code: @Override
  	public void computeDistance(List<Point2D> obs, double[] distance) {
  		for( int i = 0; i < obs.size(); i++ ) {
  			distance[i] = computeDistance(obs.get(i));
  		}
  	}
docs: There are some situations where processing everything as a list can speed things up a lot.
  This is not one of them.