code: public boolean exists() throws APIException {
          HttpResponse response = client.head(getUrl());
          int status = response.getStatusLine().getStatusCode();
          if(status != 200 && status != 404) {
              throw APIException.fromHttpResponse(response);
          }
          return (200 == status);
      }
docs: Returns whether the file exists in the Data API
  @return true iff the file exists
  @throws APIException if there were any problems communicating with the DataAPI