6 ms·

All You Need to Know About UML Diagrams

131 points by noelceta 8y ago

giseir 8y ago
UML Diagrams are actually quite useful, sometimes you just need a structured way to reason about software.
- bluGill 8y ago
  There are two types of useful UML: The first is what I call whiteboard UML - it looks like any UML course except you draw it on a whiteboard, snap a picture on your phone and start implementing it. A couple weeks latter you realize that the design has diverged from the whiteboard so you delete the pictures. The whiteboard was useful for those two weeks to get the discussion started. The second is maintained, preferably automated. If you use viseo that means an entire team who's only job is to police the code to ensure everybody updates as change happens. Lesson: don't use viseo, use a tool that either generates your code (in C like languages this would be the header files), or a tool that imports the actually code to create diagrams. In either case the reason you do this is because every week you print the diagram out on poster paper and hang it on the wall of your cube/office. (if you are in an open floor plan UML is useless because you don't have a wall to hang it on).
  - megaman22 8y ago
    I suppose in an open office you could use your UML diagram printouts to make a cubicle. After a half a year or so, if you keep pasting them up on top of each other, you might start getting some sound-proofing effects.
  - vram22 8y ago
    When UML was more popular at the height of the OO(AD) frenzy, there was a tool from Peter Coad's company called TogetherJ. IIRC it could do round-tripping between UML and Java code. I think I tried the tool out but not that feature. TogetherSoft was later acquired by Borland, as I remember.
    - blattimwind 8y ago
      In IntelliJ you can refactor from UML views.
      - vram22 8y ago
        Interesting, will check that out.
clstl 8y ago
neat, the pictures could be better doh
- noelceta 8y ago
  You are right, pictures should be better focused and more unified in style. Can you recommend any software?
  - clstl 8y ago
    I personally use https://draw.io https://draw.io
    - Born_Again 8y ago
      Draw.io is also great for working in groups.
  - paublyrne 8y ago
    https://www.gliffy.com https://www.gliffy.com is rather good.
  - alexott 8y ago
    PlantUML?
  - pieterr 8y ago
    http://plantuml.com/ http://plantuml.com/ allows you to describe your UML diagram in a dot-like language.
  - coldacid 8y ago
    PlantUML[1] is pretty decent, especially if you like keeping the contents of the diagram in easily-versioned text. [1]: http://plantuml.com/ http://plantuml.com/
  - bane 8y ago
    You can do an impressive amount of diagramming with the free yED. It also has some automatic layout tools and so on. It's also cross-platform so everybody can use it. The gallery has some impressive examples in it. https://www.yworks.com/products/yed https://www.yworks.com/products/yed
tilt_error 8y ago
You lost me at ”Visio”!
npendleton 8y ago
My favorite flavor, plantuml, available with a cheesy (but very convenient) cli wrapper via npm- https://www.npmjs.com/package/node-plantuml https://www.npmjs.com/package/node-plantuml The --unicode mode is particularly delightful
- wainstead 8y ago
  +1 for plantuml. You can make very useful sequence diagrams with it, in ascii no less.
  - _puk 8y ago
    It would be remiss at this point not to recommend websequencediagrams[0].. been using it for years (and convinced multiple workplaces to shell out for the self hosted version..). It's great :) 0: https://www.websequencediagrams.com/ https://www.websequencediagrams.com/
- vvanders 8y ago
  There's a VSCode plugin for plantuml, it's fantastic.
kyberias 8y ago
I don't think this article covers "all you need to know" particularly well.
bastijn 8y ago
“The relation between different classes (represented by a connecting line), makes up a class diagram.” Taken from class diagrams. Not everything you need to know it seems. It misses multiplicity at least. (Didn’t read/scan more) Also, did you really intend to have one-to-many for both client and account? Since you labeled owns. One client multiple accounts is ok for the sample. One account can have multiple owners (clients) in theory but for the introduction (audience is I guess the inexperienced) I would go with 1.
WillReplyfFood 8y ago
Missing a warning: You can get lost in here and start to programm in uml- which will result in alot of generated template code, in need to be fleshed out- or a attempt to integrate coding snippets into your uml editor of choice and the realization that the most accurate representation of systems- is actually sourcecode. The concept is never the full realization, and shouldnt become it.
htor 8y ago
aha, you almost got me there. keep your distance, uml. we shall not intermingle ever again...
- Eyght 8y ago
  I once took a couple of informatics courses at uni. They talked about uml as if the software would just magically fly out of the diagrams onto peoples computers.
kaushalmodi 8y ago
I have started using PlantUML[1] quite a bit recently in my blogging (one example[2]). I have PlantUML code in Org mode source blocks, and Org Babel then generates the svg/png of the diagram each time I update the code block. [1]: http://plantuml.com/ http://plantuml.com/ [2]: https://scripter.co/org-contribution-flowchart/#flow-chart https://scripter.co/org-contribution-flowchart/#flow-chart
bane 8y ago
Creating a bunch of UML diagrams up front is usually the sign of a broken software development process. However, there's a lot of great work that went into the various diagramming grammars that turn out to be really useful in different cases. I've found that spinning up UML-like diagrams for certain subsystems on a whiteboard, or quickly in yEd or similar tool helps immensely with: a) creating a "thing" to facilitate communication and understanding b) capturing a design after it's done as part of a deployment/hand-over package c) a useful toolkit for reverse engineering a system that you had dumped on you etc. basically, any sort of ad-hoc communication need or information capture process. Software Engineering coursework will warp your brain into thinking that you need to spend a few years in a spaceship in orbit around Saturn dreaming up millions of UML diagrams that when done, will magically barf out all of the code that makes up some enormous over-engineered enterprise fizzbuzz system. It takes a long time to overcome that nonsense without throwing away the goodness that exists here -- there's some excellent diagramming techniques that really help with coming up with a common understanding of how a system should work for a team and product owners and used well can bridge huge communication gaps. Many of the diagrams more or less show the same information, but with a slightly different angle that can help communication. The diagram grammars themselves can get really fussy and particular, but I think when they're used best only certain components of the grammars are used to fill very specific communication needs, the rest is more or less sketched in, and the remaining grammar can be pretty comfortably be left out. Many times, you can just invent a diagramming grammar that you can the other parties agree to and just "be inspired" by ideas from UML and get most of what you need done. There's also grammars that are not part of UML that would make sense for people to get familiar with. ArchiMate comes to mind as a particularly great example. I don't use it explicitly (the software tooling support for it is garbage, but you can fake it with yED pretty well), but I've used systems inspired by it numerous times to succinctly capture incredibly complex enterprise systems and data flow and tie those things to business processes and needs. https://en.wikipedia.org/wiki/ArchiMate https://en.wikipedia.org/wiki/ArchiMate
- diminoten 8y ago
  > Creating a bunch of UML diagrams up front is usually the sign of a broken software development process. Wait, what? Why? Assuming I'm doing them because they help me flesh out an idea, it should be fine, right? You're talking more about being forced to express a concept in UML when it's already adequately described in a non-UML format, right?
dry_flamingo 8y ago
http://www.nomnoml.com/ http://www.nomnoml.com/ is another good one. https://github.com/skanaar/nomnoml https://github.com/skanaar/nomnoml
seattle_spring 8y ago
> All You Need to Know About UML Diagrams Honestly thought it was just going to be a blank page.
GorgeRonde 8y ago
Some thoughts I've had on "graphical based programming" (if UML can be deemed as such): - Don't draw the product. Draw the organization that produces it. As per Conway's law, you'll be drawing the same thing in the end, but contrary to UML you won't face the problem of the representation of the product evolving faster than the ability of the organization to update it. The representation (the diagram) will just evolve as fast as the organization can represent itself. This require that: - The diagram is the organization and the fundamental aspect of code is UI. There is no distinction between the primitives of the UI/UX system (clicking on that, moving this item from here to there, etc ...) and its computational primitives. This is the tipping-point that: - a) makes this system homoiconic - b) makes this system homoschematic. Homoschematicity (same-representation/same-gesture in ancient Greek) is reached when the datastructure that is set in immediate relation to itself (typically lists in Lisp) is also what is directly presented to the end user and can be displayed as such, ie. immediately (lisp code is too ugly and limited for that).

131 points by noelceta 8y ago

giseir 8y ago

UML Diagrams are actually quite useful, sometimes you just need a structured way to reason about software.

bluGill 8y ago
There are two types of useful UML: The first is what I call whiteboard UML - it looks like any UML course except you draw it on a whiteboard, snap a picture on your phone and start implementing it. A couple weeks latter you realize that the design has diverged from the whiteboard so you delete the pictures. The whiteboard was useful for those two weeks to get the discussion started. The second is maintained, preferably automated. If you use viseo that means an entire team who's only job is to police the code to ensure everybody updates as change happens. Lesson: don't use viseo, use a tool that either generates your code (in C like languages this would be the header files), or a tool that imports the actually code to create diagrams. In either case the reason you do this is because every week you print the diagram out on poster paper and hang it on the wall of your cube/office. (if you are in an open floor plan UML is useless because you don't have a wall to hang it on).
- megaman22 8y ago
  I suppose in an open office you could use your UML diagram printouts to make a cubicle. After a half a year or so, if you keep pasting them up on top of each other, you might start getting some sound-proofing effects.
- vram22 8y ago
  When UML was more popular at the height of the OO(AD) frenzy, there was a tool from Peter Coad's company called TogetherJ. IIRC it could do round-tripping between UML and Java code. I think I tried the tool out but not that feature. TogetherSoft was later acquired by Borland, as I remember.
  - blattimwind 8y ago
    In IntelliJ you can refactor from UML views.
    - vram22 8y ago
      Interesting, will check that out.

clstl 8y ago

neat, the pictures could be better doh

noelceta 8y ago
You are right, pictures should be better focused and more unified in style. Can you recommend any software?
- clstl 8y ago
  I personally use https://draw.io https://draw.io
  - Born_Again 8y ago
    Draw.io is also great for working in groups.
- paublyrne 8y ago
  https://www.gliffy.com https://www.gliffy.com is rather good.
- alexott 8y ago
  PlantUML?
- pieterr 8y ago
  http://plantuml.com/ http://plantuml.com/ allows you to describe your UML diagram in a dot-like language.
- coldacid 8y ago
  PlantUML[1] is pretty decent, especially if you like keeping the contents of the diagram in easily-versioned text. [1]: http://plantuml.com/ http://plantuml.com/
- bane 8y ago
  You can do an impressive amount of diagramming with the free yED. It also has some automatic layout tools and so on. It's also cross-platform so everybody can use it. The gallery has some impressive examples in it. https://www.yworks.com/products/yed https://www.yworks.com/products/yed

tilt_error 8y ago

You lost me at ”Visio”!

npendleton 8y ago

My favorite flavor, plantuml, available with a cheesy (but very convenient) cli wrapper via npm- https://www.npmjs.com/package/node-plantuml https://www.npmjs.com/package/node-plantuml The --unicode mode is particularly delightful

wainstead 8y ago
+1 for plantuml. You can make very useful sequence diagrams with it, in ascii no less.
- _puk 8y ago
  It would be remiss at this point not to recommend websequencediagrams[0].. been using it for years (and convinced multiple workplaces to shell out for the self hosted version..). It's great :) 0: https://www.websequencediagrams.com/ https://www.websequencediagrams.com/
vvanders 8y ago
There's a VSCode plugin for plantuml, it's fantastic.

kyberias 8y ago

I don't think this article covers "all you need to know" particularly well.

bastijn 8y ago

“The relation between different classes (represented by a connecting line), makes up a class diagram.” Taken from class diagrams. Not everything you need to know it seems. It misses multiplicity at least. (Didn’t read/scan more) Also, did you really intend to have one-to-many for both client and account? Since you labeled owns. One client multiple accounts is ok for the sample. One account can have multiple owners (clients) in theory but for the introduction (audience is I guess the inexperienced) I would go with 1.

WillReplyfFood 8y ago

Missing a warning: You can get lost in here and start to programm in uml- which will result in alot of generated template code, in need to be fleshed out- or a attempt to integrate coding snippets into your uml editor of choice and the realization that the most accurate representation of systems- is actually sourcecode. The concept is never the full realization, and shouldnt become it.

htor 8y ago

aha, you almost got me there. keep your distance, uml. we shall not intermingle ever again...

Eyght 8y ago
I once took a couple of informatics courses at uni. They talked about uml as if the software would just magically fly out of the diagrams onto peoples computers.

kaushalmodi 8y ago

I have started using PlantUML[1] quite a bit recently in my blogging (one example[2]). I have PlantUML code in Org mode source blocks, and Org Babel then generates the svg/png of the diagram each time I update the code block. [1]: http://plantuml.com/ http://plantuml.com/ [2]: https://scripter.co/org-contribution-flowchart/#flow-chart https://scripter.co/org-contribution-flowchart/#flow-chart

bane 8y ago

Creating a bunch of UML diagrams up front is usually the sign of a broken software development process. However, there's a lot of great work that went into the various diagramming grammars that turn out to be really useful in different cases. I've found that spinning up UML-like diagrams for certain subsystems on a whiteboard, or quickly in yEd or similar tool helps immensely with: a) creating a "thing" to facilitate communication and understanding b) capturing a design after it's done as part of a deployment/hand-over package c) a useful toolkit for reverse engineering a system that you had dumped on you etc. basically, any sort of ad-hoc communication need or information capture process. Software Engineering coursework will warp your brain into thinking that you need to spend a few years in a spaceship in orbit around Saturn dreaming up millions of UML diagrams that when done, will magically barf out all of the code that makes up some enormous over-engineered enterprise fizzbuzz system. It takes a long time to overcome that nonsense without throwing away the goodness that exists here -- there's some excellent diagramming techniques that really help with coming up with a common understanding of how a system should work for a team and product owners and used well can bridge huge communication gaps. Many of the diagrams more or less show the same information, but with a slightly different angle that can help communication. The diagram grammars themselves can get really fussy and particular, but I think when they're used best only certain components of the grammars are used to fill very specific communication needs, the rest is more or less sketched in, and the remaining grammar can be pretty comfortably be left out. Many times, you can just invent a diagramming grammar that you can the other parties agree to and just "be inspired" by ideas from UML and get most of what you need done. There's also grammars that are not part of UML that would make sense for people to get familiar with. ArchiMate comes to mind as a particularly great example. I don't use it explicitly (the software tooling support for it is garbage, but you can fake it with yED pretty well), but I've used systems inspired by it numerous times to succinctly capture incredibly complex enterprise systems and data flow and tie those things to business processes and needs. https://en.wikipedia.org/wiki/ArchiMate https://en.wikipedia.org/wiki/ArchiMate

diminoten 8y ago
> Creating a bunch of UML diagrams up front is usually the sign of a broken software development process. Wait, what? Why? Assuming I'm doing them because they help me flesh out an idea, it should be fine, right? You're talking more about being forced to express a concept in UML when it's already adequately described in a non-UML format, right?

dry_flamingo 8y ago

http://www.nomnoml.com/ http://www.nomnoml.com/ is another good one. https://github.com/skanaar/nomnoml https://github.com/skanaar/nomnoml

seattle_spring 8y ago

> All You Need to Know About UML Diagrams Honestly thought it was just going to be a blank page.

GorgeRonde 8y ago

Some thoughts I've had on "graphical based programming" (if UML can be deemed as such): - Don't draw the product. Draw the organization that produces it. As per Conway's law, you'll be drawing the same thing in the end, but contrary to UML you won't face the problem of the representation of the product evolving faster than the ability of the organization to update it. The representation (the diagram) will just evolve as fast as the organization can represent itself. This require that: - The diagram is the organization and the fundamental aspect of code is UI. There is no distinction between the primitives of the UI/UX system (clicking on that, moving this item from here to there, etc ...) and its computational primitives. This is the tipping-point that: - a) makes this system homoiconic - b) makes this system homoschematic. Homoschematicity (same-representation/same-gesture in ancient Greek) is reached when the datastructure that is set in immediate relation to itself (typically lists in Lisp) is also what is directly presented to the end user and can be displayed as such, ie. immediately (lisp code is too ugly and limited for that).