code: public static GISModel trainModel(EventStream eventStream,
          int iterations,
          int cutoff,
          boolean smoothing,boolean printMessagesWhileTraining) {
        GISTrainer trainer = new GISTrainer(printMessagesWhileTraining);
        trainer.setSmoothing(smoothing);
        trainer.setSmoothingObservation(SMOOTHING_OBSERVATION);
        return trainer.trainModel(eventStream, iterations, cutoff);
      }
docs: Train a model using the GIS algorithm.
  @param eventStream The EventStream holding the data on which this model
  will be trained.
  @param iterations  The number of GIS iterations to perform.
  @param cutoff      The number of times a feature must be seen in order
  to be relevant for training.
  @param smoothing   Defines whether the created trainer will use smoothing
  while training the model.
  @param printMessagesWhileTraining Determines whether training status messages are written to STDOUT.
  @return The newly trained model, which can be used immediately or saved
  to disk using an opennlp.maxent.io.GISModelWriter object.