@Override
  protected void processOldArgs(List<String> args) {
    List<String> copiedArgs = new ArrayList<>(args);
    args.removeAll(copiedArgs);
    for (String arg : copiedArgs) {
      if (arg.startsWith("-") && arg.contains("=")) {
        String[] kv = arg.split("=");
        args.add(kv[0]);
        args.add(kv[1]);
      } else {
        args.add(arg);
      }
    }
  }
Sets filter {@link FilterBase} to the {@link Scan} instance. If provided rowRangeList contains
more than one element, method sets filter which is instance of {@link MultiRowRangeFilter}. If
rowRangeList contains exactly one element, startRow and stopRow are set to the scan. Also,
method may apply {@link FirstKeyOnlyFilter} an {@link KeyOnlyFilter} for better performance.
hbase-mapreduce/src/main/java/org/apache/hadoop/hbase/mapreduce/RowCounter.java