@Override
  public void setSettings(Settings settings) {
    this.settings = settings;

    String paramString = settings.getUpdateScriptParams();
    List<String> fields = StringUtils.tokenize(paramString);
    for (String string : fields) {
      List<String> param = StringUtils.tokenize(string, ":");
      Assert.isTrue(param.size() == 2, "Invalid param definition " + string);

      params.put(param.get(0), createFieldExtractor(param.get(1)));
    }
  }