private Fields generateTermVectorsFromDoc(TermVectorRequest request, boolean doAllFields)
      throws IOException {
    // parse the document, at the moment we do update the mapping, just like percolate
    ParsedDocument parsedDocument =
        parseDocument(indexShard.shardId().getIndex(), request.type(), request.doc());

    // select the right fields and generate term vectors
    ParseContext.Document doc = parsedDocument.rootDoc();
    Collection<String> seenFields = new HashSet<>();
    Collection<GetField> getFields = new HashSet<>();
    for (IndexableField field : doc.getFields()) {
      FieldMapper fieldMapper = indexShard.mapperService().smartNameFieldMapper(field.name());
      if (seenFields.contains(field.name())) {
        continue;
      } else {
        seenFields.add(field.name());
      }
      if (!isValidField(fieldMapper)) {
        continue;
      }
      if (request.selectedFields() == null
          && !doAllFields
          && !fieldMapper.fieldType().storeTermVectors()) {
        continue;
      }
      if (request.selectedFields() != null && !request.selectedFields().contains(field.name())) {
        continue;
      }
      String[] values = doc.getValues(field.name());
      getFields.add(new GetField(field.name(), Arrays.asList((Object[]) values)));
    }
    return generateTermVectors(getFields, request.offsets(), request.perFieldAnalyzer());
  }
 /** populates a request object (pre-populated with defaults) based on a parser. */
 public static void parseRequest(TermVectorRequest termVectorRequest, XContentParser parser)
     throws IOException {
   XContentParser.Token token;
   String currentFieldName = null;
   List<String> fields = new ArrayList<>();
   while ((token = parser.nextToken()) != XContentParser.Token.END_OBJECT) {
     if (token == XContentParser.Token.FIELD_NAME) {
       currentFieldName = parser.currentName();
     } else if (currentFieldName != null) {
       if (currentFieldName.equals("fields")) {
         if (token == XContentParser.Token.START_ARRAY) {
           while (parser.nextToken() != XContentParser.Token.END_ARRAY) {
             fields.add(parser.text());
           }
         } else {
           throw new ElasticsearchParseException(
               "The parameter fields must be given as an array! Use syntax : \"fields\" : [\"field1\", \"field2\",...]");
         }
       } else if (currentFieldName.equals("offsets")) {
         termVectorRequest.offsets(parser.booleanValue());
       } else if (currentFieldName.equals("positions")) {
         termVectorRequest.positions(parser.booleanValue());
       } else if (currentFieldName.equals("payloads")) {
         termVectorRequest.payloads(parser.booleanValue());
       } else if (currentFieldName.equals("term_statistics")
           || currentFieldName.equals("termStatistics")) {
         termVectorRequest.termStatistics(parser.booleanValue());
       } else if (currentFieldName.equals("field_statistics")
           || currentFieldName.equals("fieldStatistics")) {
         termVectorRequest.fieldStatistics(parser.booleanValue());
       } else if ("_index"
           .equals(currentFieldName)) { // the following is important for multi request parsing.
         termVectorRequest.index = parser.text();
       } else if ("_type".equals(currentFieldName)) {
         termVectorRequest.type = parser.text();
       } else if ("_id".equals(currentFieldName)) {
         if (termVectorRequest.doc != null) {
           throw new ElasticsearchParseException(
               "Either \"id\" or \"doc\" can be specified, but not both!");
         }
         termVectorRequest.id = parser.text();
       } else if ("doc".equals(currentFieldName)) {
         if (termVectorRequest.id != null) {
           throw new ElasticsearchParseException(
               "Either \"id\" or \"doc\" can be specified, but not both!");
         }
         termVectorRequest.doc(jsonBuilder().copyCurrentStructure(parser));
       } else if ("_routing".equals(currentFieldName) || "routing".equals(currentFieldName)) {
         termVectorRequest.routing = parser.text();
       } else {
         throw new ElasticsearchParseException(
             "The parameter " + currentFieldName + " is not valid for term vector request!");
       }
     }
   }
   if (fields.size() > 0) {
     String[] fieldsAsArray = new String[fields.size()];
     termVectorRequest.selectedFields(fields.toArray(fieldsAsArray));
   }
 }
  private Fields addGeneratedTermVectors(
      Engine.GetResult get,
      Fields termVectorsByField,
      TermVectorRequest request,
      Set<String> selectedFields)
      throws IOException {
    /* only keep valid fields */
    Set<String> validFields = new HashSet<>();
    for (String field : selectedFields) {
      FieldMapper fieldMapper = indexShard.mapperService().smartNameFieldMapper(field);
      if (!isValidField(fieldMapper)) {
        continue;
      }
      // already retrieved, only if the analyzer hasn't been overridden at the field
      if (fieldMapper.fieldType().storeTermVectors()
          && (request.perFieldAnalyzer() == null
              || !request.perFieldAnalyzer().containsKey(field))) {
        continue;
      }
      validFields.add(field);
    }

    if (validFields.isEmpty()) {
      return termVectorsByField;
    }

    /* generate term vectors from fetched document fields */
    GetResult getResult =
        indexShard
            .getService()
            .get(
                get,
                request.id(),
                request.type(),
                validFields.toArray(Strings.EMPTY_ARRAY),
                null,
                false);
    Fields generatedTermVectors =
        generateTermVectors(
            getResult.getFields().values(), request.offsets(), request.perFieldAnalyzer());

    /* merge with existing Fields */
    if (termVectorsByField == null) {
      return generatedTermVectors;
    } else {
      return mergeFields(termVectorsByField, generatedTermVectors);
    }
  }