尝试理解Java枚举中函数的用法

public enum DayOfWeek {
    MONDAY,
    TUESDAY,
    WEDNESDAY,
    THURSDAY,
    FRIDAY,
    SATURDAY,
    SUNDAY;

    // 普通方法
    public boolean isWeekend() {
        return this == SATURDAY || this == SUNDAY;
    }

    // 抽象方法
    public abstract int getWorkingHours();

    // 枚举常量实现抽象方法
    public enum WorkingDays implements DayOfWeek {
        MONDAY(8),
        TUESDAY(8),
        WEDNESDAY(8),
        THURSDAY(8),
        FRIDAY(8);

        private final int hours;

        WorkingDays(int hours) {
            this.hours = hours;
        }

        @Override
        public int getWorkingHours() {
            return hours;
        }
    }

    public static void main(String[] args) {
        DayOfWeek day = DayOfWeek.MONDAY;
        System.out.println(day.isWeekend()); // 输出: false

        WorkingDays workingDay = WorkingDays.MONDAY;
        System.out.println(workingDay.getWorkingHours()); // 输出: 8
    }
}