10 seconds countdown on console

I wrote this program for a simple count down program. It compiles but nothing happens. Where have i gone wrong. I've never used Timers before:

Code:

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import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.Timer;

public class timer implements ActionListener{
       
        Timer t;
        private int countdownPeriod = 0;
        private final int ONE_SECOND = 1000;
        private void write()
        {
                System.out.printf("%s, ", this.countdownPeriod);
        }
       
        public timer(int seconds)
        {
                this.countdownPeriod=seconds;
                t = new Timer(this.ONE_SECOND,this);
                t.setInitialDelay(0);
                t.start();
        }

        @Override
        public void actionPerformed(ActionEvent arg0) {
                // TODO Auto-generated method stub
                if(this.countdownPeriod==0)
                {
                        t.stop();
                }else{
                        this.countdownPeriod--;
                        write();
                }
        }
       
        public static void main(String args[])
        {
                timer tom = new timer(10);
        }

}

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If you want a Timer in a non-GUI application, then don't use a Swing Timer (or javax.swing.Timer), but instead use a util Timer or java.util.Timer.

Having said that, some of your code would work with a simple Swing GUI:

Code:

---

import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.swing.JLabel;
import javax.swing.JOptionPane;
import javax.swing.Timer;

public class MyTimer implements ActionListener {
  private JLabel timerLabel = new JLabel("    ");

  Timer t;
  private int countdownPeriod = 0;
  private final int ONE_SECOND = 1000;

  private void write() {
      //!! System.out.printf("%s, ", this.countdownPeriod);
      timerLabel.setText("" + countdownPeriod);
  }

  public MyTimer(int seconds) {
      this.countdownPeriod = seconds;
      timerLabel.setText("" + countdownPeriod);
      t = new Timer(this.ONE_SECOND, this);
      //t.setInitialDelay(0);
      t.start();
      JOptionPane.showMessageDialog(null, timerLabel);
  }

  @Override
  public void actionPerformed(ActionEvent arg0) {
      if (this.countdownPeriod == 0) {
        t.stop();
      } else {
        this.countdownPeriod--;
        write();
      }
  }

  public static void main(String args[]) {
      MyTimer tom = new MyTimer(10);
  }

}

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So a swing timer won't work if there isn't as gui?

Quote:

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Originally Posted by eLancaster

So a swing timer won't work if there isn't as gui?

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Correct. You need to initiate the main Swing thread and have it persist as in my example above. But the other java.util.Timer is important to learn to use too.

Thanks! Don't worry - i hope to get atleast a hang of both over the weekend :)