@Override
    public void assignAxis(String positiveMapping, String negativeMapping) {
        if (axisIndex != -1) {
            inputManager.addMapping(positiveMapping, new JoyAxisTrigger(parent.getJoyId(), axisIndex, false));
            inputManager.addMapping(negativeMapping, new JoyAxisTrigger(parent.getJoyId(), axisIndex, true));
        }
    }
Assign the mappings to receive events from the given joystick axis.

 @param positiveMapping The mapping to receive events when the axis is negative
 @param negativeMapping The mapping to receive events when the axis is positive
jme3-core/src/main/java/com/jme3/input/DefaultJoystickAxis.java