Class Cart

java.lang.Object
  |
  +--Cart

public class Cart

extends java.lang.Object

Invariant: For each item, quantity in cart plus quantity recorded in database equals total current inventory. This is a single thread class. Only one of the public functions may be active at a time.

Since:

0.0

Constructor Summary

Cart(Customer c)
Creates an empty cart for customer c.

Method Summary

boolean	addToCart(java.lang.Object item, int quantity)
Enumeration	contents() Returns a sequence of the cart's contents.
void	removeFromCart(java.lang.Object item) If any quantity of the item is in the cart, it is removed and returned to the main DB.
int	totalPrice()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

Cart

public Cart(Customer c)

Creates an empty cart for customer c.

Parameters:

c - (if customer objects have states in which carts cannot be created for them, I would assert the precondition for an acceptable state here. The reason for having the customer at all is just to filter out demands for too many copies of an item.)

See Also:

Customer

Method Detail

contents

public Enumeration contents()

Returns a sequence of the cart's contents.

Returns:

an enumeration object for traversing the entire cart contents in alphabetical order by title.

addToCart

public boolean addToCart(java.lang.Object item,
                         int quantity)

Parameters:

quantity - This must be positive and below the customer's per item limit.

item - The item must be on our current stock list.

Returns:

True iff current available inventory of item is no less than quantity.

The specified quantity of item is removed from the central DB and added to this cart.

removeFromCart

public void removeFromCart(java.lang.Object item)

If any quantity of the item is in the cart, it is removed and returned to the main DB.

totalPrice

public int totalPrice()

Returns:

The sum of the prices of all of the items in the cart.