public  void addChangeListener(ChangeListener l) 
{
        listenerList.add(ChangeListener.class, l);
}

Adds a ChangeListener to the button.

 public  void clearSelection() 
{
        setSelectedIndex(-1);
}

 protected  void fireStateChanged() 
{
        // 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]==ChangeListener.class) {
                // Lazily create the event:
                if (changeEvent == null)
                    changeEvent = new ChangeEvent(this);
                ((ChangeListener)listeners[i+1]).stateChanged(changeEvent);
            }
        }
}

Notifies all listeners that have registered interest for notification on this event type. The event instance is created lazily.

 public ChangeListener[] getChangeListeners() 
{
        return (ChangeListener[])listenerList.getListeners(
                ChangeListener.class);
}

Returns an array of all the change listeners registered on this DefaultSingleSelectionModel.

 public T[] getListeners(Class listenerType) 
{
        return listenerList.getListeners(listenerType);
}

Returns an array of all the objects currently registered as FooListeners upon this model. FooListeners are registered using the addFooListener method.

You can specify the listenerType argument with a class literal, such as FooListener.class. For example, you can query a DefaultSingleSelectionModel instance m for its change listeners with the following code:

ChangeListener[] cls = (ChangeListener[])(m.getListeners(ChangeListener.class));

If no such listeners exist, this method returns an empty array.

 public int getSelectedIndex() 
{
    // implements javax.swing.SingleSelectionModel
        return index;
}

 public boolean isSelected() 
{
        boolean ret = false;
        if (getSelectedIndex() != -1) {
            ret = true;
        }
        return ret;
}

 public  void removeChangeListener(ChangeListener l) 
{
        listenerList.remove(ChangeListener.class, l);
}

Removes a ChangeListener from the button.

 public  void setSelectedIndex(int index) 
{
        if (this.index != index) {
            this.index = index;
            fireStateChanged();
        }
}