Review

class NumericUtils {
  /** Helper that delegates to correct range builder */
  private static void addRange(
    final Object builder, final int valSize,
    long minBound, long maxBound,
    final int shift
  ) {
    // for the max bound set all lower bits (that were shifted away):
    // this is important for testing or other usages of the splitted range
    // (e.g. to reconstruct the full range). The prefixEncoding will remove
    // the bits anyway, so they do not hurt!
    maxBound |= (1L << shift) - 1L;
    // delegate to correct range builder
    switch(valSize) {
      case 64:
        ((LongRangeBuilder)builder).addRange(minBound, maxBound, shift);
        break;
      case 32:
        ((IntRangeBuilder)builder).addRange((int)minBound, (int)maxBound, shift);
        break;
      default:
        // Should not happen!
        throw new IllegalArgumentException("valSize must be 32 or 64.");
    }
  }

}