code: boolean setIndexedField(ReadablePeriod period, int index, int[] values, int newValue) {
          int realIndex = iIndices[index];
          if (realIndex == -1) {
              throw new UnsupportedOperationException("Field is not supported");
          }
          values[realIndex] = newValue;
          return true;
      }
docs: Sets the indexed field part of the period.
  
  @param period  the period to query
  @param index  the index to use
  @param values  the array to populate
  @param newValue  the value to set
  @throws UnsupportedOperationException if not supported