can't get rid of 1st typed character

[Gary Frick]

I'm trying to limit input to only numerics, but when I try to stop the character from appearing, I am only successful with characters beyond the first one. I can't figure out why the event is getting through and the first character always remains.

public class keyCheckHandler implements KeyListener{
    
    public void keyPressed(java.awt.event.KeyEvent keyEvent) {
       int key = keyEvent.getKeyCode();
       boolean badvalue = false;
       JTextField keysrc;
       keysrc = (JTextField)keyEvent.getComponent();
       keysrc.getClass();
       switch(key)
       {
           case KeyEvent.VK_BACK_SPACE: break;
           case KeyEvent.VK_DELETE: break;
           default:
           {
             if (( key < 48) ^ (key > 57))
             {
              badvalue = true;
              keyEvent.consume();
             }
             break;
           }
       }
    if (badvalue)
    {
     if( keysrc.getText().length() > 0)
          keysrc.setText(keysrc.getText().substring(0, keysrc.getText().length() - 1));
          else keysrc.setText(null);
    }
   }

Thanks

[alagan sathianathan]

Why dont you try using Document class:
IntegerField allows only numeric fields

public class IntegerField extends JTextField
{
    public int constraint;
    public IntegerField(int i, int j)
    {
        super(i);
        constraint = j;
        detDocument(new NumericDocument(constraint));
                }
   
}

Document class:

import javax.swing.text.*;
public class NumericDocument extends PlainDocument
{
    public int constraint;
    protected NumericDocument(int i)
    {
        constraint = i;
    }
    public void insertString(int i, String s, AttributeSet attributeset)
        throws BadLocationException
    {
        if(s == null)
        {
            return;
        }
        char ac[] = s.toCharArray();
        boolean flag = true;
        boolean flag1 = true;
        if(ac.length + getLength() <= constraint)
        {
            for(int j = 0; j < ac.length; j++)
            {
                if(Character.isDigit(ac[j]))
                {
                    continue;
                }
                flag = false;
                break;
            }
        } else
        {
            flag1 = false;
        }
        if(flag1 && flag)
        {
            super.insertString(i, s, attributeset);
        }
    }
}