JDK5新特性_2.模拟枚举类型

/**
 * 模拟枚举
 * 
 * @author Administrator
 *
 */
public abstract class T3_WeekDay {
    /**
     * 私有化构造器，防止用户创建对象
     */
    private T3_WeekDay() {
    }

    // 创建两个“枚举”对象
    public static final T3_WeekDay SUN = new T3_WeekDay() {
        /**
         * 用匿名内部类去重写nextDay方法，将if，else，转移成了一个个独立的类
         */
        @Override
        public T3_WeekDay nextDay() {
            return MON;
        }

        public String toString() {
            return "MON";
        };

    };

    public static final T3_WeekDay MON = new T3_WeekDay() {

        @Override
        public T3_WeekDay nextDay() {
            return SUN;
        }

        public String toString() {
            return "SUN";
        };

    };

    public abstract T3_WeekDay nextDay();
}