E-Commerce Application in Java

The Product Class The Product class will store information about items being sold by the store. A Product object must only have a (1) name, (2) id, and (3) price. It does not have any other fields. The information in these fields should be retrievable but cannot be changed once the Product object is created. The Inventory Class The Inventory class will track the state of the inventory of your system. It should keep track of the type and quantity of each Product, as well as provide methods to access and modify this information. The following functionalities should be available in any given Inventory object:

- Get the amount of stock for a given Product ID (Note: it is possible the Product does not exist in the Inventory!). - Add a specified amount of stock for a given Product to the inventory (Note: new Products can be added!).

- Remove a specified amount of stock for a given Product ID from the inventory (Note: you cannot have negative stock, and you cannot delete Products from the Inventory; if a Products stock reaches 0, leave it.). - Get information on a Product given a Product ID.

- Initialize the Inventory; set the contents of the Inventory to some default values upon object creation. The StoreManager Class StoreManager is the brain of the system. It contains all the functionality for managing the Inventory, ShoppingCarts, and providing information to the StoreView class. StoreManager manages a single Inventory and it will have a variety of methods two for now- to interact with this Inventory object. A StoreManager object should:

- Create a new Inventory object upon object creation (i.e., when a StoreManager object is created).

- Have functionality to check how much stock of a given Product is in the Inventory. - Have functionality to process a transaction given an Array of Product information. For example, imagine that the content of a users shopping cart is as follows: [[productID1, quantity], [productID2, quantity], [productID3, quantity]]. Given each productID, your method should:

o Check that the desired quantity exists in the Inventory and return the total for all of the Products

. o If there is insufficient quantity of any of the products, your method should return some indication of this failure. It could be, for example -1.

o Remember to subtract the quantities from the Inventory stock if the transaction is successful.

e UML class diagram of the current state of the system