public class MailSystem
1: import java.util.ArrayList;
3: /**
4: A system of voice mail boxes.
5: */
6: public class MailSystem
7: {
8: /**
9: Constructs a mail system with a given number of mail boxes
10: @param mailboxCount the number of mailboxes
11: */
12: public MailSystem(int mailboxCount)
13: {
14: mailboxes = new ArrayList<Mailbox>(mailboxCount);
16: /*
17: Initialize mail boxes.
18: */
19: for (int i = 0; i < mailboxCount; i++)
20: {
21: String passcode = "" + (i + 1);
22: String greeting = "You have reached mailbox " + (i + 1)
23: + ". \nPlease leave a message now.";
24: mailboxes.add(i, new Mailbox(passcode, greeting));
25: }
26: }
28: /**
29: Locate a mailbox.
30: @param ext the extension number
31: @return the mailbox or null if not found
32: */
33: public Mailbox findMailbox(String ext)
34: {
35: int i = Integer.parseInt(ext);
36: if (1 <= i && i <= mailboxes.size())
37: return mailboxes.get(i - 1);
38: else return null;
39: }
41: private ArrayList<Mailbox> mailboxes;
42: }