在PHP中扩展抽象类时的方法可见性

In my abstract class My_Class, I have a method My_Class::foo() that's called from within another method belonging to the class. For example:

在我的抽象类My_Class中,我有一个方法My_Class :: foo(),它是从属于该类的另一个方法中调用的。例如:

abstract class My_Class {
    function foo() {
        // Stuff.
    }

    function bar() {
        $this->foo();
    }

    // More methods etc...
}

Now, I'm in the process of extending my abstract class. For example:

现在,我正在扩展我的抽象类。例如:

class My_Class_Extended extends My_Class {

}

As you'll know, both My_Class::foo() and My_Class::bar() are inherited by My_Class_Extended.

如您所知,My_Class :: foo()和My_Class :: bar()都由My_Class_Extended继承。

I never want My_Class::foo() to be called outside of My_Class or My_Class_Extended so I know not to make its visibility public. My problem is, I'm unsure whether to make its visibility protected or private.

我从不希望在My_Class或My_Class_Extended之外调用My_Class :: foo(),所以我知道不要公开它的可见性。我的问题是,我不确定是否保护其可见性或保密。

My question

Considering how I'm calling My_Class::foo() in the above scenario, should it be made protected or private? I'm not sure if the call to My_Class::foo() is coming from the child or parent class.

考虑到我在上面的场景中如何调用My_Class :: foo(),它应该被保护还是私有?我不确定对My_Class :: foo()的调用是来自子类还是父类。

Thanks in advance.

提前致谢。

1 个解决方案

#1

One-line: protected, because you want your child classes have access

单行:受保护,因为您希望您的子类具有访问权限

The visibility modifiers work like this:

可见性修饰符的工作方式如下:

public: visible from everywhere.

公众:从各处可见。

- $c = new My_Class_Extended(); $c->thisIsPublic();. This doesn't work with private or protected

$ c = new My_Class_Extended(); $ C-> thisIsPublic();.这不适用于私人或受保护

protected: visible inside of the class and it's child classes

protected:在类内部可见,它是子类

- You can only call these functions inside of a function belonging to a class that derives from your parent class, or the parent class itself.

您只能在属于从父类或父类本身派生的类的函数内调用这些函数。

private: Only visible for the class it's defined in. You cannot call private functions in child classes, nor outside of the class.

private:仅对其定义的类可见。您不能在子类中调用私有函数,也不能在类之外调用私函数。

The modifiers are ordered inclusively. So a protected is more restrictive than public, and private is more restrictive than protected.

修饰语包含在内。因此受保护比公共更具限制性,而私有受限制比受保护更严格。

You want protected, because you want to call them inside a child class, but not outside of it.

你想要保护,因为你想在子类中调用它们,但不是在它之外。

By the way: In your context, the abstract keyword only ensures that you cannot create an instance from My_Class.

顺便说一句:在您的上下文中,abstract关键字仅确保您无法从My_Class创建实例。

#1