java枚举类

public enum TrafficLamp
{
    //红灯
    RED(30) {
        @Override
        public TrafficLamp nextLamp() {
            return GREEN;
        }
    //绿灯
    },GREEN(40) {
        @Override
        public TrafficLamp nextLamp() {
            return YELLOW;
        }
    //黄灯
    },YELLOW(5) {
        @Override
        public TrafficLamp nextLamp() {
            return RED;
        }
    };
    
    //抽象方法，下一个交通灯
    public abstract TrafficLamp nextLamp();
    
    //等待时间
    private int time;
    
    //构造方法
    private TrafficLamp(int time)
    {
        this.time = time;
    }
}