code: private ExampleSet readDataSet(File in) throws IOException
  	{
  		logger.info("read the example set");
  
  		//
  		ExampleSet inputSet = new SentenceSetCopy();
  		inputSet.read(new BufferedReader(new FileReader(in)));
  
  		String trainFrac = parameter.getProperty("train-frac");
  		if (trainFrac != null)
  		{
  			double f = Double.parseDouble(trainFrac);
  			logger.info("training original size: " + inputSet.size());
  			logger.info("training fraction: " + (100 * f) + "%");
  			return inputSet.subSet(0, (int) (inputSet.size() * f));
  		}
  
  		return inputSet;
  	}
docs: read the data set