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Java Java Objects Delivering the MVP Applying a Discount Code

Posted by Arthur Kharzamanov
Arthur Kharzamanov
5,414 Points

Oops! It looks like Task 1 is no longer passing. Don't know how do get around that:(

Task: In the normalizeDiscountCode verify that only letters or the $ character are used. If any other character is used, throw a IllegalArgumentException with the message Invalid discount code.

I added an enhanced for loop to check for illicit characters in every char in the discountCode. If all pass then I set discountCode to all upperCase otherwise throw an exception. I catch the exception in the method below and in case of no exception the field discountCode should be set to normalizeDiscountCode. I can't seem to find my mistake:(((

Order.java 
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;
  }

  public String getDiscountCode() {
    return discountCode;
  }

  private String normalizeDiscountCode (String discountCode) {
    for (char letter : discountCode.toCharArray()) {
      if (!Character.isLetter(letter) || letter != '$') {
         throw new IllegalArgumentException("Invalid discount code.");
      }
    }
    return discountCode.toUpperCase();
  }

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

  }
}

5 Answers

markmneimneh
markmneimneh
14,132 Points
markmneimneh
markmneimneh
14,132 Points

Hi

I believe the problem is here

if (!Character.isLetter(letter) || letter != '$') { throw new IllegalArgumentException("Invalid discount code."); }

Try && instead of II

if (!Character.isLetter(letter) && letter != '$') { throw new IllegalArgumentException("Invalid discount code."); }

If this answers your question, please mark the quation as answered.

You could try other options as well .. but the bottom line is that

!Character.isLetter(letter) || letter != '$'

is probably not what you mean to check.

Thanks

Craig Dennis
STAFF
Craig Dennis
Treehouse Teacher
Craig Dennis
Craig Dennis
Treehouse Teacher

Ha! Sorry...don't catch it, I'm looking for it in my test ;) Sorry for the confusion, will update the instructions.

Arthur Kharzamanov
Arthur Kharzamanov
5,414 Points
Arthur Kharzamanov
Arthur Kharzamanov
5,414 Points

That's true, thank you! However, once I changed it the challenge shows an error: Hmmm...I ran order.applyDiscountCode("h1!") and I expected it to throw an IllegalArgumentException, but it didn't.

It should have thrown an exception since 1 is not a letter AND is not '$'.

Any thoughts?

markmneimneh
markmneimneh
14,132 Points
markmneimneh
markmneimneh
14,132 Points

I tested your code ... it fails for this string "h1!"

make this minor change (I added + discountCode)

public void applyDiscountCode(String discountCode) {
    try {
        this.discountCode = normalizeDiscountCode(discountCode);
    } catch (IllegalArgumentException iae) {
        System.out.println(iae.getMessage() + discountCode);
    }
}

This is what I am getting

Invalid discount code.ABC123 Invalid discount code.w@w Invalid discount code.h1!

Process finished with exit code 0

Arthur Kharzamanov
Arthur Kharzamanov
5,414 Points

So it does throw and catch the exception! By adding "+ discountCode" it just prints what the invalid discount code indeed was. Why won't the challenge accept this code then?

Arthur Kharzamanov
Arthur Kharzamanov
5,414 Points
Arthur Kharzamanov
Arthur Kharzamanov
5,414 Points

Bummer! Hmmm...I ran order.applyDiscountCode("h1!") and I expected it to throw an IllegalArgumentException, but it didn't.

The preview even shows the exception: Invalid discount code. So is that a bug on treehouse side? Or I'm just really confused now...