Skip to main content
Software Engineering

You are not logged in. Your edit will be placed in a queue until it is peer reviewed.

We welcome edits that make the post easier to understand and more valuable for readers. Because community members review edits, please try to make the post substantially better than how you found it, for example, by fixing grammar or adding additional resources and hyperlinks.

14
  • 3
    +1 for "ride a coach and horses through" anything. It's a great phrase that I wish I heard more. Commented Mar 11, 2016 at 19:38
  • 2
    If somebody needs to subclass your class, perhaps he should have access to your safeguards? And if you don't want somebody to change your safeguards to achieve some goal, perhaps don't share the code? It works like this in Ruby - private is more or less of a recommendation. Commented Mar 12, 2016 at 10:05
  • 3
    @AdamLibuša "Don't share the code"? As soon as you publish any DLL at all, you're sharing the code - all the structures and methods and everything are there for the whole world to see, especially with languages that support reflection by default. Everyone can do whatever they want with "your code" - private is just a way of saying "don't touch these", and have it enforced within the compiler contract. In systems like .NET, this also has important security implications - you can only touch others' privates when you have full trust (basically the equivalent of admin/root access). Commented Mar 14, 2016 at 9:06
  • 2
    @AdamLibuša I think your confusion mainly stems from the different OOP approaches different languages took. The root of OOP (as originally defined) is messaging - that means that everything is private, except for the messages you respond to. In most OOPish languages, this is exposed as "keep your data private" - a way to make the public interface as small as possible. The only way the user (be it a subclass or another class) has to manipulate your class is through the public interface you defined - similar to how you usually use the steering wheel and pedals to drive your car :) Commented Mar 14, 2016 at 9:09
  • 3
    @Luaan +1 for when it's okay to touch others' privates! Commented Mar 14, 2016 at 14:30