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Java Java Objects Delivering the MVP Applying a Discount Code

I dont understand why this isnt working. contains only letters || '$'

(string.matches("^[a-zA-Z0-9_]+$")) { was suggested but im not sure if thats what its trying to teach. im assuming the question and my code will show up so its self explanatory on what im struggling with.

public class Order {
  private String itemName;
  private int priceInCents;
  private String discountCode;

  public Order(String itemName, int priceInCents) {
    this.itemName = itemName;
    this.priceInCents = priceInCents;

  public String getItemName() {
    return itemName;

  public int getPriceInCents() {
    return priceInCents;

  private String normalizeDiscountCode(String code) {
    if(! code.matches("[abcdefghijklmnopqrstuvwxyz$]")) {
      throw new IllegalArgumentException("Please enter a valid entry with letters or $ only");
    String upperCaseCode = code.toUpperCase();
    return upperCaseCode;

  public String getDiscountCode() {
    return discountCode;

  public void applyDiscountCode(String discountCode) {
    String buffer = "";
  try {
  buffer = normalizeDiscountCode(discountCode);
} catch (IllegalArgumentException iae)  { System.out.printf(iae.getMessage()); }
      this.discountCode = buffer;
public class Example {

  public static void main(String[] args) {
    // This is here just for example use cases.

    Order order = new Order(
            "Yoda PEZ Dispenser",

    // These are valid.  They are letters and the $ character only
    order.getDiscountCode(); // ABC

    order.getDiscountCode(); // $ALE

    try {
      // This will throw an exception because it contains numbers
    } catch (IllegalArgumentException iae) {
      System.out.println(iae.getMessage());  // Prints "Invalid discount code"
    try {
      // This will throw as well, because it contains a symbol.
    }catch (IllegalArgumentException iae) {
      System.out.println(iae.getMessage());  // Prints "Invalid discount code"


1 Answer

closed. I figured it out. i put the try in when i didnt know the example already held it. also, i used .matches("[a-zA-Z$]*")