Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

Java Java Objects Delivering the MVP Applying a Discount Code

If statement failing to pass while using string matches

Im sure my if statement is wrong but I have been looking at it for hours now and I just can figure it out.

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

 private String normalizeDiscountCode(String discountCode) {
   if (! discountCode.matches("[^A-Za-z]+$")) {
     throw new IllegalArgumentException("Invalid discount code");
   }
   discountCode = discountCode.toUpperCase();
   return discountCode;
 }

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

  public String getItemName() {
    return itemName;
  }

  public int getPriceInCents() {
    return priceInCents;
  }

  public String getDiscountCode() {
    return discountCode;
  }

  public void applyDiscountCode(String discountCode) {
    this.discountCode = normalizeDiscountCode(discountCode);    
  }
}
Example.java
public class Example {

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

    Order order = new Order(
            "Yoda PEZ Dispenser",
            600);

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

    order.applyDiscountCode("$ale");
    order.getDiscountCode(); // $ALE


    try {
      // This will throw an exception because it contains numbers
      order.applyDiscountCode("ABC123");
    } catch (IllegalArgumentException iae) {
      System.out.println(iae.getMessage());  // Prints "Invalid discount code"
    }
    try {
      // This will throw as well, because it contains a symbol.
      order.applyDiscountCode("w@w");
    }catch (IllegalArgumentException iae) {
      System.out.println(iae.getMessage());  // Prints "Invalid discount code"
    }

  }
}

1 Answer

Umesh Ravji
Umesh Ravji
42,386 Points

Hi Reagan, just two small issues, you are calling the match method on a variable that doesn't exist, and your regular expression needs fixing too :)

^[A-Za-z$]+$ looks for anything that is either a alphabetic character or a dollar sign. The ^ must be at the front of the pattern, and not inside the square brackets (where it has a completely different meaning).

private String normalizeDiscountCode(String code) {
  if (!code.matches("^[A-Za-z$]+$")) {  // make sure you are calling the match method on the code variable
     throw new IllegalArgumentException("Invalid discount code");
  }
  return code.toUpperCase(); 
}