Using Collections and Strings in a Reusable Class - Java Programming: Comprehensive Concepts and Techniques - page 547

Table 9-3 Class and Instance Variables of the Password Class
VARIABLE SCOPE

DATA TYPE VARIABLE NAME PURPOSE

Class int (final) MIN_SIZE Indicates the minimum size

(length) of a password

Class int (final) MAX_SIZE Indicates the maximum size

(length) of a password

Class int maxHistory Indicates the maximum

number of entries in
password history list

Class int expiresNotifyLimit Indicates the number of

remaining uses when
password nears expiration

Instance int maxUses Indicates the maximum

number of uses for an auto-
expiring password

Instance int remainingUses Indicates the number of

remaining uses for an auto-
expiring password

Instance boolean autoExpires Indicates whether password

should automatically expire

Instance boolean expired Indicates whether password

has expired

Instance ArrayList pswdHistory Contains a list of current and

recently used passwords

The following steps enter the code to declare class and instance variables,
including the final variables, for the Password class.

1 /*
2 Chapter 9: The Password Class

3 Programmer: Michael Mick

4 Date: November 28, 2007

5 Filename: Password.java

6 Purpose: To provide a reusable Password class

7 */
8
9 import java.util.*;
10
11 public class Password
12 {
13 final static int MIN_SIZE = 6;

14 final static int MAX_SIZE = 15;

15 static int maxHistory = 4;

16 static int expiresNotifyLimit = 3;

17
18 private int maxUses = 120;

19 private int remainingUses = maxUses;

20 private boolean autoExpires = true ;

21 private boolean expired = false ;

22
23 private ArrayList pswdHistory;

24

FIGURE 9-5