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Java Java Objects (Retired) Delivering the MVP Defaulting Parameters

Kenneth Balajadia
Kenneth Balajadia
2,009 Points

So at your new Java job, you've written a brand new Shopping Cart system for the website. After some developers have use

im lost ! So at your new Java job, you've written a brand new Shopping Cart system for the website. After some developers have used the objects you created for a while, they ask you to make it easier to add things to the cart.

Check out more instructions in Example.java. Once you implement their request, check your work, and you will pass the challenge.

Example.java
public class Example {

  public static void main(String[] args) {
    ShoppingCart cart = new ShoppingCart();
    Product pez = new Product("Cherry PEZ refill (12 pieces)");
    cart.addItem(pez, 5);
    /* Since a quantity of 1 is such a common argument when adding a product to the cart,
     * your fellow developers have asked you to make the following code work, as well as keeping
     * the ability to add a product and a quantity.
     */

    Product dispenser = new Product("Yoda PEZ dispenser");
    /* Uncomment the line following this comment,
       after adding a new method using method signatures,
       to solve their request in ShoppingCart.java
    */
    // cart.addItem(dispenser);
  }

}
ShoppingCart.java
public class ShoppingCart {

  public void addItem(Product item, int quantity) {
    System.out.printf("Adding %d of %s to the cart.%n", quantity, item.getName());
    /* Other code omitted for clarity. Please imagine
       lots and lots of code here. Don't repeat it. 
    */
  }
}
Product.java
public class Product {
  /* Other code omitted for clarity, but you could imagine
     it would store price, options like size and color
  */
  private String mName;

  public Product(String name) {
      mName = name;
  }

  public String getName() {
      return mName;
  }
}

2 Answers

Grigorij Schleifer
Grigorij Schleifer
10,365 Points

Hi Kenneth,

here you will need a new method inside the Example class, that is called the same as an existing one, addItem().

Like this:

public void addItem(Product item) {
    addItem(item, 1);
 }

The two addItem() methods are not the same, they have different method signatures (different number of parameters). First addItem method takes product and quantity, your new addItem takes only a product.

If you uncomment this line you will see that you are using your new addItem method that takes only one parameter "dispenser"-Product.

cart.addItem(dispenser); // uncommented

Inside the new addItem method, we call the "old" addItem method and set the quantity to 1 product. So when you are calling addItem and add only one product, you are adding only one dispenser to the shopping cart.

Does it make sense?

Grigorij