枚举enum的简单实例

public abstract class WeekDay1 {

    private WeekDay1(){}
    
    public final static WeekDay1 SUN = new WeekDay1() {
        //抽象类的方法不能实现，所以只能用内部子类实现
        @Override
        public WeekDay1 nextDay() {
            // TODO Auto-generated method stub
            return MON;
        }
        
    };
    
    public final static WeekDay1 MON = new WeekDay1() {

        @Override
        public WeekDay1 nextDay() {
            // TODO Auto-generated method stub
            return SUN;
        }
        
    };
    
    public abstract WeekDay1 nextDay();
    
    /***
     * 
     * @author Administrator
        枚举 周一  到  周日  及带参数的构造方法
     */
    public enum WeekDay{
        SUN(1),MON(),TUE(1,2,3,4),WED,THI,FRI,SAT;
        private WeekDay(){System.out.println("first");}
        private WeekDay(int day){System.out.println("second");}
        private WeekDay(int day,int ... args){
            System.out.println("thired");
        }
    }
    
    public static void main(String[] args) {
        System.out.println(WeekDay.SUN);
    }
    
    
    /***
     * 枚举红绿黄灯
     */
    public enum TrafficLamp{
        RED(30) {
            @Override
            public TrafficLamp nextLamp() {
                // TODO Auto-generated method stub
                return GREEN;
            }
        } ,
        GREEN(40) {
            @Override
            public TrafficLamp nextLamp() {
                // TODO Auto-generated method stub
                return YELLOW;
            }
        },
        YELLOW(5) {
            @Override
            public TrafficLamp nextLamp() {
                // TODO Auto-generated method stub
                return RED;
            }
        };
        public abstract TrafficLamp nextLamp();
        private int time;
        private TrafficLamp(){}
        private TrafficLamp(int time){
            this.time = time;
        }
    }
}