#Sequence diagram if without else software#
#Sequence diagram if without else professional#
#Sequence diagram if without else series#

In general, objects are shown as rectangles.

Human objects are often indicated by a stick figure.

To help understand this, we’ll take this apart, one element at a time, looking at what each one shows us.Ī sequence diagram is composed of a number of columns, each headed by an object. Here is a sequence diagram for our “Score Essay” use-case.

Sequence diagrams allow us to demonstrate that our model suffices to represent a use case by mapping the steps of the use-case into specific messages (function calls) from one object to another.Īlthough sequence diagrams can be used to illustrate any interesting collaborations (sequences of related messages) among our objects, we most often draw one sequence diagram for each use case.

Our domain or analysis models view the world as objects that interact by exchanging messages. What operations are involved, and on which objects These diagrams attempt to show, for some specific use-case or some common interaction:

#Sequence diagram if without else software#

If you'd like to learn more and see a few features I didn't cover, I recommend you check out Mermaid.js' sequence diagram documentation.Īnd finally, I'm not done exploring what modern software engineers can do with Mermaid.js so stay tuned for more content! Mermaid.The syntax for the text describing the object is similar to the attributes in the class diagrams. Ultimately, I think Mermaid.js Sequence Diagrams are a good strategic tool for diagramming complex interactions or communicating complex concepts in a visual way in your documentation. Personally, I find Mermaid.js diagrams so convenient to use that I now find myself making sequence diagrams where I normally wouldn't have before due to the time and frustration required to build one. While sequence diagrams aren't necessarily beginner friendly, working with Mermaid.js sequence diagrams is exponentially less painful than trying to control a diagramming tool to generate and maintain these diagrams. Ultimately, I don't think I like this shorthand and instead prefer to use the activate / deactivate syntax for more readable sequence diagrams, but the option is there for you if you want it. Let's start with a simple sequence diagram representing a message from the client to the server and the server's response back.Įnter fullscreen mode Exit fullscreen mode If you're curious about this, however, I do have an article and video on understanding JWT authentication. However, the focus of the article's text will be on the diagrams themselves, not the process of JWT authentication. Over the course of this article, we'll create and expand a sequence diagram to explain JSON Web Token (JWT) authentication. If you're curious about sequence diagrams in general, a good starting point might be Visual Paradigm's Guide to Sequence Diagrams. This can help explain complex logic and interactions with a technical diagram and identify areas of confusion or misunderstanding.

Sequence diagrams represent systems and individuals as vertical columns and messages between these parts as horizontal lines that move across the various lanes to show how data flows between different pieces of the system.

#Sequence diagram if without else series#

Mermaid.js is available in a variety of tools, but I most frequently use it in GitHub markdown files and in Polyglot Notebooks.įor those of you who haven't been exposed, sequence diagrams describe a series of messages in a sequence between different objects. It also means that the diagram source is easily version-controlled and anyone on your team can modify it without special tooling or licenses.

This means your time is focused on actually writing the interaction logic instead of generating a visual.

#Sequence diagram if without else professional#

With Mermaid.js you can write a few lines of text and use its JavaScript library to generate a professional sequence diagram like the one below: Mermaid.js is the solution I needed 20 years ago. I distinctly remember working on sequence diagrams in my undergraduate computer science education and having so many issues trying to get the various boxes and arrows to look standard, rearrange shapes as I needed to expand the diagram, and generally focusing on anything but the logic the diagrams intended to create. Previously I've shown how Mermaid.js allows you to create entity relationship diagrams and class diagrams, but in this article we'll cover a far more complex diagram: the sequence diagram. I've been really enjoying seeing how Mermaid.js lets you generate technical diagrams from simple markdown.