import java.util.Date;

public class CreditCard {
    private String cardNumber;
    private Date expiryDate;

    public CreditCard(String cardNumber, Date expiryDate) {
        // Not a complete date
        this.cardNumber = cardNumber;
        this.expiryDate = expiryDate;
    }

    public boolean isExpired() {
        Date currentDate = new Date();
        return expiryDate.before(currentDate);
        // How will it work? 
        // using the last day of the month?
    }
}

public class CreditCard {
    private String cardNumber;
    private int expiryMonth;
    private int expiryYear;

    public CreditCard(String cardNumber, int expiryMonth, int expiryYear) {
        this.cardNumber = cardNumber;
        this.expiryMonth = expiryMonth;
        this.expiryYear = expiryYear;
        // No validations on number ranges?
    }

    public boolean isExpired(int currentMonth, int currentYear) {
        return (expiryYear < currentYear) ||
            (expiryYear == currentYear && expiryMonth < currentMonth);
    }
    // Inappropriate intimacy code smell

}

class CreditCard {
  private String number;
  private MonthOfYear expiryDate;
  // expiryDate is the role
  // MonthOfYear is the type
}

class MonthOfYear {
  private Month month;  
  private Year year;
  // These are other small objects

  public MonthOfYear(Month month, Year year) {
    // You don't need to add validations since 
    // month is a valid month
    // year is a valid year
    this.month = month;
    this.year = year;
  } 

  public boolean isBeforeEndOfMonth(Date date) {
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(date);
    return (calendar.get(Calendar.YEAR) < year.value()) ||
           (calendar.get(Calendar.YEAR) == year.value() &&
            calendar.get(Calendar.MONTH) < month.value())      
    // Notice there are no days involved   
  }

  // This protocol is just for MonthOfYears  
  public Day[] getDaysInMonth() { }

  public boolean isLeapYear() { } // ...

  public void iterateDays() { } // ...

}