JAVA

Object Classes: designing Shopping Cart

Shopping Cart , build a checkout system for a shop which sells items (i.e., products say Bread, Milk, and Bananas). A shopping cart that can have multiples. Costs of the products are : Bread - $1, Milk - $0.60 and Banana - $0.40. A system should displays the order total.

The heart of a shopping cart can be represented in three classes: a cart class an order class, and an item class. Item objects are added to an array stored within the cart object.

Object Classes: designing Shopping Cart

Object Classes: designing Shopping Cart

Think first what are the nouns in the specification? (ex: Item) These are likely your Objects or possibly key data in an object

Which responsibilities belong to which nouns? These are likely to become their methods.

What are the relationships between nouns (Objects)? Draw it out that will help you visualize how they are interconnected

Object Classes: designing Shopping Cart

You will find that several Objects have a Has-a relationship An ItemOrder has an Item (one to one relationship) A ShoppingCart has many ItemOrders (one to many relationship)

Object Classes: designing Shopping Cart

Summary Methods with same name, different signatures are overloaded methods An enumeration is a class can have instance variables, constructors, methods A package of class definitions grouped together in same folder, contain a package statement at beginning of each class

Item i double price ItemOrder io 2 int quantity String name 42 "String cheese