Comment by OliverJones | Hacker News Reader

Comment by OliverJones | Hacker News Reader

Some random observations from an old-timer developer.

1. This excellent article is all about UML's class modeling capabilities. UML has other useful capabilities.

2. Sequence diagrams are very useful. I've created plenty to document and teach complex interactions between various (micro-) services. But it simply never occurred to me that I would generate code from sequence diagrams. They're simply a way to capture and refine the stuff on a whiteboard.

3. The data-modeling tools supporting logical and physical models suffered from some of the same needless complexity as the attempts to codegen from UML. And from the ludicrous expense of the tools. Every place I worked had at most one license for those tools.

5. The code-navigation and code-completion features in modern IDEs implement some of the best parts of the UML codegen vision. Tell VS that a class implements a particular interface, and it offers to generate a skeleton of the necessary methods for you. Great. Look at a method declaration, and see at a glance that it's from a superclass. Also great.

6. I hope somebody, maybe the author, collects articles like this for a text to be used in software engineering teaching. Our trade needs some serious mid-career training. The military has the Army War College. We need the Software Wars College, to get a chance to think this stuff through.

7. PlantUML is a pretty good way of embedding UML in wikis and other online docs. "Pretty good" is good enough for most purposes.

I love sequence diagrams. They are essential for designing complex event-driven system where there are a lot of asynchronous operations. I often use them to make sense of and/or prevent race conditions.

I can also see the value in UML class diagrams for complex OOP systems but for me personally, I can make do without them in the vast majority of cases. They are not as valuable to me as sequence diagrams.

I never liked UML but I agree time-sequence diagrams can be very helpful.

I still willingly make sequence diagrams to fully document what is happening in a complex system or architecture. I find them to be very useful to get everybody on the same page for the "order of events".

The class diagrams were something I was taught heavily in college and haven't really used since then. Feels like it's just as easy to write down "this object has a one-to-many relationship to this object"

+1

Sequence diagrams force you to think about the flow of control in a system.

When reviewing draft designs, I sometimes ask the author to convert a simple boxes-and-lines architecture diagram to a sequence diagram. It can be revealing.

I can relate. It's an essential communication tool. When discussing asynchronous events with a colleague, there is a point in the discussion when it becomes almost impossible to explain it in words and you really need something like a sequence diagram to communicate accurately.

> 2. Sequence diagrams are very useful. I've created plenty to document and teach complex interactions between various (micro-) services.

I've always used the classic "bus timing diagram"[0] style of sequence diagramming. It's limited, but an excellent way to illustrate a parallel sequence.

[0] https://study.com/academy/lesson/bus-timing-diagrams-definit...

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