code: public String print(
          ChronoPrinter<T> printer,
          String intervalPattern
      ) {
  
          AttributeQuery attrs = printer.getAttributes();
          StringBuilder sb = new StringBuilder(32);
          int i = 0;
          int n = intervalPattern.length();
  
          while (i < n) {
              char c = intervalPattern.charAt(i);
              if ((c == '{') && (i + 2 < n) && (intervalPattern.charAt(i + 2) == '}')) {
                  char next = intervalPattern.charAt(i + 1);
                  if (next == '0') {
                      printer.print(this.t1, sb, attrs);
                      i += 3;
                      continue;
                  } else if (next == '1') {
                      printer.print(this.t2, sb, attrs);
                      i += 3;
                      continue;
                  }
              }
              sb.append(c);
              i++;
          }
  
          return sb.toString();
  
      }
docs: /*[deutsch]
  <p>Formatiert dieses Intervall in einem benutzerdefinierten Format. </p>
  
  @param   printer             format object for printing start and end components
  @param   intervalPattern     interval pattern containing placeholders {0} and {1} (for start and end)
  @return  formatted string in given pattern format