isValidMsg static method
Checks whether the geometry buffer is valid, and returns an error message if not.
@param g @param distance @param result @return an appropriate error message or null if the buffer is valid
Implementation
static String? isValidMsg(Geometry g, double distance, Geometry result) {
BufferResultValidator validator =
new BufferResultValidator(g, distance, result);
if (!validator.isValid()) return validator.getErrorMessage();
return null;
}