@Override
  public void doTransform(FeatureVector featureVector) {
    Map<String, Map<String, Double>> floatFeatures = featureVector.getFloatFeatures();
    if (floatFeatures == null) {
      return;
    }
    Map<String, Double> feature1 = floatFeatures.get(fieldName1);
    if (feature1 == null || feature1.isEmpty()) {
      return;
    }

    Util.optionallyCreateStringFeatures(featureVector);
    Map<String, Set<String>> stringFeatures = featureVector.getStringFeatures();
    Set<String> output = Util.getOrCreateStringFeature(outputName, stringFeatures);

    for (Entry<String, Double> feature : feature1.entrySet()) {
      output.add(logQuantize(feature.getKey(), feature.getValue()));
    }
  }