docs: @Trivial
      private static String toKey(String name, String filterExpr, Object[] filterArgs, SearchControls cons) {
          int length = name.length() + filterExpr.length() + filterArgs.length + 200;
          StringBuffer key = new StringBuffer(length);
          key.append(name);
          key.append("|");
          key.append(filterExpr);
          String[] attrIds = cons.getReturningAttributes();
          for (int i = 0; i < filterArgs.length; i++) {
              key.append("|");
              key.append(filterArgs[i]);
          }
          if (attrIds != null) {
              for (int i = 0; i < attrIds.length; i++) {
                  key.append("|");
                  key.append(attrIds[i]);
              }
          }
          return key.toString();
      }