Listing3: CreditCard Class
public class CreditCard {
String cardType;
String cardNumber;
String cardExpDate;
final String CC_DATA_FILE = "CC.txt";
public CreditCard(String ccType, String ccNumber,
String ccExpDate) {
cardType = ccType;
cardNumber = ccNumber;
cardExpDate = ccExpDate;
}
public boolean isValid() {
/*
Let's go with simpler validation
here to keep the example simpler.
*/
if (getCardType().equals(AccountManager.VISA)) {
return (getCardNumber().trim().length() == 16);
}
if (getCardType().equals(AccountManager.DISCOVER)) {
return (getCardNumber().trim().length() == 15);
}
if (getCardType().equals(AccountManager.MASTER)) {
return (getCardNumber().trim().length() == 16);
}
return false;
}
public boolean save() {
FileUtil futil = new FileUtil();
String dataLine = getCardType() + ,”" + getCardNumber() + ”," + getCardExpDate();
return futil.writeToFile(CC_DATA_FILE, dataLine, true, true);
}
public String getCardType() {
return cardType;
}
public String getCardNumber() {
return cardNumber;
}
public String getCardExpDate() {
return cardExpDate;
}
}
Figure3: Subsystem Classes to Provide the Necessary Functionality to Validate and Save the Customer Data
