code: public int countSubColumns(K key, SN superColumnName, N start,
        N end, int max) {
      SubCountQuery<K, SN, N> query = HFactory.createSubCountQuery(
          keyspace, keySerializer, topSerializer, subSerializer);
      query.setKey(key);
      query.setColumnFamily(columnFamily);
      query.setSuperColumn(superColumnName);
      query.setRange(start, end, max);
      return query.execute().get();
    }
docs: Counts child columns in the specified range of a children in a specified
  super column
  
  @param key
  @param superColumnName
  @param start
  @param end
  @param max
  @return