public int getColumnOffset(int idx) {
        if (idx > 0) return tabOffsets.get(idx - 1) + 1;
        else return 0;
      }
@param columnsSpecification the list of columns to parser out, comma separated. The row key
                            should be the special token TsvParser.ROWKEY_COLUMN_SPEC
hbase-mapreduce/src/main/java/org/apache/hadoop/hbase/mapreduce/ImportTsv.java