Question

现在，我有一个各种值的枚举，我想知道是否有任何方法可以在枚举中存储方法。例如：

public enum myEnum{

     one("first", callFirstMethod),
     two("second", callSecondMethod), 
     three("last", callThirdMethod);

     public String message;
     public Method met;

     myEnum(String m, Method meth){
         message = m;
         met = meth;
     }
}

public class myMethods{
    public void callFirstMethod(){
        System.out.println("First!");
    }

    public void callSecondMethod(){
        System.out.println("Second!");
    }

    public void callThirdMethod(){
        System.out.println("Third!");
    }
}

然后使用类似的东西：方法method = myEnum.one.callFirstMethod（）;

调用方法。这样的事情可能吗？我试过在谷歌上玩/环顾四周，没有什么事实真的出现了。谢谢你的帮助！

Answer 1

使用接口并将接口实例作为第二个枚举参数，或者为其提供在实例中实现的抽象方法。例如：

enum MyEnum {

   ONE("first", new MyInterface() {

      @Override
      public void commonMethod() {
         System.out.println("First!");
      }
   }) {
      @Override
      public void abstractEnumMethod() {
         System.out.println("abstract enum meuthod, first!");
      }
   }, 
   TWO("second", new MyInterface() {

      @Override
      public void commonMethod() {
         System.out.println("Second!");
      }
   }) {
      @Override
      public void abstractEnumMethod() {
         System.out.println("abstract enum meuthod, second!");
      }
   }, 
   THREE("last", new MyInterface() {

      @Override
      public void commonMethod() {
         System.out.println("Third!");
      }
   }) {
      @Override
      public void abstractEnumMethod() {
         System.out.println("abstract enum meuthod, third!");
      }
   };

   private String message;
   private MyInterface myType;

   private MyEnum(String m, MyInterface myType) {
      message = m;
      this.myType = myType;
   }

   public String getMessage() {
      return message;
   }

   public MyInterface getMyType() {
      return myType;
   }

   public void enumMethod() {
      System.out.println(message);
   }

   public abstract void abstractEnumMethod();
}

interface MyInterface {
   void commonMethod();
}

Answer 2

答案全部取决于你想要实现的目标。例如，您可以在enum内提供一个通用方法，并检查调用它的枚举实例...

public class TestEnum {

    public static void main(String[] args) {
        MyEnum.ONE.doStuff();
        MyEnum.TWO.doStuff();
        MyEnum.THREE.doStuff();
    }

    public enum MyEnum {

        ONE("first"),
        TWO("second"),
        THREE("last");

        public String message;

        MyEnum(String m) {
            message = m;
        }

        public void doStuff() {
            System.out.println(name());
            if (ONE.equals(this)) {
                System.out.println("...Do stuff for one");
            } else if (TWO.equals(this)) {
                System.out.println("...Do stuff for two");
            } else if (THREE.equals(this)) {
                System.out.println("...Do stuff for three");
            }
        }
    }

}

哪些输出......

one
...Do stuff for one
two
...Do stuff for two
three
...Do stuff for three

在Enum中存储方法？

2 个答案: