使用 ScheduledExecutorService 调度 Applet 启动

Question

I have a simple Clock Applet that I would like to be able to control via the ScheduledExecutorService, however I'm a little unsure as to how to make the thread start with the ScheduledExecutorService.schedule command.

import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

public class UpdateApplet extends java.applet.Applet implements Runnable
{

    ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);

    Thread thread;
    boolean running;
    int updateInterval = 1000;

    final Runnable clock = new Runnable(){//Can't take credit for this, thnx KH
        public void run(){
            while(true)
                repaint();
        }
    };

    public void run( ){
        scheduler.schedule(clock, 10, TimeUnit.SECONDS);//edited this here
    }

    public void start( ){
        System.out.println("starting...");
        if ( !running) //naive approach
        {
            running = true;
            thread = new Thread(this);
            thread.start( );
        }
    }

    public void stop( ){
        System.out.println("stopping...");
        thread.interrupt( );
        running = false;
    }
}

public class Clock extends UpdateApplet{

    public void paint(java.awt.Graphics g){
        g.drawString(new java.util.Date( ).toString( ), 10, 25);
    }

}

I'm sure its a simple fix, but I just don't see it. Any help will be greatly appreciated.

Answer 1

You need to use scheduleAtFixedRate . As well, you don't need to use a thread within the run method,

class UpdateApplet() implements Runnable {
    ScheduledExecutorService scheduler = Executors.newScheduledThreadPool(1);
    volatile boolean running;
    int updateInterval = 1000;

    public void start() {
       scheduler.schedule(this, updateInterval, updateInterval, TimeUnit.MILLISECONDS);
    }

    public void run() {
         if(!running) {
             scheduler.shutdown();
         }
         else {
              repaint();
         }
    }
}