如何计算方法调用和对应的开始到结束编号​​？

Question

我有以下代码，有没有一种很好的方法来计算State enum中的数字？

我想将StateHolders的函数移动到State枚举，但我不知道如何将起始编号与结束编号对应。

public enum State{
   START("start"),
   END("end");

   public String msg;

   private State(String msg){
      this.msg = msg;
   }       
}

public class StateHolder{

   private static AtomicInteger counter = new AtomicInteger();
   private int current;

   public String start(){
      current = counter.getAndIncrement();
      return State.START.msg + " " + current;
   }

   public String end(){
      return State.END.msg + " " + current;
   }
} 


public static void main(String[] args){

    StateHolder sh1 = new StateHolder();
    StateHolder sh2 = new StateHolder();

    System.out.println(sh1.start); // start 0
    System.out.println(sh2.start); // start 1
    System.out.println(sh1.end); // end 0
    System.out.println(sh2.end); // end 1

}

Answer 1

这个怎么样：

public enum State {
...

    private static AtomicInteger counter = new AtomicInteger();

    public AtomicInteger counter() {
        return counter;
    }
...

}

public class StateHolder {

    private int current;

    public String start() {
        current = State.START.counter().getAndIncrement();
        return State.START.msg + " " + current;
    }
...
}