As a Java engineer in the web development industry for several years now, having heard multiple times that X is good because of SOLID principles or Y is bad because it breaks SOLID principles, and having to memorize the “good” ways to do everything before an interview etc, I find it harder and harder to do when I really start to dive into the real reason I’m doing something in a particular way.
One example is creating an interface for every goddamn class I make because of “loose coupling” when in reality none of these classes are ever going to have an alternative implementation.
Also the more I get into languages like Rust, the more these doubts are increasing and leading me to believe that most of it is just dogma that has gone far beyond its initial motivations and goals and is now just a mindless OOP circlejerk.
There are definitely occasions when these principles do make sense, especially in an OOP environment, and they can also make some design patterns really satisfying and easy.
What are your opinions on this?
I think a large part of interfaces everywhere comes from unit testing and class composition. I had to create an interface for a Time class because I needed to test for cases around midnight. It would be nice if testing frameworks allowed you to mock concrete classes (maybe you can? I haven’t looked into it honestly) it could reduce the number of unnecessary interfaces.
I’ve had to do that too, for tests specifically as well, and making clocks an interface on the spot was trivial. I did it when I needed it though, and not ahead of time.
A Time interface is waaaay too broad. Turns out, I only needed something something to give me programmable ticks for my tests, which is much narrower in scope than abstracting something as general as time.
I’d say abstractions designed to support tests need to be very narrow in scope, and focused on solving the problem at hand.
You’ve been able to mock concrete classes in Java for like a decade or so, probably longer. As long as I can remember at least. Using Mockito it’s super easy.
At least in C# with Moq you can only mock virtual methods of concrete classes, so using interfaces is still nicer in general.
Yeah Moq is what I used when I worked with .NET.
On an unrelated note; god I miss .NET so much. Fuck Microsoft and all that, but man C# and .NET feels so good for enterprise stuff compared to everything else I’ve worked with.
This was definitely true in the Java world when mocking frameworks only allowed you to mock interfaces.