code: public static Bson geoWithinPolygon(final String fieldName, final List<List<Double>> points) {
          BsonArray pointsArray = new BsonArray();
          for (List<Double> point : points) {
              pointsArray.add(new BsonArray(asList(new BsonDouble(point.get(0)), new BsonDouble(point.get(1)))));
          }
          BsonDocument polygon = new BsonDocument("$polygon", pointsArray);
          return new OperatorFilter<BsonDocument>("$geoWithin", fieldName, polygon);
      }
docs: Creates a filter that matches all documents containing a field with grid coordinates data that exist entirely within the specified
  polygon.
  
  @param fieldName the field name
  @param points    a list of pairs of x, y coordinates.  Any extra dimensions are ignored
  @return the filter
  @mongodb.driver.manual reference/operator/query/geoWithin/ $geoWithin
  @mongodb.driver.manual reference/operator/query/polygon/#op._S_polygon $polygon
  @mongodb.server.release 2.4
  @since 3.1