@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())); } }