Let me start by saying (as someone who has written a few technical books of his own)—Congratulations!
I am sure you (assuming this is your first book) are learning that this is a labor of love, and I wish you the very best in this endeavor. You should be proud!
I was exposed to "data oriented programming" thanks to Clojure—wherein maps/sets are the constructs used to pass data (as plain data) around, with simple functions that work with the data, as opposed to the traditional OO (hello ORM) that mangles data to fit some weird hierarchy.
Java's recent innovations certainly make this a lot easier, and I am glad someone is looking at propagating a much needed message.
I will take a look at the book, but I wish you the very best.
I am also very interested in how this work in practice. With OOP at least you know the shape of your data structure as opposed to the hash map as a mere container type.
I am an OOP programmer going back to the late 80s (including the cfront days of C++), and a serious user of Python since 2007.
In Python, I sometimes try data-oriented programming, using lists and dicts to structure data. And I find that it does not work well. Once I get two or more levels of nesting, I find it far too easy to get confused about which level I'm on, which is not helped by Python's lack of strong typing. In these situations, I often introduce objects that wrap the map or dict, and have methods that make sense for that level. In other words, the objects can be viewed as providing clear documentation for the whole nested structure, and how it can be navigated.
>Once I get two or more levels of nesting, I find it far too easy to get confused about which level I'm on
Author here, I agree with you. I have the working memory of a small pigeon.
The flavor of data orientation we cover in the book leverages strongly typed representations of data (as opposed to using hash maps everywhere). So you'll always know what's shape it's in (and the compiler enforces it!). We spend a lot of time exploring the role that the type system can play in our programming and how we represent data.
Given the strongly typed flavour of data oriented programming, I wonder if you have any thoughts on the "proliferation of types" problem. How to avoid, especially in a nominally typed language like Java, an explosion of aggregate types for every context where there may be a slight change in what fields are present, what their types are, and which ones are optional. Basically, Rich Hickey's Maybe Not talk.
record Make(makeId, name)
record Model(modelId, name)
record Car(make, model, year)
record Car(makeId, modelId, year)
record Car(make, model)
record Car(makeId, modelId)
record Car(make, year)
record Car(makeId, year)
record Car(make, model, year, colour)
record Car(makeId, modelId, year, colour)
record Car(year, colour)
....Hickey is great at trash-talking other languages. In the case of Car you might build a set of builders where you write
Car.builder().make(“Buick”).model(“LeSabre”).build()
In the field of ontology (say OWL and RDF) there is a very different viewpoint about ‘Classes’ in the objects gain classes as they gain attributes. :Taylor_Swift is a :Person because she has a :birthDate, :birthPlace and such but was not initially a :Musician until she :playsInstrument, :recordedTrack, :performedConcert and such. Most languages have object systems like Java or C++ where a Person can’t start out as not a Musician but become one later like the way they can in real life.
Notably in a system like the the terrible asymmetry of where does an attribute really belong is resolved, as in real life you don’t have to say it is primary that Taylor Swift recorded the Album Fearless or that Fearless was recorded by Taylor Swift.
It’s a really fascinating question in my mind how you create a ‘meta object facility’ that puts a more powerful object system on your fingers in a language like Java or Python, for instance you can have something like
taylorSwift.as(Musician.class)
taylorSwift.isA(Musician.class)
TaylorSwift instanceof MetaObject.classI haven't yet had the luxury to experiment with the latest version of Java, but this is one of the reasons why I wish Java introduced named parameters the say way kotlin and scala do.
Eg:
data class Make(makeId: String, name: String)
data class Model(modelId: String, name: String)
data class Car(make: Make, model: Model, year: String, ...)
val v1 = Car(make = myMake1, model = myModel1, year = "2023", ...)
val v1 = Car(model = myModel1, make = myMake1, year = "2023", ...)Once withers land, I think you could approximate this by letting your record class have a zero argument constructor which sets every field to some blank value, and then fill the fields using `with`.
var x = new Car() with { make = "Volvo"; year = "2023"; };
record Car(String make, String year) {
Car {
Objects.requireNonNull(make);
Objects.requireNonNull(year);
}
record Builder(String make, String year) {
Car build() {
return new Car(make, year);
}
}
}
var x = new Car.Builder() with { make = "Volvo"; year = "2023"; }.build();
> Given the strongly typed flavour of data oriented programming, I wonder if you have any thoughts on the "proliferation of types" problem.
Not a problem.
You're just making your life needlessly hard and blaming Java for the problems you're creating for yourself.
This represents, coincidentally, the bulk of the problems pinned on Java.
Everywhere else the problem you described is a variant of an anti-pattern and code smell widely known as telescoping constructor pattern.
The problems caused by telescoping constructors have a bunch of known cures:
- builder pattern (Lombok supports this, by the way),
- the parameter object pattern (builder pattern's poor cousin)
- semantically-appropriate factory methods.
The whole reason behind domain models taking the center stage when developing a software project is that you build your whole project around a small set of types with the necessary and sufficient expressiveness to represent your problem domain.
Also, "explosion of aggregate types" can only become a problem if for some reason you don't introduce support for type conversion when introducing specialized types.
I have a long convoluted answer to this.
I love that talk (and most of Rich's stuff). I consider myself a Clojure fanboy that got converted to the dark side of strong static typing.
I think, to some degree, he actually answers that question as part of his talk (in between beating up nominal types). Optionality often pops up in place of understanding (or representing) that data has a context. If you model your program so that it has "15 maybe sheep," then... you'll have 15 "maybe sheep" you've got to deal with.
The possible combinations of all data types that could be made is very different from the subset that actually express themselves in our programs. Meaning, the actual "explosion" is fairly constrained in practice because (most) businesses can't function under combinatorial pressures. There's some stuff that matters, and some stuff that doesn't. We only have to apply typing rigor to the stuff that matters.
Where I do find type explosions tedious and annoying is not in expressing every possible combination, but in trying to express the slow accretion of information. (I think he talks about this in one of his talks, too). Invoice, then InvoiceWithCustomer, then InvoiceWithCustomerAndId, etc... the world that microservices have doomed us to representing.
I don't know a good way to model that without intersection types or something like Rows in purescript. In Java, it's a pain point for sure.
Hopefully your domain is sane enough that you can read nearly all the data you are going to use up front, then pass it on to your pure functions. Speaking from a Java perspective.
My sense is that what's needed is a generalization of the kinds of features offered by TypeScript for mapping types to new types (e.g. Partial<T>) "arithmetically".
For example I often really directly want to express is "T but minus/plus this field" with the transformations that attach or detach fields automated.
In an ideal world I would like to define what a "base" domain object is shaped like, and then express the differences from it I care about (optionalizing, adding, removing, etc).
For example, I might have a Widget that must always have an ID but when I am creating a new Widget I could just write "Widget - {.id}" rather than have to define an entire WidgetCreateDTO or some such.
Do you mean in TypeScript or in another language?
In TS the `Omit<T, K>` type can be used to remove stuff, and intersection can be used to add stuff
> For example, I might have a Widget that must always have an ID but when I am creating a new Widget I could just write "Widget - {.id}" rather than have to define an entire WidgetCreateDTO or some such.
In this case you're preferring terseness vs a true representation of the meaning of the type. Assuming that a Widget needs an ID, having another type to express a Widget creation data makes sense, it's more verbose but it does represent the actual functioning better, you pass data that will be used to create a valid Widget in its own type (your WidgetCreationDTO), getting a Widget as a result of the action.
> Assuming that a Widget needs an ID, having another type to express a Widget creation data makes sense, it's more verbose but it does represent the actual functioning better
I agree with this logically. The problem is that the proliferation of such types for various use cases is extremely detrimental to the development process (many more places need to be updated) and it's all too easy for a change to be improperly propagated.
What you're saying is correct and appropriate I think for mature codebases with "settled" domains and projects with mature testing and QA processes that are well into maintenance over exploration/iteration. But on the way there, the overhead induced by a single domain object whose exact definition is unstable potentially proliferating a dozen types is developmentally/procedurally toxic.
To put a finer point on it: be fully explicit when rate of change is expected to be slow, but when rate of change is expected to be high favor making changes easy.
> What you're saying is correct and appropriate I think for mature codebases with "settled" domains and projects with mature testing and QA processes that are well into maintenance over exploration/iteration. But on the way there, the overhead induced by a single domain object whose exact definition is unstable potentially proliferating a dozen types is developmentally/procedurally toxic.
> To put a finer point on it: be fully explicit when rate of change is expected to be slow, but when rate of change is expected to be high favor making changes easy.
I agree with the gist of it, at the same time I've worked in many projects which did not care about defining a difference between those types of data in their beginning, and since they naturally change fast they accrued a large amount of technical debt quickly. Even more when those projects were in dynamically typed languages like Python or Ruby, relying just on test cases to do rather big refactorings to extrincate those logical parts are quite cumbersome, leading to avoidance to refactor into proper data structures afterwards.
Through experience I believe you need to strike a balance, if the project is in fluid motion you do need to care more about easiness of change until it settles but separating the actions (representation of a full fledged entity vs representation of a request/action to create the entity, etc.) is not a huge overhead given the benefits down the line (1-3 years) when the project matures. Balancing this is tricky though, and the main reason why any greenfield project requires experienced people to decide when flexibility should trump better representations or not.
That one is pretty simple. You have a Car object with four fields. The types of the fields are, respectively Optional<Make>, Optional<Model>, Optional<Year>, and Optional<Colour>.
Hickey makes it sound worse than it is.
so now when you have a function that takes in a Car object, you have no idea what fields those objects might have, because it's all optional! Which means the checks for the validity of each field end up spreading out to every function.
> so now when you have a function that takes in a Car object, you have no idea what fields those objects might have, because it's all optional!
Your types are already optional if you're adding constructors for each permutation of all input parameters.
Frankly, your contract was that you have no idea what fields those objects might have. I'm just fulfilling it. You won't have checks for validity of each field, as Optional is valid, but you will have to have code that handles Optional<> types (so things like foo.getModel().orElse()...), which is the requirement you described. That doesn't mean you'll be constantly checking the validity of each field.
This discussion sounds like there is confusion about the Car abstraction.
Make and model vs. makeId and modelId: Pick one. Are Make and Model referenced by Cars or not? There seems a slight risk of the Banana/Monkey/Jungle problem here, so maybe stick with ids, and then rely on functions that lookup makes and models given ids. I think it's workable either way.
As for all the optional stuff (color, year, ...): What exactly is the problem? If Cars don't always have all of these properties then it would be foolish of Car users to just do myCar.colour, for example. Test for presence of an optional property, or use something like Optional<T> (which amounts to a language supported testing for presence). Doesn't any solution work out pretty much the same? When I have had this problem, I have not done a proliferation of types (even in an inheritance hierarchy) -- that seems overly complicated and brittle.
I'm not familiar with Java. Does it have no notion of structural types at all? If it does, maybe you could wrap those fields in `Car` with `Maybe`/`Option` (I’m not sure what the equivalent is in Java) so you get something like `Car(Maybe Make, Maybe Model, Maybe Year, Maybe Colour)`?
Records are structural types. Null restricted types are in draft: https://openjdk.org/jeps/8303099
yes and it is called Optional (rather than Maybe)
I have thoroughly enjoyed that Hickey talk, but I think he has a very system-oriented view/take - which is very important and shows his experience - but it is also common to have control over the whole universe for our program.
In the interconnected system view, data schemas can change without notice, and the program should be backwards and forwards compatible to a reasonable degree to avoid being brittle.
This is not a problem when we control the whole universe.
I find that Haskell-esque type systems (strongly typed with frequent use of algebraic data types to represent every possible state in _that_ universe) work better for the latter, but are not the best fit for the former, and they often have to add some escape hatches at the boundaries.
Java itself is in a weird cross of this two - it has a reasonably strong type system nowadays, but it’s also a very dynamic runtime where one can easily create their own class at runtime and load it, reflect on it, etc.
So all in all — are you making that Car as part of your universe where you control everything, and it won’t change in unexpected ways? Make a record, potentially with nullable/Optional/Maybe types for the fields, if that makes sense.
If it represents some outside data that you don’t control, then you might only care about a subset of the fields: create a record type for that subset and use a converter from e.g. json to that record type, and the converter will save you from new fields. If everything is important then your best bet is basically what Clojure/JSONObject/etc do, just have a String-keyed map.
(Note: structural types can help here, and I believe OCaml has row polymorphism?)
> Python's lack of strong typing
I see people conflate strong/weak and static/dynamic quite often. Python is strong[1]/dynamic, with optional static typing through annotations and a type checker (mypy, pyright, etc).
Perhaps the easiest way to add static types to data is with pydantic. Here's an example of using pydantic to type-check data provided via an external yaml configuration file:
https://news.ycombinator.com/item?id=41508243
[1] strong/weak are not strictly defined, as compared to dynamic/static, but Python is absolutely on the strong end of the scale. You'll get a runtime TypeError if you try to add a number to a string, for example, compared to say JavaScript which will happily provide a typically meaningless "wat?"-style result.
In some significant ways, it's not strong at all. It's stronger than Javascript but it's difficult not to be. Python is a duck typing language for the most part.
Duck typing is an aspect of it being dynamically typed, not whether it is strong/weak. But strong/weak is not formally defined, so if duck typing disqualifies it for you, so be it.
https://langdev.stackexchange.com/questions/3741/how-are-str...
I always think of Python as having "fairly strong" typing, because you can override the type of objects by just assigning to __class__.
You're being pydantic =)
Living this dream in Python right now (inherited a code base that used nasty nesting of lists & dicts). You don't strictly need to do OOP to solve the problem, but it really does help to have a data model. Using dataclasses to map out the data structures makes the code so much more readible, and the support for type hints in Python is good enough that you can even debug problems with the type system.
> (...) by Python's lack of strong typing. In these situations, I often (...)
Python does support strong typing, albeit optional, with type annotations and tools like mypy.
If a problem is caused by the lack of strong typing, why not use strong typing?
Python now has type hints which can be used with an external type checker in the IDE. You'd probably type it with a class.
I recommend you use pydantic for type annotations. Alternatively, dataclasses. Then you pair it with typeguards @typechecked annotation and the types will be checked at runtime for each method/function. You can use mypy to check it at "compile time".
Having clear data types without oop is possible, even in python.
Python's not really built for that AFAIK, though. In languages built for it, you can type your dicts/hashes/maps/whatever and its easier to see what they are/know where the functions that operate on them live. I'm most familiar with Elixir which has structs which are simply specialized map (analogous to dict in Python) where their "type" is the name of the module they belong to. There can only be one struct per module, In this sense is easy to know exactly where its functions live and is almost like a class with the very key difference that modules are not stateful.
> In languages built for it, you can type your dicts/hashes/maps/whatever and its easier to see what they are/know where the functions that operate on them live.
I think I must be misunderstanding what you mean by that, because I can very much do that in Python.
Use Data Classes
>"In these situations, I often introduce objects that wrap the map or dict, and have methods that make sense for that level."
I've been doing the same thing since the end of the 80s as well starting with Turbo/Borland Pascal, C++, and later any other language that supports OOP.
Clojure has spec. That allows you to know a specification of what the data structure contains.
You can get strongly typed "shaped" data without objects[0], even in Java: Records[1].
~Unfortunately, I believe they're mutable (and cannot be made immutable).~ Edit: I was wrong, they're immutable.
[0]: I'm using "object" to mean "data bound to methods", since the concept of aggregate data in general long pre-date OOP (eg, C's structs)
[1]: https://docs.oracle.com/en/java/javase/17/language/records.h...
Java Records are immutable (by the most common definition). They don't have any means to update the record (via setters, etc.) after construction. That doesn't mean, for example, you can't store a reference to a mutable type (for example, a List or Map) in your record.
The frustration I have with Records is there is no good way to prevent direct construction of them. That is, the constructor is public, which prevents an easy way of enforcing an invariant during construction.
For example, let's say that you have a record with a Date type. There's no good way to prevent a user from creating the record with an invalid date, one that is out of a needed date range. Or maybe enforcing a field cannot be null or some combination of fields must meet requirements as a group.
The benefit I get from the classic Builder pattern is defeated with Records. I can't enforce checking of my fields before the construction of the record object itself. Presumably I would need to verify the object after construction, which is unfortunate.
You can enforce some invariants during construction:
record Point(int x, int y) {
Point {
if (x < 0) throw new IllegalArgumentException()
}
}
record Person(String name) {
Person {
requireNonNull(name);
}
}As mentioned by the other commenters, you should be able to run any validations or transformations on the data that you want in the canonical constructor, including re-assigning values (for example we've done defaults with `foo != null ? foo : new DefaultFoo()`). The only thing I think you can't do with a record is make the canonical constructor private and force users of your type to call factory methods that can return null instead of throwing an exception. You can provide those factory methods, but anyone can still call the constructor, so you have to do your hard checks in the constructor. On the other hand, no matter how many alternate constructors or factory methods you make, you're also guaranteed that every one of them eventually has to call the canonical constructor, so you don't need to spread your validation around either.
You can create dedicated, already verified objects to pass on to your record. E.g. AllowedDate (extends Date).
Can you make the Record class private to a module, and only export a static function that constructs them?
(I know very little about Java)
To a degree, yes, that’s possible. But leaking a private type over module boundaries is bad form, so a better (though possibly over engineered solution) would be to have a separate public interface, implemented by the private record type, and the static function would have that interface as return type.
Why is it bad form to expose a record type only via custom functions and not its field accessors? Isn't this just like exposing a more usual object with its public functions and private functions remain inaccessible?
A record's fields are final, so records are immutable (though they can include immutable pointers to mutable objects)
Thanks for the kind words :)
>learning that this is a labor of love
I underestimated both the amount of labor and the amount of love that would be involved. There were more than a few "throw everything out and start over" events along the way to this milestone.
Clojure definitely had a huge impact on how I think about software. Similarly, Haskell and Idris have rearranged my brain. However, I still let Java be Java. The humble object is really tough to beat for managing many kinds of runtime concerns. The book advocates for strongly typed data and leveraging the type system as a tool for thinking.
>Java's recent innovations certainly make this a lot easier
Yeah, it's an exciting time! Java has evolved so much. Algebraic types, pattern matching, `with` expressions -- all kinds of goodies for dealing with data.
How have you dealt with the current situation in Java where several new and important language features are still "preview" and are subject to being withdrawn? The possibility that these features might ultimately disappear is not theoretical: String Templates has been removed[1] from 23 as what would have been the "third preview," for example.
The (likely debatable) list of features in 23 that a.) remain preview/incubator and b.) appear relevant to a work on data oriented Java programming are:
Primitive Types in Patterns, instanceof, and switch (Preview) – JEP 455
Implicitly Declared Classes and Instance Main Methods (Third Preview) – JEP 477
Flexible Constructor Bodies (Second Preview) – JEP 482
Vector API (Eighth Incubator) - JEP 469
Scoped Values (Third Preview) – JEP 481
I've thought a lot about this quite a bit. In my day to day life, which is a cog in the machine at $Megacorp, I regularly work on embarrassingly old versions of Java (hello JDK 8!). So, not having the latest and greatest language features is a topic close to my heart. As such, the book takes a very tool agnostic approach. If we cover something that's only available advanced JDKs, we also cover what to do if you don't have it.
Data oriented programming is about building around the data in your domain. The latest tools are nice, but they're just tools.
I appreciate your conundrum. While it has been good to see Java language designers attempt to advance the language, they've been extremely conservative and non-committal. This is a problem because tooling is costly to develop and tool developers are forever facing the problem of whether to invest the work needed to integrate these language features when they take years to be realized, and may yet vanish. Likewise for authors, such as yourself.
I can't say I'm completely on top of the Java world, but I think the String Templates are one of the very few preview features that have been actually withdrawn and removed, right? Are there others?
I know some drift a bit on their implementations over time, but have not be wholesale yanked out.
Obviously the solution to this is to not rely on these preview functions for production code. The way to do that is to run production in an LTS version of Java. I don't think that's an extreme point of view, frankly.
The new stuff is interesting and cool, and in time, it ends up in the LTS version.
Having lived through Java 5, 6, and 8, these are halcyon times for Java. It's moving VERY fast, and has been for some time.
Are there preview capabilities in the LTS versions? Yes, there are. But they're not under the LTS tent. Don't use them. The demarcation between the development releases and the LTS releases are a smart program to get features out into the world, and set some real lines in the sand for advancement. It helps keep preview items from staying in preview mode for an indeterminate amount of time.
And the two year LTS release cycle for a notoriously conservative eco-system is ample.
> Are there others?
String Literals (JEP 326) made it to preview and got pulled.
> I don't think that's an extreme point of view, frankly.
Can't see where I suggested otherwise. I just wondered how the author was handling all the "in-flight" (An OpenJDK term there, not mine) features that Java currently has outstanding.
> It's moving VERY fast, and has been for some time.
They've been fast at creating new preview features. Actually landing finalized features though? In my view they're taking too long. When I compare Java and Python in this respect -- and I do as a working programmer in both on a frequent basis -- Java is still slow.
> When I compare Java and Python in this respect -- and I do as a working programmer in both on a frequent basis -- Java is still slow.
I feel this as well, but I also think it's desirable. Java is slower to add features because the bar is quite a bit higher (especially with regard to backwards-compatibility).
I'd much rather have long previews and occasional removal of previews than have a language that becomes bloated and kneecapped by past rushed decisions.
There's Kotlin, Scala, Groovy, etc, if you want to run on the JVM with languages that offer more features (and footguns). I find the balance OK, personally.
I'd much rather them pull the `STR.` templates than push it forward knowing its not ergonomic in practice.
String Literals have been superseded by Text Blocks though, so it’s only “got pulled” as a technicality, Text Blocks are stable parts of the language now forever. I believe something similar will happen with string templates.
Also, Java has gotten an insane number of new, significant features in the last couple of years — loom, algebraic data types, pattern matching, ZGC.. I don’t want to disrespect Python, but I really don’t think they have done anything to this degree.
Manning is a good quality publication (unlike Packt). Congrats. Looking forward. Will this be available on Safari books O'Reilly portal?
Technical Editor: Brian Goetz - you have my attention...
It has been awesome working with him.
There are few things as intimidating as having the Java language architect review your book on Java (haha). It's a much, much better book thanks to his involvement.
Manning let me conduct an interview with Brian a few years ago for my book with them. Here is the transcript: https://freecontent.manning.com/interview-with-brian-goetz/
He was very generous with his time and there are some good insights there for aspiring developers, as well as some info about the evolution of Java which may be relevant to the more data-oriented features that have been added in recent times.
After reading Brian's post[1] on data oriented programming years ago, I look forward for more on the subject using Java.
[1]: https://www.infoq.com/articles/data-oriented-programming-jav...
For people who're not aware: "Brian Goetz is a Java Language Architect at Oracle." (from the linked page.)
While I'm normally not a fan of appeal to authority, knowing this is what moves this from "will try to remember to check this out when I wake tomorrow" (it's 23:04 here) to "will definitely check out tomorrow".
Also it being from Manning helps. It's difficult to find good books today, so easy to self publish or get reeled in by some paper mill that banks on people wanting to have a book on their resume. So have to have something to filter out signal in the noise.
Congratulations! consider posting about in https://www.reddit.com/r/java/ it is a very active java community.
Will do!
Congratulations! In case people are looking for other modern Java books, here's one I'm working for building modern web apps in Java:
https://frequal.com/Flavour/book.html
It describes how to make single-page apps in Java, using the Flavour framework. No plugins, no extensions, and 99.9% pure Java. Plenty of sample code and links to relevant podcast episodes and demos.
Ok, I'll bite: why Subversion in 2024? https://sourceforge.net/p/flavour/trunk/HEAD/tree/
> TeaVMFan
Ah, that explains a lot of the questions I had about "modern webapps in Java." Relevant: https://news.ycombinator.com/item?id=25978053 (TeaVM: Build Fast, Modern Web Apps in Java; Jan 2021)
Although I would, sincerely, enjoy hearing what KotlinJS doesn't do that made you want to roll your own framework?
Flavour supports multiple JVM languages. Plus it is a batteries-included framework, no need to look to extensions to get routing, templates, EL, JAX-RS support, and more.
First up, congrats on getting over the hump — I struggle to complete a blog post, so I very much appreciate the effort it takes to do this!
A confusing sentence I noticed in the first chapter:
> ...then the only thing cost was some time, if they do it wrong, the cost is usually a bug.
I am guessing you mean "only cost was some time" (without the "thing")?
As for the topic, my hypothesis is slightly different — adopting functional approach to programming — even in imperative languages — leads you to the best patterns (or as you put it, "makes it inevitable") when combined with "evolutionary" architecture, and DoP is certainly one of them.
However, for a majority of software, in my experience, data "attributes" are really "leaf nodes", only to be consumed for display, and types do not really matter much there (eg. I don't mind `firstName` being a simple string). What we want to get right is types we do operations on, and most critically, relations between different data models. Accepting "evolutionary" principles in architecture also means that you welcome change and build for it, so getting any definition of data right from start is not an imperative.
But the topic certainly seems intriguing, so I look forward to learning more from your book and seeing how you apply it in a more imperative/OO way and what language features you found critical to success there.
Congrats again and good luck!
Another typo:
> ...no bad states to defend again.
Defend "against", I guess?
Oof -- embarrassing! At least I know what I'll be thinking about as I try to fall asleep tonight.
Thanks for pointing out the typos and wonky wording! Will fix!
As someone who loves Typescript, the first chapter of your book deeply resonated with me. Good data representations and data types that encode meaning can eliminate entire classes of bugs by making invalid states unrepresentable, and I wish more languages emphasized and supported these principles.
Congratulations! It's so interesting to witness how "techniques of the past" make a grand return in "new" programming languages that "gained" features from 4 to 7 decades ago to support this programming style. "records, pattern matching, `with` expressions, sum and product types" - in my upbringing, this stuff is decidedly "old-school FP". People going through their learning curve 30 years later than I have will see what I had learned as "dead, possibly failed-forever FP ideas" as the "we tried a lot of stuff but this seemed to be the best way to do it after all" of their time.
So Java took to up 30 years to mimic Common Lisp? Ok, CL took almost 20 to get a proper non-propietary GUI (not LispWorks/Allegro) close to SWING (MCCLIM), for AWT something like LTK was mostly enough.
I've read the first chapter and I like it a lot. I find myself way to often hiding business logic as in your first example. Also, showing how to use Java for DoP and combining it with other concepts like OOP encapsulation is very helpful IMO.
Now I'm waiting for two things:
1. Manning allowing me to grab it (forgot password email notifications seems to hang)
2. More chapters :-) ... no, really, just let it roll. Don't rush.
Can't wait to read this.
There's another book by a similar title
https://www.manning.com/books/data-oriented-programming
Care to elaborate how yours is different?
Sure! The core dividing line between the two books boils down to how they approach representing data in a program. Yehonathan's book advocates for immutable data stored in untyped data structures (for instance, Map<Object, Object>). My book takes the opposite approach. It advocates for building around immutable data that's strongly statically typed. It aims to capture the stuff in our domain using algebraic data structures.
This modeling difference has pretty far reaching implications. They lead to very different kinds of code bases, and thus very different books.
Here are the repos for the two books. Poking around those should give you a good overview for how radically two things both called "data-oriented" can differ :)
* https://github.com/chriskiehl/Data-Oriented-Programming-In-J... * https://github.com/viebel/data-oriented-programming
Congrats on your accomplishments!
I had two friends who both wrote separate books on JS. One early book on Angular and the other was about jQuery. Both had a hard time with the critical reviews they received on Amazon and it really dissuaded them from doing any more technical writing.
I love your approach and hope you keep writing and don't let the trolls get to you! Our industry needs more people who have this "soup to nuts" approach and take into account how nearly every language has changed dramatically over time.
Again, congrats and keep writing.
Congrats on writing and completing a book! I was involved in a few myself long ago, when I had the time available to contribute to those endeavors. In a world that often measures "the juice being worth the squeeze", I'm not sure authoring technical manuals would ever meet the criteria.
One of my personal photos I keep around was taken long ago in what was the biggest bricks/mortar bookseller. I was looking at the selection of books on Java available at the time. O'Reilly was the dominant publisher, and thus had several offerings on the wall. Most of the books were at least 2 inches thick. (If you were ever involved with writing a technical book in the early 2000s, you'll understand the publisher metrics at the time were based on the width of the spine on the shelf.)
Among the many Java manuals of significant girth was a small, THIN book with the title "Java -- the Good Parts". :-{}
Congratulations! I bought it and looking forward to the completed book.
The first chapter is pretty nice. Record types, switch statements and other new features will hopefully push Java programmers to think in terms of types more often.
Congratulations!
I see that the book is incomplete. I didn't know that early access for books was a thing, very neat. It might be pertinent to note in your post that it's still being written, with an estimated release window of Spring 2025.
I'm very much a "consume it when it's ready" person, so I'll keep this on my watch list.
I wonder whether it's the editing which is still in progress, or also the writing? The publication date seems very close if it's still being written.
(edit-clarity)
Writing is still in progress :)
No firm date for the final publication yet.
Is java still popular? Though I'm not a big fan of it I wouldn't mind using, but I'm after somewhat recent changes in licensing I'm not even sure I can. I don't fully understand the changes and I'm afraid of oracle coming after me :).
Can anyone explain current caveats and/or limitations with current licensing?
Perhaps, but probably don't attract many users like it used to be. For backend, some switched to Go. And on Android, some already switched to Kotlin.
>Can anyone explain current caveats and/or limitations with current licensing?
You can pretty much ignore the FUD posts about Java licensing. There are long winded replies to why it is FUD, but the short answer is it is trivially not a problem. It only applies if you use the Oracle JDK and want a certain type of support. Most of the world doesn't, instead using one of the other free JDKs.
Java is *not* popular in the reddit, HN, etc memesphere. In the real world it remains incredibly popular and a huge number of organisations continue to pick it as their language of choice for back-end development.
Java is more open than ever. Those random “scary” bullshit posts appear here and there but — OpenJDK is the standard reference implementation, and it has the same license as the Linux kernel. Different vendors give you builds of this same source, with some patches here and there, and they might provide support for their versions. One of these vendors is Oracle, who gives away the freemium OracleJDK. The latest LTS release is free to use with support, until the next one comes along, plus one year. But you would read more about different support services if you would need that - the same stuff is available for linux. In general, you can use any of these builds interchangeably, it doesn’t really matter. Like, intellij will offer you to download basically any of them.
So yeah, Java is insanely popular (top 3 language, among JS and Python, only their orders change depending on sane metrics (not you tiobe)), and is completely free with multiple vendors. Also, it’s pretty bullshit to consider Oracle any worse than other companies - they are the ones who completely opensourced OpenJDK and are responsible for 95+% of all the commits.
Congrats on launching the early access! I'm familiar with data-oriented programming from Clojure and F#, and I'm interested in seeing how you approach it in Java, so I just picked up a copy (ebook). Wish you all the best on completing the book!
Do you have some F# examples of data orientated programming>? It seems to mean a lot of different things to different people.
I can highly recommend excellent Domain Modeling Made Functional by Scott Wlaschin for an F# book that touches on a lot of the ideas which back data-oriented programming (namely, representing your domain as strongly typed data).
Congratulations! I bought a copy. If I like it I might recommend it as further reading for the university java course I teach. :)
PS. All the best with the yacht! xD
I now see these threads with a language in the title as kind of a digital (literally) version of a voluntary committal. Those herein are, of their own volition, taking their thoughts and feelings about technology X out of the Internet at large and into a safe place where they can do no harm. No one in threads such as these are going to change their mind. It's a beautiful thing.
Congrats and keep going! I ultimately failed at mine because I didn't keep disciplined focus on it when life got in the way. It was many lessons learnt.
https://www.amazon.com/Hands-Django-Beyond-Brandon-2016-03-2...
Purchased! I know very little about programming still, but Java is a language I have dealt with and will likely continue to have to deal with for the rest of my career, so here we go!
Unable to checkout. Keep getting an. error
congrats. Data Oriented Programming is cool, but you can easily get lost in the complexity of certain things.
there's another related book from one person active in the Clojure ecosystem. Though the book examples are in JS.
also, thank you for taking the step forward on doing your own small part in changing the 'AbstractFactory' thinking that's pervasive in the Java world.
For anyone interested, I think this is book you're talking about
Does it include any content related to algebraic data types?
It does! Chapter 4 specifically tackles modeling with sum and product types. They're used all throughout the book after that.
Nice, thanks! The website suggests that the book will be published next spring. I'll be sure to preorder the print version.
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The link is returning 404 for me.
How does DoP compare to Domain Driven Design (DDD)?
As someone coming from gaming, somehow early-access for books seems weird