Suppose a class GroceryBill
keeps track of a list of items being purchased at a market:
Method/Constructor |
Description |
public GroceryBill(Employee clerk) |
constructs a GroceryBill object for the given clerk |
public void add(Item i) |
adds i to this bill's total |
public double getTotal() |
returns the cost of these items |
public void printReceipt() |
prints a list of items |
GroceryBill
objects interact with Item
objects. An Item
has the following public methods:
Method/Constructor |
Description |
public double getPrice() |
returns the price for this item |
public double getDiscount() |
returns the discount for this item |
For example, a candy bar item might cost 1.35
with a discount of 0.25
for preferred customers, meaning that preferred customers get it for 1.10
. (Some items will have no discount, 0.0
.) Currently the above classes do not consider discounts. Every item in a bill is charged full price, and item discounts are ignored.
Define a class DiscountBill
that extends GroceryBill
to compute discounts for preferred customers. The constructor for DiscountBill
accepts a parameter for whether the customer should get the discount.
Your class should adjust the amount reported by getTotal
for preferred customers. For example, if the total would have been $80
but a preferred customer is getting $20
in discounts, then getTotal
should report the total as $60
for that customer. You should also keep track of how many items a customer is getting a non-zero discount for and the overall discount, both as a total amount and as a percentage of the original bill. Include the extra methods below that allow a client to ask about the discount:
Method/Constructor |
Description |
public DiscountBill(Employee clerk, boolean preferred) |
constructs bill for given clerk |
public int getDiscountCount() |
returns the number of items that were discounted, if any |
public double getDiscountAmount() |
returns the total discount for this list of items, if any |
public double getDiscountPercent() |
returns the percent of the total discount as a percent of what the total would have been otherwise |
If the customer is not a preferred customer the DiscountBill
behaves at all times as if there is a total discount of 0.0 and no items have been discounted.