code: public Integer getStep() {
      if (StringUtils.isEmpty(getInputElement().getStep())) {
        return null;
      }
      try {
        return Integer.valueOf(getInputElement().getStep());
      } catch (final NumberFormatException e) {
        return null;
      }
    }
docs: get distance value should be increased/decreased when using up/down buttons.
  
  @return maximum value allowed