private static void writeSentences(TextAnnotation ta, JsonObject json) {

    JsonObject object = new JsonObject();

    SpanLabelView sentenceView = (SpanLabelView) ta.getView(ViewNames.SENTENCE);
    writeString("generator", sentenceView.getViewGenerator(), object);

    writeDouble("score", sentenceView.getScore(), object);
    int numSentences = sentenceView.getNumberOfConstituents();
    int[] sentenceEndPositions = new int[numSentences];

    int id = 0;
    for (Sentence sentence : ta.sentences()) {
      sentenceEndPositions[id++] = sentence.getEndSpan();
    }
    writeIntArray("sentenceEndPositions", sentenceEndPositions, object);

    json.add("sentences", object);
  }