为什么要用Java公开私有内部类成员？ [英] Why make private inner class member public in Java?

问题描述

如果仍无法在包含类的外部访问该私有内部类的成员，则在Java中声明该成员的原因是什么？

What is the reason of declaring a member of a private inner class public in Java if it still can't be accessed outside of containing class? Or can it?

public class DataStructure {
    // ...

    private class InnerEvenIterator {
        // ...

        public boolean hasNext() { // Why public?
            // ...
        }
    }
}

推荐答案

如果 InnerEvenIterator 类没有扩展任何类或实现任何接口，我认为这是无稽之谈，因为没有其他类可以访问它的任何实例。

If the InnerEvenIterator class does not extend any class or implement any interface, I think it is nonsense because no other class can access any instance of it.

但是，如果它扩展或实现了任何其他非私有类或接口，则是有意义的。示例：

However, if it extends or implements any other non private class or interface, it makes sense. An example:

interface EvenIterator {
    public boolean hasNext();
}


public class DataStructure {
    // ...

    private class InnerEvenIterator implements EvenIterator{
        // ...

        public boolean hasNext() { // Why public?
            // ...
        }
    }

    InnerEvenIterator iterator;

    public EvenIterator getIterator(){
         return iterator;
    }     

}

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