code: private FilterList onFindKeyOnly(FilterList filterList, boolean isFindKeyOnly)
      {
          if (isFindKeyOnly)
          {
              if (filterList == null)
              {
                  filterList = new FilterList();
              }
              filterList.addFilter(new KeyOnlyFilter());
          }
          return filterList;
      }
docs: On find key only.
  
  @param filterList
  the filter list
  @param isFindKeyOnly
  the is find key only
  @return the filter list