code: public static Integer negativeInteger(String value) {
  		Integer intValue = Validate.isInteger(value);
  		negative(intValue);
  		return intValue;
  	}
docs: Checks if the given String is a negative integer value.<br>
  This method tries to parse an integer value and then checks if it is smaller than 0.
  @param value The String value to validate.
  @return The parsed integer value
  @throws ParameterException if the given String value cannot be parsed as integer or its value is bigger or equal to 0.