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Java Java Objects Delivering the MVP Applying a Discount Code

Yves Le Palud
Yves Le Palud
4,894 Points

Stuck in Normalize a discount code part 2

Could you look at my normalizeDiscountCode I don't understand why it doesn't work. When I click on check work, it said that task 1 isn't working anymore.

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;
  }

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

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

  }
}

2 Answers

Yanuar Prakoso
Yanuar Prakoso
15,196 Points

Hi Yves....

If your problem is Task one no longer works it means the main problem in in the IF STATEMENT. Well The challenge stated IF it is not a letter or character '$' throw IllegalArgumentException meaning you should write it as:

IF NOT(is a letter OR character '$') then throw IllegalArgumentException

IF !(is a letter || character '$') then throw IllegalArgumentException

Meanwhile you wrote in your code:

IF(!(is a letter) || (Character != '$')) then throw IllegalArgumentException <-- this is wrong. If you insist to use this kind of structure you should write it as:

IF(!(is a letter) && (Character !='$')) then throw IllegalArgumentException

And also may I suggest cleaner code writing (This is just a suggestion). It will help other developer to read your code easier:

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

  private String normalizeDiscountCode(String discountCode) {
    for (char character : discountCode.toCharArray()) {
      if (!(Character.isLetter(character)) && (character != '$')) {
        throw new IllegalArgumentException("Invalid discount code.");
      }//you only need to validate you do not need to transform the characters to upper case one by one
    }
//you can just tell java to make all letters upper case, non alphabetic caharacters (such as '$') will be left alone 
//in their original state.
    return discountCode.toUpperCase();
  }

Please note that I use and modify your style of IF statement. I hope this can help

Yves Le Palud
Yves Le Palud
4,894 Points

Thank you it's working!

I have to make simplier logical expression, I guess?

I try things before submit my problem that why my code wasn't clean. It's good to show how to clean code.