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Java Java Objects Delivering the MVP Applying a Discount Code

Enyang Mercy
PLUS
Enyang Mercy
Courses Plus Student 2,339 Points
Posted by Enyang Mercy
Enyang Mercy
Courses Plus Student 2,339 Points

Help!! Validation skills Throw an exception

i keep having compiler errors. Can't really figure it out

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) {
    if (! Chraracter.isLetter(letter)) {
      throw new IllegalArgumentException("Invalid Discount Code");
    }
    return discountCode.toUpperCase();
}
}
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"
    }

  }
}
Zac Mazza
Zac Mazza
5,867 Points
Zac Mazza
Zac Mazza
5,867 Points

Hey there, I've looked over your code, and without seeing the compilation error nothing is standing out. 

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

I'm curious in the code above if: 

this.discountCode = normalizeDiscountCode(discountCode);

should be:

this.discountCode = this.normalizeDiscountCode(discountCode);

Could the compilation error be occurring as normalizeDiscountCode(discountCode) is being called from a static context (such as shown in the first example)?

If you don't mind, please share the specific error you are receiving and I'd be more than happy to help you troubleshoot and debug. :-)

Good luck!

Zac Mazza
Zac Mazza
5,867 Points
Zac Mazza
Zac Mazza
5,867 Points

Did some additional checking... this may help. Character.isLetter(letter) only applies to single Characters. The 'letter' parameter is also not being passed, rather, discountCode is.

Two things need to be done to get this code to compile. A different solution is needed for checking if symbols or numbers appear:

  private String normalizeDiscountCode(String discountCode) {
    if (!discountCode.matches("[a-zA-Z$]+")) {
      throw new IllegalArgumentException("Invalid Discount Code");
    }
    return discountCode.toUpperCase();
}

The above code will check to see if the discount code matches certain letters or a $. If it does not, a boolean value is returned and the code continues as you have it written. This compares the entire string, whereas the current code looks for a Character, but receives a String.

Changing (! Character.isLetter(letter) to (!discountCode.matches("[a-zA-Z]+")) will solve the issue.

Hope this helps!

Zac

Mehdi Amir
Mehdi Amir
434 Points
Mehdi Amir
Mehdi Amir
434 Points

private String normalizeDiscountCode(String discountCode) { if (! Chraracter.isLetter(letter)) {

<<<<<<<<<<<<<<<<<<<<<<<<<<< You misspelled Character.isLetter

  throw new IllegalArgumentException("Invalid Discount Code");
}
return discountCode.toUpperCase();