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?

  • Corbin@programming.devEnglish
    2·
    1 day ago

    Java is bad but object-based message-passing environments are good. Classes are bad, prototypes are also bad, and mixins are unsound. That all said, you’ve not understood SOLID yet! S and O say that just because one class is Turing-complete (with general recursion, calling itself) does not mean that one class is the optimal design; they can be seen as opinions rather than hard rules. L is literally a theorem of any non-shitty type system; the fact that it fails in Java should be seen as a fault of Java. I is merely the idea that a class doesn’t have to implement every interface or be coercible to any type; that is, there can be non-printable non-callable non-serializable objects. Finally, D is merely a consequence of objects not being functions; when we want to apply a functionf to a value x but both are actually objects, both f.call(x) and x.getCalled(f) open a new stack frame with f and x local, and all of the details are encapsulation details.

    So, 40%, maybe? S really is not that unreasonable on its own; it reminds me of a classic movie moment from “Meet the Parents” about how a suitcase manufacturer may have produced more than one suitcase. We do intend to allocate more than one object in the course of operating the system! But also it perhaps goes too far in encouraging folks to break up objects that are fine as-is. O makes a lot of sense from the perspective that code is sometimes write-once immutable such that a new version of a package can add new classes to a system but cannot change existing classes. Outside of that perspective, it’s not at all helpful, because sometimes it really does make sense to refactor a codebase in order to more efficiently use some improved interface.