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Java Java Objects Delivering the MVP Applying a Discount Code

how can i create a new private method named normalizeDiscountCode that accepts a String and returns a String and on how?

help me please

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;
  }
  private char normalizeDiscountCode (String discountCode) {
    discountCode = Character.toUpperCase(discountCode);
  return 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"
    }

  }
}

2 Answers

Marvin Deutz
Marvin Deutz
8,349 Points

Well the syntax for your described method would be :

private String normalizeDiscountCode(String code) {
  //Do your method here
  return desiredString;
}

But to properly be able to help you, you need to be a bit more precise.

Marvin Deutz
Marvin Deutz
8,349 Points

Ah I just now see that you already have a method. Well as you are saying your self

  private char normalizeDiscountCode (String discountCode) {
    discountCode = Character.toUpperCase(discountCode);
  return discountCode;
  }

You want to return a String so your method should represent that. And because the discountCode you enter in the method is a String and not char you don't need a helper class. You can just use the .toUpperCase method on it. The rest you probably can figure out on your own ;) If not just write again and I can supply you with the answer and explain it to you in more detail.