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Java Java Objects Delivering the MVP Applying a Discount Code

Arne Stops
Arne Stops
642 Points

Problems with If condition

Pretty much the title...

I don´t know how to get the condition right

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) {
    if (!discountCode.matches("[a-zA-Z]") == true | !discountCode.matches("$") == true) {
      throw new IllegalArgumentException ("Invalid discount code");
    }
    this.discountCode = discountCode.toUpperCase();
    return discountCode;
  }

  public int getPriceInCents() {
    return priceInCents;
  }

  public String getDiscountCode() {
    return discountCode;
  }

  public void applyDiscountCode(String discountCode) {
    discountCode = normalizeDiscountCode(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"
    }

  }
}

1 Answer

Florian Tönjes
seal-mask
.a{fill-rule:evenodd;}techdegree seal-36
Florian Tönjes
Full Stack JavaScript Techdegree Graduate 50,856 Points

Hi Arne,

nice try. One can solve this using the toCharArray() method of the String class and looping over all the characters and check if they are allowed or not.

You approached this trying to use regular expressions, props for that. And you almost got it right.

    if (!discountCode.matches("[a-zA-Z$]+")) {
      throw new IllegalArgumentException ("Invalid discount code");
    }

You need the "+" to check for more than one character. You can also put the dollar sign into the character range. You can find more infos here.

Kind Regards, Florian