ClockCanvas.java

package com.godoro.samples.awt;

import java.awt.*;
import java.util.*;

public class ClockCanvas extends Canvas
{

  private final static int SLICE_DEGREE = 6;
  private Point center = new Point(100, 100);
  private int radius = 80;

  public ClockCanvas()
  {
    Timer timer = new Timer();
    TimerTask task = new TimerTask()
    {
      public void run()
      {
        repaint();
      }
    };
    timer.scheduleAtFixedRate(task, 0, 1000);
  }
  public void paint(Graphics g)
  {
    Calendar now = Calendar.getInstance();
    drawDial(g);
    drawSecondHand(g, now);
    drawMinuteHand(g, now);
    drawHourHand(g, now);
  }

  private void drawDial(Graphics g)
  {
    g.drawOval(center.x - radius, center.y - radius, 2 * radius, 2 * radius);
    int numbersRadius = radius - 8;
    for (int i = 1; i <= 12; i++) {
      double hour = Math.PI / 6;
      int x = (int) (center.x - 5 + (numbersRadius) * Math.sin(i * hour));
      int y = (int) (center.x + 5 - (numbersRadius) * Math.cos(i * hour));
      g.drawString(Integer.toString(i), x, y);
    }
  }

  private void drawSecondHand(Graphics g, Calendar now)
  {
    int second = now.get(Calendar.SECOND);
    double radian = Math.toRadians(SLICE_DEGREE * second);
    int x = (int) (center.x + (radius - 5) * Math.sin(radian));
    int y = (int) (center.y - (radius - 5) * Math.cos(radian));
    g.drawLine(center.x, center.y, x, y);
  }

  private void drawMinuteHand(Graphics g, Calendar now)
  {
    int minute = now.get(Calendar.MINUTE);
    double radian = Math.toRadians(SLICE_DEGREE * minute);
    int x = (int) (center.x + (radius - 10) * Math.sin(radian));
    int y = (int) (center.y - (radius - 10) * Math.cos(radian));
    g.drawLine(center.x, center.y, x, y);
  }

  private void drawHourHand(Graphics g, Calendar now)
  {
    int hour = now.get(Calendar.HOUR);
    int minute = now.get(Calendar.MINUTE);
    double radian = Math.toRadians(30 * hour + minute / 2);
    int x = (int) (center.x + (radius - 25) * Math.sin(radian));
    int y = (int) (center.y - (radius - 25) * Math.cos(radian));
    g.drawLine(center.x, center.y, x, y);
  }

  public static void main(String[] args)
  {
    Frame frame = new Frame();
    frame.setTitle("Clock Canvas");
    frame.setLayout(new BorderLayout());
    frame.add(BorderLayout.CENTER, new ClockCanvas());
    frame.setBounds(0, 0, 220, 220);
    frame.setVisible(true);
  }
}