如何修复操作切换语句

Question

在这个称为AClass的类中，我尝试制作一个switch语句，该语句将使用在两个值之间输入的运算符。

public interface Operation {
  public enum Operator {Add, Sub, Mult, Div, Rem}
}


import java.util.*;
import java.io.*;

public class AClass<I> implements Operation {

    AClass <Integer> leftoperand = new AClass <Integer>();
    AClass <Operator> operation = new AClass <Operator>();
    AClass <Integer> rightoperand = new AClass <Integer>(); 

  public Integer value (SClass sc) {
    switch (operation) {
        case Add:
            return leftoperand.value(sc) + rightoperand.value(sc);
        case Sub:
            return leftoperand.value(sc) - rightoperand.value(sc);
        case Mult:
            return leftoperand.value(sc) * rightoperand.value(sc);
        case Div:
            return leftoperand.value(sc) / rightoperand.value(sc);
        case Rem:
            return leftoperand.value(sc) % rightoperand.value(sc);
    }
  }

  public String toString() {
   return "(" + leftoperand + "," + operation + "," + rightoperand + ")";
  }
}
Error: incompatible types: AClass<AClass.Operator> cannot be converted to int

Error: cannot find symbol
  symbol:   variable Add
  location: class AClass<I>

Error: cannot find symbol
  symbol:   variable Sub
  location: class AClass<I>

Error: cannot find symbol
  symbol:   variable Mult
  location: class AClass<I>

Error: cannot find symbol
  symbol:   variable Div
  location: class AClass<I>

Error: cannot find symbol
  symbol:   variable Rem
  location: class AClass<I>

并且从切换（操作）行开始，我收到了一些错误。我该如何解决这个问题？另外，我可以只将枚举运算符插入AClass内而不使用接口吗？

Answer 1

Java switch语句不支持所有类。从Java文档中，与if-then和if-then-else语句不同，switch语句可以具有许多可能的执行路径。开关适用于byte，short，char和int基本数据类型。它也适用于枚举类型（在Enum Types中讨论），String类以及一些包装某些基本类型的特殊类：Character，Byte，Short和Integer（在Numbers和Strings中讨论）。

AClass <Operator> operation = new AClass <Operator>(); // will not work
Operator operation = Operator.ADD; // will work since operator is an enum;