@Override
    public void setLastRow(String userInput) {
      lastRow = userInput;
      lastRowInt = new BigInteger(lastRow, radix);
      // Precondition: lastRow > firstRow, so last's length is the greater
      rowComparisonLength = lastRow.length();
    }
The format of a DecimalStringSplit region boundary is the ASCII representation of reversed
sequential number, or any other uniformly distributed decimal value. Row are decimal-encoded
long values in the range <b>"00000000" =&gt; "99999999"</b> and are left-padded with zeros to
keep the same order lexicographically as if they were binary.
hbase-server/src/main/java/org/apache/hadoop/hbase/util/RegionSplitter.java