clock.java

Java程序设计技巧与开发实例附书源代码。

import java.awt.Label;
import java.util.Date;

public class Clock
        extends Label
        implements Runnable {
    private Thread clocker = null;

    public Clock() {
        setText(new Date().toString());
    }

    public void start() {
        if (clocker == null) {
            clocker = new Thread(this);
            clocker.start();
        }
    }

    public void stop() {
        clocker = null;
    }

    public void run() {
        Thread currentThread = Thread.currentThread();
        while (clocker == currentThread) {
            setText(new Date().toString());
            try {
                clocker.sleep(1000);
            }
            catch (InterruptedException ie) {
                setText("Clock broken");
            }
        }
    }
}