@Override
    @SuppressWarnings("unchecked")
    public void populateDAG(DAG dag, Configuration conf) {
      RandomWordGenerator randomWordGenerator = new RandomWordGenerator();
      randomWordGenerator.setTuplesPerWindow(2);

      dag.addOperator("random", randomWordGenerator);

      if (maxLength != null) {
        fsWriter.setMaxLength(maxLength);
      }

      fsWriter.setFilePath(testDir.getPath());
      dag.addOperator("fswriter", fsWriter);

      dag.addStream("fswriterstream", randomWordGenerator.output, fsWriter.input);
    }