ValidationTestFrame

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;
import javax.swing.text.*;
class ValidationTestFrame extends JFrame implements DocumentListener
{
public ValidationTestFrame()
{
setTitle("ValidationTest");
setSize(300, 200);
addWindowListener(new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
} );

Container contentPane = getContentPane();

JPanel p = new JPanel();
hourField = new IntTextField(12, 3);
p.add(hourField);
hourField.getDocument().addDocumentListener(this);

minuteField = new IntTextField(0, 3);
p.add(minuteField);
minuteField.getDocument().addDocumentListener(this);

contentPane.add(p, "South");
clock = new ClockPanel();
contentPane.add(clock, "Center");
}

public void insertUpdate(DocumentEvent e)
{ setClock();
}
public void removeUpdate(DocumentEvent e)
{ setClock();
}
public void changedUpdate(DocumentEvent e)
{
}

public void setClock()
{ if (hourField.isValid() && minuteField.isValid())
{ int hours = hourField.getValue();
int minutes = minuteField.getValue();
clock.setTime(hours, minutes);
}
}

private IntTextField hourField;
private IntTextField minuteField;
private ClockPanel clock;
}

class ClockPanel extends JPanel
{ public void paintComponent(Graphics g)
{ super.paintComponent(g);
g.drawOval(0, 0, 100, 100);
double hourAngle
= 2 * Math.PI * (minutes - 3 * 60) / (12 * 60);
double minuteAngle
= 2 * Math.PI * (minutes - 15) / 60;
g.drawLine(50, 50,
50 + (int)(30 * Math.cos(hourAngle)),
50 + (int)(30 * Math.sin(hourAngle)));
g.drawLine(50, 50,
50 + (int)(45 * Math.cos(minuteAngle)),
50 + (int)(45 * Math.sin(minuteAngle)));
}

public void setTime(int h, int m)
{ minutes = h * 60 + m;
repaint();
}

public void tick()
{ minutes++;
repaint();
}

private int minutes = 0;
}

public class ValidationTest
{ public static void main(String[] args)
{ JFrame frame = new ValidationTestFrame();
frame.show();
}
}

class IntTextDocument extends PlainDocument
{ public void insertString(int offs, String str,
AttributeSet a)
throws BadLocationException
{ if (str == null) return;
String oldString = getText(0, getLength());
String newString = oldString.substring(0, offs)
+ str + oldString.substring(offs);
try
{ Integer.parseInt(newString + "0");
super.insertString(offs, str, a);
}
catch(NumberFormatException e)
{
}
}
}

class IntTextField extends JTextField
{ public IntTextField(int defval, int size)
{ super("" + defval, size);
}

protected Document createDefaultModel()
{ return new IntTextDocument();
}

public boolean isValid()
{ try
{ Integer.parseInt(getText());
return true;
}
catch(NumberFormatException e)
{ return false;
}
}

public int getValue()
{ try
{ return Integer.parseInt(getText());
}
catch(NumberFormatException e)
{ return 0;
}
}
}