@Override
    protected void
      setup(Mapper<ImmutableBytesWritable, Result, ImmutableBytesWritable, Result>.Context context)
        throws IOException, InterruptedException {
      Configuration conf = context.getConfiguration();
      countDeleteMarkers = conf.getBoolean(OPT_COUNT_DELETE_MARKERS, false);
    }
Counter enumeration to count the actual rows, cells and delete markers.
hbase-mapreduce/src/main/java/org/apache/hadoop/hbase/mapreduce/RowCounter.java