Java by API/java.beans/VetoableChangeListener

implements VetoableChangeListener

   <source lang="java">

import java.awt.BorderLayout; import java.beans.PropertyChangeEvent; import java.beans.PropertyVetoException; import java.beans.VetoableChangeListener; import javax.swing.JDesktopPane; import javax.swing.JFrame; import javax.swing.JInternalFrame; public class MainClass {

 public static void main(final String args[]) {
   JFrame frame = new JFrame();
   frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
   JDesktopPane desktop = new JDesktopPane();
   JInternalFrame palette = new JInternalFrame("Palette", true, true, true,
       true);
   
   palette.addVetoableChangeListener(new IconPolice());
   
   palette.setBounds(350, 150, 100, 100);
    desktop.add(palette, JDesktopPane.PALETTE_LAYER);
   palette.setVisible(true);
   
   frame.add(desktop, BorderLayout.CENTER);
   frame.setSize(500, 300);
   frame.setVisible(true);
 }

} class IconPolice implements VetoableChangeListener {

 public void vetoableChange(PropertyChangeEvent ev) throws PropertyVetoException {
   String name = ev.getPropertyName();
   if (name.equals(JInternalFrame.IS_ICON_PROPERTY) && (ev.getNewValue() == Boolean.TRUE)) {
  System.out.println("JInternalFrame.IS_ICON_PROPERTY"); 
   }
 }

}

      </source>