What happened to UML? I remember it was everywhere in enterprise computing 20 years ago but seems to have disappeared now.
Is it still around or did it go the way of SOAP, Java Applets? If not, what has replaced it?
What happened to UML? I remember it was everywhere in enterprise computing 20 years ago but seems to have disappeared now.
Is it still around or did it go the way of SOAP, Java Applets? If not, what has replaced it?
Underneath the good ideas of UML was the idea of model driven development - that you could generate code from the models.
Good diagrams are an art form though, just like other forms of good documentation. There is a big difference between a diagram being a normative source of truth, and being a good tool.
Take this diagram as an example: https://takaakit.github.io/uml-diagram-for-ddd-example-in-ev...
* Nearly the top half is taken up by relations which aren't especially helpful, and would be better expressed on the entities themselves.
* The "Location" type looks like the primary type in the system based on nearly half the types in the system connecting with it, creating a nest of graph edges. However, this is likely a simple and immutable record type. If the entities in this diagram had attributes (e.g. like a class diagram), you could refer to it by name, and greatly simplify the cognitive load in understanding this picture.
This is the sort of diagram that gets generated from code, and is at the level of specificity needed to generate code from a diagram. It also isn't very useful for using the model to convey the system to a person - a developer might be more comfortable reading the code rather than looking at a picture generated from it.
IMHO, that split focus in UML between people and tooling greatly reduced the overall usefulness and understanding of the system. It gave UML a bad reputation. Training on MDD tools prevailed over providing a baseline of common nomenclature to enable "team cave drawing on a whiteboard", which has no commercial tooling or market other than the whiteboard and markers.
The areas where visual languages have a bit more prevalence are on the business modeling side, including things like network architecture diagrams.
It is a bit of a shame - going through a set of use cases while iteratively improving the architecture by improving a set of class, sequence and ECB diagrams is something I always found to be crazy efficient vs diving immediately down to prototype code.
It's still being taught in schools AFAIK.
Had an intern a year ago whose school forced them to go the whole nine yards with UML. Our company gave them a project to build, and their school made them draw use-case diagrams, class diagrams, sequence diagrams, and activity diagrams, before the student was allowed to write any code.
This was a waste of everyone's time, and we gave the school some choice feedback which I'm sure they'll ignore.
Sequence diagrams are still used quite a lot, and for good reason, they're incredibly useful. I see simple class diagrams quite frequently as well, but without the poorly designed arrow nonsense (shaded? open? closed? argh!).
I'm kind of hazy about where the boundaries between bona fide UML and PlantUML are, but PlantUML is in pretty common use in my world - more for sequence diagrams and state diagrams than class diagrams though. Of course PlantUML has competition from things like Mermaid, but they're all much of a muchness.
My very non-scientific impression is that tools like Rational were mostly used for drawing class diagrams and ... that just turned out not to be that useful because the tooling didn't exist to round-trip changes in the code back into the diagrams meaning the diagrams lost parity with the code rather quickly. It was sort of useful in the linear design/code/deliver world, but we're a lot more iterative now.
I remember having to use Rational Rose back in the day, and I had to ask my boss why because the software crashed and the files got corrupted all of the time. If it didn’t help them write better software, why were we using it?
That said, I still find plantuml to be helpful, particularly for sequence and activity diagrams. With LLMs especially. Use dependency injection, fine granularity components, sequence and activity flows. At least for me, helps keep my mind organized. But, these days I work alone. I feel it may be too dated for the modern developer.
> With LLMs especially...
> I feel it may be too dated for the modern developer.
Sounds like you're still ahead of the curve, worry not.
I'm still too much of a curmudgeon to even give LLMs a try.
I just learned about UML earlier today when I wanted to bring in a mermaid flowchart into lucidchart. If you bring in mermaid using lucidchart, it makes it a raster image. But if you use UML markup, you can ungroup it and modify. I couldn’t get a good way to convert from mermaid to UML markup that lucidchart could handle. Ended up a dead end for me.
On a similar note I've had various annoyances with wanting to round trip diagrams from Mermaid or PlantUML into Miro and vice versa. There doesn't seem to be much out there to facilitate this, which is strange, because it feels like a very enterprisey thing to want to do.
There's probably a SaaS product in it for someone sufficiently interested in the topic... probably not at unicorn scale, but enough for a side income perhaps?
Just this week I did a bunch of UML diagrams.
It is pretty much alive in big corps.
I imagine it got out favour on hipster coffee shops coding their next big idea, rewriting multiple times, instead of validating their ideas in first place.
Github supports UML diagrams in their markdown for a reason.
I think folks upgraded to GML [0]
[0] https://wiki.c2.com/?GalacticModelingLanguage
I love it. Even with GML, you run into problems. Diagramming is an art more than a science. You have to know your audience (technical people, marketing types, investors, customers...)
Leaving stuff out is also important. (Example: Unless you're building a DNS related product, don't bother to include "DNS" in your diagrams. Your use of it is assumed.)
This is wonderful. Thank you.
Wait until you discover IGML (intergalactic modeling language)[1]. The entire user interface of a space game I'm working on -- including menus, buttons, sliders, even text rendering -- is literally implemented via a form of IGML. It's a very old language. Games like Asteroids and Battlezone have used it since forever.
[1] https://wiki.c2.com/?InterGalacticModelingLanguage
Just my opinion, but I think that folks realised it was not much use for initial design, but could work reasonably well for documentation of existing systems.
Documenting existing system dependencies using the product which which I'm a founder:
https://schematix.com/video/depmap
Like UML deployment diagrams, but our models are interactive and can be queried.
We also have a large customer doing DDD modeling and then generating code directly from the models they build.
Yeah, it started to work for documentation when they invented that thing that prevents you from having to constantly maintain super complex diagrams in order to keep them in sync with the actual product.
In payments and most other industries with a lot of connections to 3rd parties and complicated transactional flows, UML diagrams (especially sequence diagrams) are used a lot, albeit mostly as a conceptual tool rather than some formal description (see for example the Stripe docs). I also see UML state chart-like approaches being used more formally in frontend (e.g. XState).
IIRC it got a bit out of fashion towards the end of the 2000s along with the OOP fanatism it was closely related to.
UML as a methodology seems to have disappeared, but bits of it (e.g. sequence diagrams) seem to have been absorbed by the profession at large.
I think the UML statecharts are a much more useful diagrams than sequence diagrams. It can convey a lot more of the behaviour especially if you use the entire 'Harel' formalisms.
Too bad, they aren't that popular to document behaviour, because sequence diagrams really don't convey that much.
For example timeouts are very neatly described in a harel state chart. How will one describe timeout and timeout handling in sequence diagrams.
Sequence diagrams existed prior to UML. They were extensively used in telecom: “message sequence charts.”
They were part of a telecom language called SDL. There were tools to “compile” to various languages such as C. If you followed their rules, you were supposed to be able to go back and forth between C and SDL.
I only remember this because the biggest tool provider at that time was a French company called Verilog. They preceded the HDL by a few years, I guess.
I used to work for Motorola's telecom division and we used IBM Rational Suite to generate C++ classes from the SDL. Merges (and we used very long-lived release branches) were pure hell...
IIRC sequence diagrams were invented by one of Carl Hewitt’s PhD students during Hewitt’s earlyish work on the Actor model?
Gul Agha?
I occasionally use a “UML Lite,”[0] to illustrate stuff, but I seldom work at the scale that I would consider it necessary. I generally keep my designs in my head. Makes for much faster, and higher-quality work.
[0] https://littlegreenviper.com/the-curious-case-of-the-protoco...
My theory is that Agile killed it. UML requires a lot of planning up front, and in my unfortunate experience, any sort of planning is completely antithetical to Agile.
Experiencing this right now, zero planning for a re-write of a system
I think its abandonment is related to the adoption of agile methodologies. UML was used to describe systems from day one. Agile methodologies came in, claiming that we don’t need it.
You still need to describe systems in agile.
All agile does is ask you to iterate, which means updating your design, your code, and your tests & documentation, as you learn.
Please read the agile manifesto again, and actually apply it. It does not say we don’t do design at all. Never did.
There is the manifesto, and then how almost everyone does it.
We still learned UML diagrams in school in 2019, though I have to say I haven't used it anywhere in my job
In the case of UML, I think enterprise consulting and tool sales might've already obscured much of the real value of semiformal methods, before a CS curriculum could sour students on it.
With ZIRP growth scheme startups hopefully over, and more of us having to get jobs building systems that work reliably and sustainably, we might gain a new appreciation for system modeling.
UML never matched reality and this isn’t really an engineering discipline even if we pretend it is.
You can really break UML by specifying a system then changing it a number of times. That process will hurt you. Badly.
UML and waterfall/Big Requirements Up Front/analysis paralysis all ride in the same car.
Agile and scrum and iteration saw them off.
And that is how we end doing integration tests where folks in the field discover missing user stories that no one is going to implement, because there is no budget left.
Just another data point that the "low code/no code" revolution sputtered out over a decade ago.
I still see and use a small subset of UML for more complex architecture discussions, but that's about it (i.e. service nesting, message passing, etc.).
UML was a scam really. They took a lot of very useful diagrams and created a absolute behemoth of unproven system to develop software and sold it.
The diagrams are very nice and useful. But the UML as a process, if taken literally, it a total disaster.
One of the creators of UML, Booch, has said so himself that it was taken to a point where it should never have. Interesting interview: https://youtu.be/u7WaC429YcU?feature=shared
Thanks. I was only going to find the part about UML but I ended listening to the whole thing. What a legend!
> UML was a scam really.
Objectively and utterly wrong.