JSPinner and floating point quirk

Question

Please test these spinners only with their down arrow buttons to reach minimum value of each. When the number of fraction columns are 5,10 and 12, spinner stops at one step before the real minimum. They don't go to the real minimum. Why could this happen?
import javax.swing.*;
import java.text.*;
public class SpinnerQuirk{
  public static void main(String[] args){
    Box panel = new Box(BoxLayout.X_AXIS);
    double fraction = 0.01;
    double base = 1.0;
    String fmt = "#0.00";
    for (int i = 2; i < 14; ++i){
      DecimalFormat df = new DecimalFormat(fmt);
      Box box = new Box(BoxLayout.Y_AXIS);
      JSpinner spinner = new JSpinner();
      SpinnerNumberModel spinnerModel
        = new SpinnerNumberModel(base + fraction,
                                 base + fraction - fraction * 101,
                                 base + fraction + fraction * 99,
                                 fraction);
      spinner.setModel(spinnerModel);
      spinner.setEditor(new JSpinner.NumberEditor(spinner, fmt));
      JLabel label = new JLabel("min = "
          + df.format((base + fraction - fraction * 101)));
      box.add(spinner);
      box.add(label);
      panel.add(box);
      fraction = fraction / 10.0;
      fmt += "0";
    JOptionPane.showMessageDialog(null, panel);
    System.exit(0);
}

Answer 1

Thanks. I think I have found the root cause of the problem. That is, there's no effective communications between java.text formatting and javax.swing.text one(*). A bad example of a bureaucratic sectionalism at Sun?
(*: Because DecimalFormat does the right job given the same format string and same value.)
Japanese: tate wari
Englisn: divided vertically
Edited by: hiwa on Oct 5, 2007 11:18 AM