1 import java.util.ArrayList;
2
3 /**
4 Describes an invoice for a set of purchased products.
5 */
6 public class Invoice
7 {
8 private Address billingAddress;
9 private ArrayList<LineItem> items;
10
11 /**
12 Constructs an invoice.
13 @param anAddress the billing address
14 */
15 public Invoice(Address anAddress)
16 {
17 items = new ArrayList<LineItem>();
18 billingAddress = anAddress;
19 }
20
21 /**
22 Adds a charge for a product to this invoice.
23 @param aProduct the product that the customer ordered
24 @param quantity the quantity of the product
25 */
26 public void add(Product aProduct, int quantity)
27 {
28 LineItem anItem = new LineItem(aProduct, quantity);
29 items.add(anItem);
30 }
31
32 /**
33 Formats the invoice.
34 @return the formatted invoice
35 */
36 public String format()
37 {
38 String r = " I N V O I C E\n\n"
39 + billingAddress.format()
40 + String.format("\n\n%-30s%8s%5s%8s\n",
41 "Description", "Price", "Qty", "Total");
42
43 for (LineItem item : items)
44 {
45 r = r + item.format() + "\n";
46 }
47
48 r = r + String.format("\nAMOUNT DUE: $%8.2f", getAmountDue());
49
50 return r;
51 }
52
53 /**
54 Computes the total amount due.
55 @return the amount due
56 */
57 private double getAmountDue()
58 {
59 double amountDue = 0;
60 for (LineItem item : items)
61 {
62 amountDue = amountDue + item.getTotalPrice();
63 }
64 return amountDue;
65 }
66 }