观察者模式简单样例

深藏阁楼爱情的钟 2022-05-09 10:36 168阅读 0赞

测试公交车的打卡机样例：

CardMachine

import java.util.ArrayList;
    import java.util.Date;
    import java.util.List;
    
    public class CardMachine {
    	private List<EventPunchCardListener> listener = new ArrayList<EventPunchCardListener>();
    
    	 // 添加监听接口
    	public void addPunchListener(EventPunchCardListener clickOnListener) {
    		this.listener.add(clickOnListener);
    	}
    	
    	/**
    	  * 打卡 ing
    	  */
    	public void punchCard() {
    		for (EventPunchCardListener punch : listener) {
    			EventPunchCard eventPunch = new EventPunchCard(new Date(), this);
    			punch.performPunch(eventPunch);
    		}
    	}
    	
    	 /**
    	  * 测试打卡机器运转
    	  * 
    	  * @param args
    	  */
    	public static void main(String[] args) {
    		CardMachine machine = new CardMachine();
    		Screen screen = new Screen();
    		Speaker speaker = new Speaker();
    		machine.addPunchListener(screen);
    		machine.addPunchListener(speaker);
    		machine.punchCard();
    	}
    }

EventPunchCard

import java.util.Date;
    
    /**
     * 打卡事件<BR>
     * 在什么时间，由XX触发打卡这个操作（事件）
     * 
     * @author JiangWenLei
     * 
     */
    public class EventPunchCard {
    	private Object person; // 事件的来源，表示事件是由XX触发的
    	private Date time; // 记录事件发生的时间
    
    	public EventPunchCard(Date time, Object person) {
    		this.person = person;
    		this.time = time;
    	}
    
    	public Object getSource() {
    		return person;
    	}
    
    	public void setSource(Object person) {
    		this.person = person;
    	}
    
    	public Date getTime() {
    		return time;
    	}
    
    	public void setTime(Date time) {
    		this.time = time;
    	}
    
    }

EventPunchCardListener

/**
     * 监听接口：监听打开的一系列状态的接口
     * 
     * @author JiangWenLei
     * 
     */
    public interface EventPunchCardListener {
    	public void performPunch(EventPunchCard punch);
    }

Screen

/**
     * 打卡机的显示屏<BR>
     * 用于显示打卡后的状态
     * 
     * @author JiangWenLei
     * 
     */
    public class Screen implements EventPunchCardListener {
    	/**
    	 * 显示余额
    	 */
    	public void performPunch(EventPunchCard punch) {
    		System.out.print(punch.getTime() + " ");
    		System.out.println("您的余额为51 !");
    	}
    }

Speaker

/**
     * 打卡机的扬声器<BR>
     * 用于提醒打卡后的状态
     * 
     * @author JiangWenLei
     * 
     */
    public class Speaker implements EventPunchCardListener {
    	/**
    	 * 声音提醒
    	 */
    	public void performPunch(EventPunchCard punch) {
    		System.out.print(punch.getTime());
    		java.awt.Toolkit.getDefaultToolkit().beep();
    	}
    }