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Java Java Objects (Retired) Delivering the MVP Defaulting Parameters

help with exercise needed

can't solve this one, can't even understand what is asked for me, pls help :(

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;
  }
}

1 Answer

Hey Martins,

This question is meant to help you learn method signatures. As you can see, the method addItem takes a product and a quantity. What you are asked to do is make a new addItem method that will take only a product and automatically set the quantity to one, since this is such a common quantity. To do this, you need to understand method signatures, where you can create different versions of the same function (function overloading if you're familiar with C++) that takes different parameters.

One thing you want to do when using method signatures is try to rewrite as little code as possible (remember DRY, Don't Repeat Yourself). Thus, you can make an addItem method that doesn't take a quantity, and calls the addItem method already written with a different signature, which requires a quantity input.

Think about this and give it a shot!