java实现带有抽象方法的枚举

//内部类

public enum TrafficLamp{

  RED(30){

          public TrafficLamp nextLamp(){

              return GREEN;

          }

                  },

 GREEN(45){

          public TrafficLamp nextLamp(){

              return YELLOW;

          }

                  },

 YELLOW(5){

          public TrafficLamp nextLamp(){

              return RED;

          }

                  };

//抽象方法

  public abstract TrafficLamp nextLamp();

  private int time;

  private TrafficLamp(int time){

          this.time=time;

          }

}