code: public static Geometry convexHull(Geometry geometry) {
  		OperatorConvexHull op = (OperatorConvexHull) factory
  				.getOperator(Operator.Type.ConvexHull);
  		return op.execute(geometry, null);
  	}
docs: Calculates the convex hull geometry.
  
  See OperatorConvexHull.
  
  @param geometry The input geometry.
  @return Returns the convex hull.
  
  For a Point - returns the same point. For an Envelope -
  returns the same envelope. For a MultiPoint - If the point
  count is one, returns the same multipoint. If the point count
  is two, returns a polyline of the points. Otherwise computes
  and returns the convex hull polygon. For a Segment - returns a
  polyline consisting of the segment. For a Polyline - If
  consists of only one segment, returns the same polyline.
  Otherwise computes and returns the convex hull polygon. For a
  Polygon - If more than one path, or if the path isn't already
  convex, computes and returns the convex hull polygon.
  Otherwise returns the same polygon.