Ask HN: Is Unified Modeling Language (UML) still a thing these days?

#1

Post by cbrgm » Wed, Sep 21, 2022, 3:27 PM UTC

I spent many years at university and was always confronted with UML diagrams. My professors and teachers were always quite conservative and we often had to draw UML diagrams (class diagrams, component diagrams, sequence diagrams, etc. ...) for every program we wrote or architecture we designed.

In the last jobs I worked, this was somehow never a thing. I don't mean that there was no documentation at all regarding the given software architecture or components and interfaces, but if there was, it was rather informal. If there were diagrams, then loosely drawn with draw.io or some icons and arrows that are supposed to somehow represent the services and relationships from various cloud providers.

Therefore my question is: Is UML still a thing nowadays or is it just too formal? Is it used in your current job?

Re: Ask HN: Is Unified Modeling Language (UML) still a thing these days?

#2

Post by pid-1 » Wed, Sep 21, 2022, 3:35 PM UTC

Before reading this post I didn't even remember UML existed.

Re: Ask HN: Is Unified Modeling Language (UML) still a thing these days?

#3

Post by cratermoon » Wed, Sep 21, 2022, 3:39 PM UTC

This is based on my experience across a variety of startups and small internet-focused companies. YMMV.

Some UML diagrams are useful, but only a small subset of the entirety of UML, and never very formally. Sequence diagrams and class diagrams are especially common. Also, UML officially is very specific about the details of each diagram, but rarely do the details matter very much. The subset supported by PlantUML seems to be plenty. Some of the diagram

Get a copy of Fowler & Scott's UML Distilled and that's as much as you'll ever need to know.

Re: Ask HN: Is Unified Modeling Language (UML) still a thing these days?

#4

Post by PaulHoule » Wed, Sep 21, 2022, 3:57 PM UTC

I am a volunteer working on the ISO 20022 standard and we use Ecore, an object modelling system that was designed to bootstrap UML, to represent financial messages.

I developed a toolset for working with Ecore that was adequate for what I needed to do. I took a crack at bootstrapping UML 2 but I found there were "chicken an egg" problems that I figured would take me a month to resolve, probably some important objects would have to be duplicated but then hidden from the upper layers.

(Resolving "chicken and egg" problems is something I do very well but I've been burned by spending a month working on something I felt uniquely inspired to do and then spending much more than a month trying to sell it and finding nobody gives a damn.)

UML has a fascinating vision which parallels the W3C's vision of the the semantic web, particularly "executable UML" ought to be possible, but it is held back by vendors who thrive on almost-functional standards that require proprietary additions to really work.

Re: Ask HN: Is Unified Modeling Language (UML) still a thing these days?

#5

Post by _tom_ » Wed, Sep 21, 2022, 4:33 PM UTC

It is almost never used. People draw occasional diagrams, but that's it.

Re: Ask HN: Is Unified Modeling Language (UML) still a thing these days?

#6

Post by olddustytrail » Wed, Sep 21, 2022, 4:44 PM UTC

Still used for solving mazes I believe: https://youtu.be/v2uAipnt2nw

Re: Ask HN: Is Unified Modeling Language (UML) still a thing these days?

#7

Post by none_to_remain » Wed, Sep 21, 2022, 4:59 PM UTC

A few weeks back I had occasion to read some SCTE (cable TV + descendents) signalling specifications, and I was tickled because they used enough UML that I had to actually go look up what the different arrows meant.

Other than that, don't think I've seen formal UML, just informal diagrams with boxes, arrows, and icons.

Re: Ask HN: Is Unified Modeling Language (UML) still a thing these days?

#8

Post by quux » Wed, Sep 21, 2022, 5:12 PM UTC

The only UML diagram that seems to survive is sequence diagrams, which are actually very useful and well designed

Re: Ask HN: Is Unified Modeling Language (UML) still a thing these days?

#9

Post by pydry » Wed, Sep 21, 2022, 5:22 PM UTC

UML's problem is not really that it's too formal but that it's usually too detailed, too vague or too out of sync with the real system to be useful.

It was also heavily associated with Big Design Up Front, which has been more or less trashed in favor of agile / iterative improvements / spikes / whatever you want to call it.

PlantUML still seems to be a thing, although perhaps more for general diagramming.

Re: Ask HN: Is Unified Modeling Language (UML) still a thing these days?

#10

Post by ReflectedImage » Wed, Sep 21, 2022, 5:33 PM UTC

The research group I was in when I did my PhD focused on modelling. This was 7 years ago and back then UML was considered to be dead. It's all moved on to Domain Specific Modelling Languages (DSMLs). Who's using DSMLs you might ask? Your car manufacturer is using them for writing the software for your engine. They draw out a diagram and both the code and safety cases they need to submit to the regulators are auto generated.