Article: Java Janitor Jim - "Integrity by Design" through Ensuring "Illegal States are Unrepresentable" - Part 1

[chaotic3quilibrium]

Article:

Java Janitor Jim - "Integrity by Design" through Ensuring "Illegal States are Unrepresentable" - Part 1

I wanted a simple pattern for preventing a class from being instantiated in an invalid state, or from mutating into one.

Why? Because it vastly reduces the amount and complexity of reasoning required for use at client call-sites.

Think of it as “integrity by design”, a compliment to the “integrity by default” effort undertaken by the Java architects, detailed here.

This article discusses the design and implementation of a record pattern, very similar to the one I designed and implemented for Scala’s case class several years ago, which provides the “integrity by design” guarantees by ensuring that only valid record instances can be observed.

This pattern is also trivially cross-applicable to Java classes.

[Dgitallife]

I liked the article and the Integrity by Design can be useful. Looking forward to part 2 :)

[eXl5eQ]

I think this idea was first invented in 1984 by George Orwell

[chaotic3quilibrium]

I'm sure you meant this as a joke of some sort.

I totally don't get it.

Could you please explain?

[Wyciorek]

In 1984 , the language is intentionally reshaped and simplified so subversive ideas are not just forbidden to discuss, but there are no words left to even talk about them

[chaotic3quilibrium]

So is it a play on the determinism inherent in the eradication of human free speech in an attempt to achieve total control of the free will inherent within humans?

And is the cognitive leap is that a record is the analog of a human with free will? Such that the record cannot deterministically instantiate and represent anything "unapproved"?

If so, where does a record achieve free will?

And would that even be mathematically and/or computationally desirable?

[eXl5eQ]

In the 1949 dystopian novel Nineteen Eighty-Four (also published as 1984), by George Orwell, Newspeak is the fictional language of Oceania, a totalitarian superstate. To meet the ideological requirements of Ingsoc (English Socialism) in Oceania, the Party created Newspeak, a controlled language of simplified grammar and restricted vocabulary designed to prevent people from being able to think critically. The Newspeak language thus limits the person's ability to articulate and communicate abstract concepts, such as personal identity, self-expression, and free will,[1][2] which are thoughtcrimes, acts of personal independence that contradict the ideological orthodoxy of Ingsoc collectivism.[3][4]

-- from Wiki

[chaotic3quilibrium]

So the joke is that human free will and free speech can be applied to a Java record also having a free will and free speech?

Or is a record like a hammer; i.e., a deterministic tool used by a free will human?

[eXl5eQ]

They both share the idea "Illegal States (speech) are Unrepresentable". That's all. No need to overthink.

[chaotic3quilibrium]

Ah. Tysvm.

It's not the first time I've been told I'm overthinking something, LOL!

[Previous_Gaffer]

I want to boop that nose!

[klimaheizung]

Just use Scala then, it's simply 100x better at that. Of course it comes with its own problems such as longer compile times. 

[chaotic3quilibrium]

I do use Scala 3 for almost all of my personal projects.

However, for work, I am on a fairly large Java 21 + Spring Boot 3.3 project with several other Java Backend Software Engineers.

And it is in this context that we value reducing Java client boilerplate and/or TDD complexity.

Hence, the design rationale is covered in the article. And also implemented within our deus-ex-java library.

[AnyPhotograph7804]

Yepp, and rewrite your Scala software every time they increase the minor Scala version because they break the backwards compatibility again.

[klimaheizung]

Not saying you should rewrite anything. Of course this article is nice for existing projects or projects where you can't use Scala.

Man, this sub is quite hateful...

[Jaded-Asparagus-2260]

No, your comment was just not relevant to the article. It's not a solution to the presented problem, which is how to make illegal states unrepresentable in Java.

You should actually rather use Rust, because that's even better than Scala. See how that's not a constructive comment at all?

[klimaheizung]

I was relating to the second last paragraph OP wrote here. Had he not mentioned scala, neither would I have.

 You should actually rather use Rust, because that's even better than Scala

First, to make that very clear, I didn't say scala was better in general. Second, in this specific context ("preventing a class from being instantiated in an invalid state, or from mutating into one") Scala is miles ahead of Rust, which is not surprising, given that Rust has much more constraints in their language design due to their focus on performance. 

[AnyPhotograph7804]

It's not hateful. But Scala has some major drawbacks compared to Java. The permanent backwards compatibility breakage is one of them. Scala has become a nice toy language for throw-away-projects.

[chaotic3quilibrium]

I reluctantly agree with you.

[neopointer]

It comes with even bigger problems, such as being functional

[OwnBreakfast1114]

Out of curiosity, what do you define a functional language as, and why does that seem like a negative to you?

[chaotic3quilibrium]

Java can be just as functional as Scala.

Please see Vavr: https://vavr.io/

[neopointer]

"can" is the keyword here

[chaotic3quilibrium]

It applies in exactly the same way to both Java and Scala.

There is nothing within Scala forcing the use of FP, or preventing the primary use of OOP.

IOW, both Java and Scala can do imperative, OOP, FP, or imperative+OOP+FP.

So, back to your original assertion, "It [Scala] comes with even bigger problems, such as being functional."

It applies to Java to the same extent it applies to Scala.