.eventName = eventName;
  }
  public String getEventName() {
    return eventName;
  }
  public void setEventName(String eventName) {
    this.eventName = eventName;
  }
}
public interface Listener extends java.util.EventListener{
  public void fireAfterEventInvoked(Event event);
}
public class WashingHandsListener implements Listener{
  @Override
  public void fireAfterEventInvoked(Event event) {
    WashingHandsEvent washingHandsEvent = (WashingHandsEvent) event;
    System.out.println("饭前准备"+ washingHandsEvent.getEventName());
  }
}
public class Test {
  public static void main(String[] args) {
    Kid xiaoming = new Kid("xiaoming");
    xiaoming.addListener(new WashingHandsListener());
    xiaoming.eat();
  }
}