我可以静态导入私有子类吗？

发布于 2024-08-17 16:42:08 字数 441 浏览 5 评论 0原文

我有一个私有的枚举，不能暴露在课堂之外。无论如何，我可以执行该类型的静态导入，这样我就不必每次都键入枚举类型吗？或者有更好的方法来写这个吗？例子：

package kip.test;

import static kip.test.Test.MyEnum.*; //compile error

public class Test
{
  private static enum MyEnum { DOG, CAT }

  public static void main (String [] args)
  {
    MyEnum dog = MyEnum.DOG; //this works but I don't want to type "MyEnum"
    MyEnum cat = CAT; //compile error, but this is what I want to do
  }
}

原文

I have an enum which is private, not to be exposed outside of the class. Is there anyway I can do a static import of that type, so that I don't have to type the enum type each time? Or is there a better way to write this? Example:

package kip.test;

import static kip.test.Test.MyEnum.*; //compile error

public class Test
{
  private static enum MyEnum { DOG, CAT }

  public static void main (String [] args)
  {
    MyEnum dog = MyEnum.DOG; //this works but I don't want to type "MyEnum"
    MyEnum cat = CAT; //compile error, but this is what I want to do
  }
}

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亚希 2024-08-24 16:42:08

您可以使用无修饰符访问级别，即

enum MyEnum { DOG, CAT }

MyEnum 对其他包中的类和任何子类中的类均不可见。它是最接近的私有形式，但可以让您避免显式引用 MyEnum。

You can use the no-modifier access level, i.e.

enum MyEnum { DOG, CAT }

MyEnum will not be visible to classes from other packages neither from any subclass. It is the closest form of private, yet letting you avoid explicitly referencing MyEnum.

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逆光飞翔i 2024-08-24 16:42:08

考虑到您可以完全限定地访问该字段，我想说这是编译器（或语言规范）中的一个错误，您无法静态导入它。

我建议您对枚举包进行保护。

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喜你已久 2024-08-24 16:42:08

将某些代码移至枚举的（静态）方法中可能（也可能不）合理。

如果按下，您可以复制外部类中的静态字段。

private static final MyEnum CAT = MyEnum.CAT;
private static final MyEnum DOG = MyEnum.DOG;

恶心，但有可能。

It may (or may not) be reasonable to move some of the code into (static) methods of the enum.

If pressed, you could duplicate the static fields in the outer class.

private static final MyEnum CAT = MyEnum.CAT;
private static final MyEnum DOG = MyEnum.DOG;

Icky, but a possibility.

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靖瑶 2024-08-24 16:42:08

或者有更好的写法吗？

如果您的主要目标是引用没有限定枚举标识符的项目，并私下维护此列表，则可以完全废弃 enum 类型并使用普通的私有静态常量。

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月棠 2024-08-24 16:42:08

您可以简单地将代码编写在枚举本身内。

public enum MyEnum {
DOG, CAT;
public static void main(String[] args) {
    MyEnum dog = MyEnum.DOG; // this works but I don't want to have to type
                                // MyEnum
    MyEnum cat = CAT; // compile error, but this is what I want to do
}
 }

私有枚举可以在没有其类的情况下进行引用的另一个地方是在 switch 语句中：

private static enum MyEnum {
    DOG, CAT
}

public static void main(String[] args) {
    MyEnum e = null;
    switch (e) {
    case DOG:
    case CAT:
    }
}

You could simply write your code inside the enum itself.

public enum MyEnum {
DOG, CAT;
public static void main(String[] args) {
    MyEnum dog = MyEnum.DOG; // this works but I don't want to have to type
                                // MyEnum
    MyEnum cat = CAT; // compile error, but this is what I want to do
}
 }

The other place where private enums can be references without their class is in a switch statement:

private static enum MyEnum {
    DOG, CAT
}

public static void main(String[] args) {
    MyEnum e = null;
    switch (e) {
    case DOG:
    case CAT:
    }
}

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