private List<String> getTopicTweets(HttpServletRequest request) throws ServletException {

    final String topicFile = request.getParameter("topicFile");
    final String fullFilePath = topicFile;
    List<String> listFiles = new ArrayList<String>();

    Properties properties = new Properties();

    try {
      properties.load(new FileInputStream(fullFilePath));
    } catch (FileNotFoundException e) {
      LOGGER.error("missing file for in topic tweets: '" + fullFilePath + "'" + e.getMessage());
      e.printStackTrace();
    } catch (IOException e) {
      LOGGER.error("can't read file for in topic tweets: '" + fullFilePath + "'" + e.getMessage());
      e.printStackTrace();
    }

    for (Entry<Object, Object> propertyEntry : properties.entrySet()) {
      String key = (String) propertyEntry.getKey();
      if (key.startsWith("inTopic")) {
        listFiles.add((String) propertyEntry.getValue());
      }
    }

    List<String> tweets = new ArrayList<String>();
    for (String filtFile : listFiles) {
      tweets.addAll(parseTweetsFromFile(filtFile));
    }
    return tweets;
  }
  private List<String> getOutOfTopicTweets(HttpServletRequest request) throws ServletException {

    String topicFile = request.getParameter("topicFile");

    List<String> listFiles = new ArrayList<String>();
    Properties properties = new Properties();
    try {
      properties.load(new FileInputStream(topicFile));
    } catch (FileNotFoundException e) {
      final String emsg =
          "missing file for out of topic tweets: '" + topicFile + "'" + e.getMessage();
      LOGGER.error(emsg);
      throw new ServletException(emsg, e);
    } catch (IOException e) {
      final String emsg =
          "can't read file for out of topic tweets: '" + topicFile + "'" + e.getMessage();
      LOGGER.error(emsg);
      throw new ServletException(emsg);
    }

    for (Entry<Object, Object> propertyEntry : properties.entrySet()) {
      String key = (String) propertyEntry.getKey();

      if (key.startsWith("outOfTopic")) {
        listFiles.add((String) propertyEntry.getValue());
      }
    }

    List<String> tweets = new ArrayList<String>();
    for (String filtFile : listFiles) {
      tweets.addAll(parseTweetsFromFile(filtFile));
    }
    return tweets;
  }