JSpinner - Increment or decrement button pressed?

Question

Hi Folks,
I have a JSpinner component which can only be updated through the increment/decrement buttons.
To validate the value before updating the UI, I need to verify the next value. So how do I determine if the user clicked the increment or the decrement button?
Also, the sequence of valid values that the JSpinner can display is not linear but changes based on the previous value.
For eg, the valid values are 4, 5, 8, 12, 17.. to a max of 300
Thanks

Answer 1

Thanks for that link Michael. It helped a bit.. However, I'm stuck in the checkChange method. My slightly modified code is as follows:
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
class Testing
     JSpinner spinner;
     final int MIN = 0, MAX = 100;
     public void buildGUI()
          JPanel p = new JPanel();
          spinner = new JSpinner(new SpinnerNumberModel(MIN,MIN,MAX,1));
          ((JSpinner.DefaultEditor)spinner.getEditor()).getTextField().setEditable(false);
          spinner.setUI(new ChangeVerifierUI());
          p.add(spinner);
          JFrame f = new JFrame();
          f.getContentPane().add(p);
          f.pack();
          f.setLocationRelativeTo(null);
          f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
          f.setVisible(true);
     class ChangeVerifierUI extends javax.swing.plaf.basic.BasicSpinnerUI
          protected Component createNextButton()
               JButton nextButton = (JButton)super.createNextButton();
               nextButton.removeMouseListener(nextButton.getMouseListeners()[0]);
               nextButton.addMouseListener(new MouseAdapter(){
                    public void mousePressed(MouseEvent me){
                         if(((Integer)spinner.getValue()).intValue() < MAX) checkChange(+1);
               return nextButton;
          protected Component createPreviousButton()
               JButton previousButton = (JButton)super.createPreviousButton();
               previousButton.removeMouseListener(previousButton.getMouseListeners()[0]);
               previousButton.addMouseListener(new MouseAdapter(){
                    public void mousePressed(MouseEvent me){
                         if(((Integer)spinner.getValue()).intValue() > MIN) checkChange(-1);
               return previousButton;
     public void checkChange(int direction)
//          int result = JOptionPane.showConfirmDialog(null,"Are you sure you want to row setting ?",
//                    "Setup", JOptionPane.YES_NO_OPTION,JOptionPane.QUESTION_MESSAGE);
          System.out.println("Verification code comes here");
//Only to create delay for standalone testing
          for(int i=0; i<1000; i++) {
               for (int j=0; j<10000; j++) {
                    int ttemp = i*j;
//          if (result == JOptionPane.YES_OPTION) spinner.setValue(
//                    ((Integer)spinner.getValue()).intValue()+
//                    (((Number)((SpinnerNumberModel)spinner.getModel()).getStepSize()).intValue())*direction);
     public static void main(String[] args)
          SwingUtilities.invokeLater(new Runnable(){
               public void run(){
                    new Testing().buildGUI();
}I noticed that the sys-out prints only once and then the JSpinner value continues to increment. How would one modify that behavior to say print (or in the actual case, make a call on a library for verification of the value) for each increment before the value is set on the UI?
Thanks a lot for your help so far :)