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Sequence diagrams, the only good thing UML brought to software development

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Re: Sequence diagrams, the only good thing UML brought to software development

#261

Post by zitterbewegung »

dahwolf wrote: post #158

In some ways, software development practices have degraded since that era. It largely has to do with the need for speed which comes at the expense of careful consideration, quality, integrity and the formal standards that support it. In fact, I believe it pretty much killed the profession of software architect. Many teams had it as a dedicated role, and this indeed would be a person documenting/designing systems usin…

Sequence diagrams and state machines should be probably taught much better in CS courses. You generally see state machines in a theoretical course and things like sequence diagrams in an object oriented course.

What we should do is probably in your advanced data structure programming course that everyone has to take is to create a model of an elevator and diagram the behavior using a sequence diagrams. This would be achieved by using an associative array AKA a map [1] that would represent where the elevator is and what it has to do next (current state and next state based on input).

If you program this correctly it gets around using unit testing even because you have diagramed and all parts of the system are known and can just be gone through and that would be a sufficient test. An example of a library that implements this is at https://pypi.org/project/python-statemachine/

[1] https://en.wikipedia.org/wiki/Associative_array

Re: Sequence diagrams, the only good thing UML brought to software development

#262

Post by rukuu001 »

dahwolf wrote: post #158

In some ways, software development practices have degraded since that era. It largely has to do with the need for speed which comes at the expense of careful consideration, quality, integrity and the formal standards that support it. In fact, I believe it pretty much killed the profession of software architect. Many teams had it as a dedicated role, and this indeed would be a person documenting/designing systems usin…

I think the industry is diverging.

- There's very high-level engineering occurring ('computer science'). I always assumed this would be at places with 'web-scale' problems, but I've been seeing amazing work in local (not-web-scale) product companies here in Australia.

- On the other hand, I think a lot of other development work is not much above building flat-pack furniture. I guess this is where lo/no-code solutions will thrive

The important thing is to recognise which is being done, and which practices apply each case.

Re: Sequence diagrams, the only good thing UML brought to software development

#264

Post by calf »

michaelsbradley wrote: post #130

Statecharts[1] predate UML, and became part of UML[2]. From the time of their invention to the present, people have devised systems for serializing (i.e. as data structures and code) statecharts and translating them to (or interpreting them as) executable programs[3]. While they may not be all the rage and take some discipline to learn and use effectively (what software tool/concept doesn't?), they can be a valuable…

I was asked to read Harel's paper as part of my thesis, I personally think this stuff is wonderful and foundational to computer science and computer engineering, researching issues like concurrency and system complexity. But I can see how industry programmers would find little direct use for it.

Re: Sequence diagrams, the only good thing UML brought to software development

#265

Post by nobodyandproud »

UML as a 4GL and coding the “important parts” died and I’m glad for it.

Turning visualizations and encoding all interfaces and interactions made things cryptic.

Using diagrams sparsely to explain the main design ideas visually? Absolutely.

Re: Sequence diagrams, the only good thing UML brought to software development

#266

Post by wpietri »

dahwolf wrote: post #158

In some ways, software development practices have degraded since that era. It largely has to do with the need for speed which comes at the expense of careful consideration, quality, integrity and the formal standards that support it. In fact, I believe it pretty much killed the profession of software architect. Many teams had it as a dedicated role, and this indeed would be a person documenting/designing systems usin…

> In fact, I believe it pretty much killed the profession of software architect.

And thank goodness. I am all in favor of more consideration, more quality, more integrity. I like good architecture. But I think it's a giant mistake to create a software architect role. Every company where I saw that in practice, the average architect was a bloviator who did no actual work but was very excited to tell everybody else how to work.

At the code level, this resulted in a lot of messes. The edicts and white papers sounded good in theory to the kind of people who decided the bonuses of the architects. But frequently they were unworkable in practice, causing a lot of code that conformed to the theory but was a pain to actually deal with.

I agree with you that a lot of things are half-assed and rushed, of course. But we are never going back to a world of 18-36 month release cycles where people could stroke their chins for a quarter or two before building anything. Instead, we need to move in the direction of continually investing in quality, so that the design of systems improves over time. Something that I think is actually easier, in that waterfall design practices locked in important decisions early on, when people knew the least.

Re: Sequence diagrams, the only good thing UML brought to software development

#267

Post by bluGill »

lesuorac wrote: post #124
imiric wrote: post #31

I also find sequence diagrams to be the most useful, but disagree that the rest of UML is useless. Class, component, package, activity and state machine diagrams are all useful ways to model the structure and behavior of a system visually. The only reason the other diagram types fell out of favor is because of the development methodology change starting in the early 2000s. The industry started rejecting Waterfall, ea…

> The only reason the other diagram types fell out of favor is because of the development methodology change starting in the early 2000s. The industry started rejecting Waterfall, early design and system architects, in favor of Agile, just-in-time design and empowering developers. I dunno, whenever I heard people say they're doing Agile all I see is them doing Waterfall without documentation.

How is that worse than waterfall with outdated documentation which is what we had before.

Re: Sequence diagrams, the only good thing UML brought to software development

#268

Post by klabb3 »

yafbum wrote: post #198
dahwolf wrote: post #158

In some ways, software development practices have degraded since that era. It largely has to do with the need for speed which comes at the expense of careful consideration, quality, integrity and the formal standards that support it. In fact, I believe it pretty much killed the profession of software architect. Many teams had it as a dedicated role, and this indeed would be a person documenting/designing systems usin…

We haven't told ourselves that shipping garbage in short cycles is the only way to do things. The market has pretty much determined that companies that over invest in formal software design activities lose out competitively in the long run, and the survivors are the ones with the right balance. You're welcome to prove the market wrong.

> The market has pretty much determined that companies that over invest in formal software design activities lose out competitively in the long run

The same market that gave us AT&T, Comcast, DRMed IoT Juice presses, FTX, Enron, and so on? Not sure it’s wise to conclude that the market produces optimal solutions, or even incrementally better solutions than yesterday. Especially in domains with extremely long feedback cycles, like organizational trends.

I DO think there is some hocus pocus market zeitgeist that does something resembling gradient descent, but it’s acting over very long cycles and there’s a ton of room for cargo culting, grifting, and opportunistic grabs along the way. Heck, marketing is an entire field dedicated to affecting “rational actors” in the marketplace.

Re: Sequence diagrams, the only good thing UML brought to software development

#269

Post by [deleted] »

dahwolf wrote: post #158

In some ways, software development practices have degraded since that era. It largely has to do with the need for speed which comes at the expense of careful consideration, quality, integrity and the formal standards that support it. In fact, I believe it pretty much killed the profession of software architect. Many teams had it as a dedicated role, and this indeed would be a person documenting/designing systems usin…

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