code: public String getPropertyAsString(Object data) throws ODataException {
          LOG.trace("GetPropertyAsString invoked with {}", data);
          if (data != null) {
              return makePropertyString(data);
          } else {
              return generateNullPropertyString();
          }
      }
docs: This is main method to get property as string.
  
  @param data represents simple primitive or complex value or collections of collection of these.
  @return String that represents simple primitive or complex value
  or collections of collection of these in the form of xml or json.
  @throws ODataException if an error occurs.