Angle from toAngleAxis for rotation problem

I am rotating a camera around an object as the object rotates so that the camera stays behind it.  I figured I could use toAngleAxis on the object's localRotation to get the angle needed for moving the camera.  However the angle is positive when I rotate in either direction.  The code below works for rotating left and if angle was negative it would work for rotating to the right.  The problem is I am not sure of a way to tell when toAngleAxis is returning an angle to the right or left of the original rotation.

      angle = camState.getFocus().getLocalRotation().toAngleAxis( new Vector3f(0,1,0) );

      x = camState.getCenter().x - distance*FastMath.sin( angle );
      z = camState.getCenter().z - distance*FastMath.cos( angle );
      camState.setLoc( x, y, z );
      camState.lookAt( camState.getFocus().getLoc(), Vector3f.UNIT_Y );