code: public Counter<L> scoresOf(Datum<L, F> example) {
      if(example instanceof RVFDatum<?, ?>)return scoresOfRVFDatum((RVFDatum<L,F>)example);
      Collection<F> feats = example.asFeatures();
      int[] features = new int[feats.size()];
      int i = 0;
      for (F f : feats) {
        int index = featureIndex.indexOf(f);
        if (index >= 0) {
          features[i++] = index;
        } else {
          //System.err.println("FEATURE LESS THAN ZERO: " + f);
        }
      }
      int[] activeFeatures = new int[i];
      System.arraycopy(features, 0, activeFeatures, 0, i);
      Counter<L> scores = new ClassicCounter<L>();
      for (L lab : labels()) {
        scores.setCount(lab, scoreOf(activeFeatures, lab));
      }
      return scores;
    }
docs: Construct a counter with keys the labels of the classifier and
  values the score (unnormalized log probability) of each class.