docs: private Object getObjectValue(String fieldname, boolean fromSource) throws Exception {
          Object sourceObject = fromSource ? source : target;
          Object result = null;
          for (String part : StringUtils.split(fieldname, ".")) {
              if (isTemporaryField(part)) {
                  result = loadObjectFromTemporary(part, fieldname);
              } else {
                  result = loadObjectFromField(part, result, sourceObject);
              }
          }
          return result;
      }