code: protected Object getRequestData() throws ActivityException {
          String varname = getAttributeValue(REQUEST_VARIABLE);
          Object request = varname == null ? null : getParameterValue(varname);
          if (!StringHelper.isEmpty(getPreScript())) {
              Object returnVal = executePreScript(request);
              if (returnVal == null) {
                  // nothing returned; requestVar may have been assigned by script
                  request = getParameterValue(varname);
              }
              else {
                  request = returnVal;
              }
          }
          return request;
      }
docs: Override this method if need to translate data from variable
  or need to get data elsewhere. The default
  method assumes the data is in the variable REQUEST_VARIABLE
  
  Also, if a translation is needed to convert data in internal
  format to one required by external system, this is the place
  for doing it.
  
  @return
  @throws ActivityException when the attribute cannot be
  fetched for any reason
  @throws TranslationException if the request cannot be translated correctly. This
  is a RuntimeException