Incorrect Code Snippet ?

Question

I think my code is correct but still getting below error:

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

Can someone let me know what I am doing wrong ?

Regards, Sahil

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 = discountCode;
    try{
    this.discountCode = normalizeDiscountCode(discountCode);
    } catch (IllegalArgumentException iae){
     System.out.println(iae.getMessage()); 
    }
  }
  private String normalizeDiscountCode(String discountCode){
   this.discountCode = discountCode.toUpperCase();
    for(char c: this.discountCode.toCharArray()) {
        if (!Character.isLetter(c) && c != '$' ) {
          throw new IllegalArgumentException("Invalid discount code");
        }
    }  
    return this.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"
    }

  }
}

Answer 1 · 2017-05-14T20:06:49Z

May 14, 2017 8:06pm

Hello mate,

Remove every instance of the keyword this found within normalizeDiscountCode(String discountCode). In this context, this.discountCode refers to the member variable with that name and not the method parameter with the same name, resulting in a logical error.
Whilst it's possible to re-assign to the method parameter discountCode, having called toUpperCase() on it, have you considered just calling discountCode.toUpperCase() as part of your return statement?
IllegalArgumentException is an example of what is known as an unchecked exception. Catching it in applyDiscountCode(String discountCode) isn't incorrect, but just know that you don't have to, nor do you have to declare that your method throws such an exception if it isn't handled.

Order.java

public void applyDiscountCode(String discountCode) {
    this.discountCode = discountCode;
    try {    // (3)
        this.discountCode = normalizeDiscountCode(discountCode);    
    } catch (IllegalArgumentException iae){
        System.out.println(iae.getMessage()); 
    }
}

private String normalizeDiscountCode(String discountCode){
   this.discountCode = discountCode.toUpperCase();    // (1)(2)
    for(char c: this.discountCode.toCharArray()) {    // (1)
        if (!Character.isLetter(c) && c != '$' ) {
          throw new IllegalArgumentException("Invalid discount code");
        }
    }  
    return this.discountCode;    // (1)(2)
}

Hope this helps

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Sahil Chawla

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Incorrect Code Snippet ?

1 Answer

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Sahil Chawla

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