Comment by jolt42
5 days ago
My OO projects were usually in Java with a DB. They all ran afoul of what Martin Fowler calls the Anemic Domain Model. Basically your objects are data-only, so there's no benefit. In addition Spring injection became ubiquitous, and further killed objects with behavior. The only project using a DB and had objects with behavior was an old one that happened to use TopLink as an OR mapping.
> Basically your objects are data-only, so there's no benefit.
This makes me wonder why most of us use Java at all. In your typical web app project, classes just feel like either:
1) Data structures. This I suspect is a result of ORM's not really being ORM's but actually "Structural Relational Mappers".
- or -
2) Namespaces to dump functions. These are your run-of-the-mill "utils" classes or "service" classes, etc.
The more I work in Java, the more I feel friction between the language, its identity(OO beginning to incorporate functional ideas), and how people write in it.
> why most of us use Java at all
Java was the first popular language to push static analysis for correctness. It was the "if it compiles, it runs" language of its day, what meant that managers could hire a couple of bad developers by mistake and it wouldn't destroy the entire team's productivity.
I'm not sure that position lasted for even 5 years. But it had a very unique and relevant value proposition at the time.
OCaml would like to have a word with you. In 2005 it already had better static analysis and correctness on object oriented stuff than what Java struggles to approach today.
But Java has better marketing.
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A lot of that is down to how people rely on frameworks that force them into "convenient" abstractions. Like Spring and Hibernate. But those are not the language. They represent a (vocal) subset of programmers.
You don't need an ORM or an overgrown dependency injection framework to create a webapp in Java.
Service classes are the thing I hate most. They’re just namespaces for functions. They’re a product of Java not being able to have top level functions.
Not being able to have top level functions is a feature, not a bug.
You can declare static methods on interfaces in Java, which means you could call things like Users.create("Foobar") if you wanted to.
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They're just namespaces for functions, and... why is that so bad? Of all the reasons I hate Java, this isn't one of them, it's whatever.
You are so ready : https://fsharpforfunandprofit.com/rop/
The separation of functions and records..
I've read his book "Domain Modeling Made Functional" without much prior knowledge of F#. He provides some compelling examples and some of it ended up inspiring how I write OO code. F# seems cool but it felt like it was close to being extinct.
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Java is a waste of time for the reasons you said. People use it for legacy reasons. Back then, the alternatives like JS just weren't there yet in several spaces like backend. Your alternatives were even more cumbersome like C++.
> People use it for legacy reasons
This is so incredibly wrong it must be a troll.
OO fatigue is a healthy symptom of readiness to move to clojure, where data and functions are free to live without encapsulation. No king of nouns, no king of execution!
Why did you create an anemic domain model?
Java has had "data carriers" in the form of records for a while now. Immutable(ish), low boilerblate, convenient.
Records are great when doing more "data oriented programming".
I don't think anyone sets out to make an anemic domain model, it just happens. Lots of developers start with POJO's for JPA models and then never advance them into being full fledged objects when the requirements develop.
Surely that's a conscious design decision? Deciding to create data-carrying POJOs with JPA annotations is a valid strategy. Mixing in a bunch of logic and non-JPA state with them is a recipe for disaster. If you want your classes to Do Stuff, you have to design them to Do Stuff.
I dislike the term "anemic domain model", it casts a value judgment which I think is unwarranted. There's a spectrum from anemic to obese (for want of a better word). There are tradeoffs all along that spectrum. Finding a sweet spot will depend heavily on what you're doing, why you're doing it, what your team is comfortable with etc.
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That's not object oriented though
Does it have to be? Java is a hybrid paradigm language. It's perfectly fine to write data-oriented code. And if you're using an anemic model, there's no point paying the overhead price of fully fledged classes.
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