public boolean isNegative() {
        return negative;
    }
Create a new <code>MouseAxisTrigger</code>.
<p>
@param mouseAxis Mouse axis. See AXIS_*** constants in {@link MouseInput}
@param negative True if listen to negative axis events, false if
listen to positive axis events.
jme3-core/src/main/java/com/jme3/input/controls/MouseAxisTrigger.java