// -------->
 // original code:
 // ftp://ftp.oreilly.de/pub/examples/english_examples/jswing2/code/goodies/Mapper.java
 // modified by terai
 //     private Hashtable<Object, ArrayList<KeyStroke>> buildReverseMap(InputMap im) {
 //         Hashtable<Object, ArrayList<KeyStroke>> h = new Hashtable<>();
 //         if (Objects.isNull(im.allKeys())) {
 //             return h;
 //         }
 //         for (KeyStroke ks: im.allKeys()) {
 //             Object name = im.get(ks);
 //             if (h.containsKey(name)) {
 //                 h.get(name).add(ks);
 //             } else {
 //                 ArrayList<KeyStroke> keylist = new ArrayList<>();
 //                 keylist.add(ks);
 //                 h.put(name, keylist);
 //             }
 //         }
 //         return h;
 //     }
 private void loadBindingMap(Integer focusType, InputMap im, ActionMap am) {
   if (Objects.isNull(im.allKeys())) {
     return;
   }
   ActionMap tmpAm = new ActionMap();
   for (Object actionMapKey : am.allKeys()) {
     tmpAm.put(actionMapKey, am.get(actionMapKey));
   }
   for (KeyStroke ks : im.allKeys()) {
     Object actionMapKey = im.get(ks);
     Action action = am.get(actionMapKey);
     if (Objects.isNull(action)) {
       model.addBinding(new Binding(focusType, "____" + actionMapKey.toString(), ks.toString()));
     } else {
       model.addBinding(new Binding(focusType, actionMapKey.toString(), ks.toString()));
     }
     tmpAm.remove(actionMapKey);
   }
   if (Objects.isNull(tmpAm.allKeys())) {
     return;
   }
   for (Object actionMapKey : tmpAm.allKeys()) {
     model.addBinding(new Binding(focusType, actionMapKey.toString(), ""));
   }
 }
 protected void fireEditingCanceled() {
   // Guaranteed to return a non-null array
   Object[] listeners = listenerList.getListenerList();
   // Process the listeners last to first, notifying
   // those that are interested in this event
   for (int i = listeners.length - 2; i >= 0; i -= 2) {
     if (listeners[i] == CellEditorListener.class) {
       // Lazily create the event:
       if (Objects.isNull(changeEvent)) {
         changeEvent = new ChangeEvent(this);
       }
       ((CellEditorListener) listeners[i + 1]).editingCanceled(changeEvent);
     }
   }
 }
 @Override
 public void mouseMoved(MouseEvent e) {
   // JList list = (JList) e.getComponent();
   Point pt = e.getPoint();
   int index = list.locationToIndex(pt);
   if (!list.getCellBounds(index, index).contains(pt)) {
     if (prevIndex >= 0) {
       listRepaint(list, list.getCellBounds(prevIndex, prevIndex));
     }
     index = -1;
     prevButton = null;
     return;
   }
   if (index >= 0) {
     JButton button = getButton(list, pt, index);
     ButtonsRenderer renderer = (ButtonsRenderer) list.getCellRenderer();
     renderer.button = button;
     if (Objects.isNull(button)) {
       renderer.rolloverIndex = -1;
       Rectangle r = null;
       if (prevIndex == index) {
         if (prevIndex >= 0 && Objects.nonNull(prevButton)) {
           r = list.getCellBounds(prevIndex, prevIndex);
         }
       } else {
         r = list.getCellBounds(index, index);
       }
       listRepaint(list, r);
       prevIndex = -1;
     } else {
       button.getModel().setRollover(true);
       renderer.rolloverIndex = index;
       if (!button.equals(prevButton)) {
         listRepaint(list, list.getCellBounds(prevIndex, index));
       }
     }
     prevButton = button;
   }
   prevIndex = index;
 }