code: public void setCoordinate(Coordinate coordinate) {
  		if (coordinate == null) {
  			throw new IllegalArgumentException("Can't snap to a null coordinate.");
  		}
  		this.coordinate = coordinate;
  		bounds = new Bbox(coordinate.getX() - rule.getDistance(), coordinate.getY() - rule.getDistance(), rule
  				.getDistance() * 2, rule.getDistance() * 2);
  		distance = Double.MAX_VALUE;
  		snappedCoordinate = coordinate;
  	}
docs: Set a new coordinate ready to be snapped.