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Java Java Objects Delivering the MVP Applying a Discount Code

Matthew Dorber
Matthew Dorber
752 Points
Posted by Matthew Dorber
Matthew Dorber
752 Points

Still struggling :(

I don't understand what's wrong with this?

If it's not a letter AND it's not a dollar sign - throw an exception.

So how is it not throwing an exception for 'h1!' ?

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;
  }

  private String normalizeDiscountCode(String discountCode)
  {
    for (char code : discountCode.toCharArray())
    {
    if ((!Character.isLetter(code)) && (discountCode.indexOf('$') == -1))
    throw new IllegalArgumentException("Invalid discount code.");   
    }
    return discountCode.toUpperCase(); 
}
  public int getPriceInCents() {
    return priceInCents;
  }

  public String getDiscountCode() {
    return discountCode;
  }

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

andren
andren
28,558 Points
andren
andren
28,558 Points

Your code is quite close, but there are two issues:

  1. You should not be using the indexOf method to check for '$' but should just compare the code to it directly like this: code != '$'. Otherwise your code will fail when it encounters a discount code featuring the '$' character.

  2. Your code does in fact raise an exception for 'h1!', the issue is that your code also catches that exception, which means that the challenge checker which runs your code does not get any indication that an exception occurred.

If you change how you deal with the $ character and remove the code that catches the exception, like this:

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;
  }

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

  public String getDiscountCode() {
    return discountCode;
  }

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

Then your code will work.

Matthew Dorber
Matthew Dorber
752 Points
Matthew Dorber
Matthew Dorber
752 Points

Thanks Andren! I can finally move forward with this.