code: private Integer getNullOnValue(Integer value, int nullValue)
     {
        return (NumberHelper.getInt(value) == nullValue ? null : value);
     }
docs: This method returns the value it is passed, or null if the value
  matches the nullValue argument.
  
  @param value value under test
  @param nullValue return null if value under test matches this value
  @return value or null