docs: private static String shortCut(String name, int level) {
          String sa[] = name.split(NAME_PART_SEPARATOR);
          if (sa.length < 2) {
              return null;
          }
          S.Buffer sb = S.buffer();
          switch (level) {
              case 0:
                  sb.append(".");
                  for (String s : sa) {
                      sb.append(s.charAt(0));
                  }
                  return sb.toString();
              case 1:
                  for (String s : sa) {
                      sb.append(s.charAt(0)).append(".");
                  }
                  sb.deleteCharAt(sb.length() - 1);
                  return sb.toString();
              case 2:
                  for (int i = 0; i < sa.length - 1; ++i) {
                      sb.append(sa[i].charAt(0)).append(".");
                  }
                  sb.append(sa[sa.length - 1]);
                  return sb.toString();
              case 3:
                  for (int i = 0; i < sa.length - 2; ++i) {
                      sb.append(sa[i].charAt(0)).append(".");
                  }
                  sb.append(sa[sa.length - 2]).append(".");
                  sb.append(sa[sa.length - 1].charAt(0));
                  return sb.toString();
              case 4:
                  for (String s : sa) {
                      sb.append(s.charAt(0));
                      if (s.length() > 1) {
                          sb.append(s.charAt(1));
                      }
                      sb.append(".");
                  }
                  sb.deleteCharAt(sb.length() - 1);
                  return sb.toString();
              default:
                  throw E.unsupport();
          }
      }