code: public void setSortOrder(final java.lang.String sortOrder) {
          // when updating, make sure we store off the original so it may be
          // restored
          final String orig = (String) getStateHelper().get(PropertyKeys.origSortOrder);
          if (orig == null) {
              // do not call getSortOrder as it defaults to ascending, we want
              // null
              // if this is the first call and there is no previous value.
              getStateHelper().put(PropertyKeys.origSortOrder, getStateHelper().eval(PropertyKeys.sortOrder));
          }
          getStateHelper().put(PropertyKeys.sortOrder, sortOrder);
      }
docs: Update the sort direction
  
  @param sortOrder