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:

我想有一个Java类，它提供一个公共静态方法，它做了什么。这只是为了封装的目的（让一切在一个单独的类中重要）...

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)...

这个类既不应被实例化，也不应被扩展。这使我写：

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，它是禁止的）。

(though I knew, it is forbidden).

我也知道，我可以使这个类完全覆盖标准构造函数，而

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

但是这在我看来更像是一个解决方法，应该更有可能通过最终的抽象类...

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

我讨厌解决方法。

推荐答案

参考：有效的Java第2版第4项强制不可否定性与私有构造函数

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() {}
}

这篇关于Java最终抽象类的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！