@Override
    public String toString() {
        return "JoystickButton[name=" + getName() + ", parent=" + parent.getName() + ", id=" + getButtonId()
                                    + ", logicalId=" + getLogicalId() + "]";
    }
Returns the unique buttonId of this joystick axis within a given
 InputManager context.

 @return the buttonId of this joystick axis.
jme3-core/src/main/java/com/jme3/input/DefaultJoystickButton.java