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Drawing simple diagrams with yUml

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08 / Sep  2015

Lately I was starting yet another project for learning/fun purposes. Since recently I’m a big fan of Scala and Akka there’s no secret I decided to start distractor using them. The project is based upon reactor and it’s aim is to allow distribution of transports and reactors across multiple nodes/JVMs.

So, there I was, with a started project, with already some code committed. What I wanted to do next was to somehow document the architecture of the underlying actor model. I didn’t want to use any sort of visual diagram generators, since I don’t like the drawback of being forced to maintain multiple file versions of created diagram or to export the jpg/png/svg file to include it into wiki.

So while searching the depths of internet I’ve come across yUml. It turned out to be great for my needs. It allows creation of simple diagrams from plain text! For me it’s great, since I can simply write such diagram and put it into code repository. That’s it.


So let’s quickly evaluate the possibilities which are given by this tool. So far with yUml everyone is able to create three types of diagrams: class, activity, use case. So far I only needed to create something which could demonstrate my actor architecture. So obviously the class diagram suited me the most.

So lets examine some easy class diagram:

[Order]-[note:Aggregate root{bg:wheat}]

What we can expect from the output image? So there should be:

So lets take a brief look at the result:

Diagram .

Yay!. That’s what it is all about. It’s also easy to include into markdown:

![Diagram]([Customer|-forname:string;surname:string|doShiz()]<>-orders*>[Order],[Order]++-0..*>[LineItem],[Order]-[note:Aggregate root{bg:wheat}])

More examples can be found here:

Outcome for my project

After playing a little bit with yUml, I’ve achieved a diagram which was currently matching the actor system architecture. Of course it’s not a class diagram per se, since Actor modelling in Akka is different than writing imperative code. However class diagram served me good for the goal I was trying to achieve. From the diagram, it’s easy to see how the actors are structured in my application.

Actor System Overview


Of course as to all tools, there are some compromises. What I’ve found most disturbing was the fact, that referencing entities with additionals (colors, fields or others) doesn’t work if the entity isn’t placed with them every time it is referenced. So I can imagine that creating more complex diagrams could be a pain.

So hence, one conclusion for yUml is that it could be a perfect tool for creating small and quick documentation for our code. If someone would like to create a heavy code documentation out of it - no.. don’t do it.

One thing to mention here is that the tool is free of charge so far. However I have seen pro-account link on the yUml page. Didn’t click though.