public  void init(PropertyDescriptor descriptor) 
{
        if (textfield == null)
        {
            textfield = new JTextField();
            textfield.setDocument(new FloatNumberDocument());
            // disable editing if its a readonly property
            if( descriptor.getWriteMethod() == null ) textfield.setEditable( false );
            textfield.addActionListener(new ActionListener()
            {
                public void actionPerformed(ActionEvent e)
                {
                    String text = textfield.getText();
                    if( text.length() == 0 ) text = "0";
                    setValue(new Double(text));
                }
            });
            panel = new JPanel();
            panel.setLayout(new BoxLayout(panel, BoxLayout.X_AXIS));
            panel.add(textfield);
        }
}

Initializes this property editor

 public  void setValue(Object value) 
{
        if (value != null)  {
            textfield.setText(value.toString());
        }
        super.setValue(value);
}