public class Test {

     public static void main(String[] args) {
         Trafficlight light = Trafficlight.RED;

         System.out.println(light.time);
         System.out.println(light.nextLigth());
         // ordinal()方法返回枚舉聲明的順序
         System.out.println(light.ordinal());
         // values()方法得到所有枚舉類型的一個數組
         for(Trafficlight light1:light.values()){
             System.out.println(light1.name());
         }

         // valueOf()方法可以把字符串轉換成相應的枚舉對象
         System.out.println(light.RED ==light.valueOf("RED"));
     }

     public enum Trafficlight {
         GREEN(30) {

             @Override
             public Trafficlight nextLigth() {
                 return RED;
             }
         },
         RED(30) {

             @Override
             public Trafficlight nextLigth() {
                 return YELLOW;
             }
         },
         YELLOW(10) {

             @Override
             public Trafficlight nextLigth() {
                 return GREEN;
             }
         };
         public abstract Trafficlight nextLigth();

         private int time;

         // 構造方法
         private Trafficlight(int time) {
             this.time = time;
         }

         public int getTime(){
             return time;
         }

     }

 }