Java最终抽象类 [英] Java final abstract class

问题描述

我有一个很简单的问题:

I have a quite simple question:

我想要一个 Java 类，它提供一个公共静态方法，它可以做一些事情.这只是为了封装的目的(将所有重要的东西都放在一个单独的类中)...

I want to have a Java Class, which provides one public static method, which does something. This is just for encapsulating purposes (to have everything important within one separate class)...

这个类既不应该被实例化，也不应该被扩展.这让我写道:

This class should neither be instantiated, nor being extended. That made me write:

final abstract class MyClass {
   static void myMethod() {
      ...
   }
   ... // More private methods and fields...
}

(虽然我知道，这是被禁止的).

(though I knew, it is forbidden).

我也知道，我可以使这个类完全成为最终类，并在使其私有的同时覆盖标准构造函数.

I also know, that I can make this class solely final and override the standard constructor while making it private.

但这在我看来更像是一种解决方法"，应该更有可能由最终抽象类来完成...

But this seems to me more like a "Workaround" and SHOULD more likely be done by final abstract class...

而且我讨厌变通办法.所以只是为了我自己的兴趣:还有其他更好的方法吗?

And I hate workarounds. So just for my own interest: Is there another, better way?

推荐答案

参考:Effective Java 2nd Edition Item 4Enforce noninstantiability with a private constructor"

Reference: Effective Java 2nd Edition Item 4 "Enforce noninstantiability with a private constructor"

public final class MyClass { //final not required but clearly states intention
    //private default constructor ==> can't be instantiated
    //side effect: class is final because it can't be subclassed:
    //super() can't be called from subclasses
    private MyClass() {
        throw new AssertionError()
    }

    //...
    public static void doSomething() {}
}

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