Following on from my previous post (Software architecture as code) where I demonstrated how to create a software architecture model as code, I decided to throw together a quick implementation of a Spring component finder that could be used to (mostly) automatically create a model of a Spring MVC web application. Spring has a bunch of annotations (e.g. @Controller, @Component, @Service and @Repository) and these are often/can be used to signify the major building blocks of a web application. To illustrate this, I took the Spring PetClinic application and produced some diagrams for it. First is a context diagram.
Next up are the containers, which in this case are just a web server (e.g. Apache Tomcat) and a database (HSQLDB by default).
And finally we have a diagram showing the components that make up the web application. These, and their dependencies, were found by scanning the compiled version of the application (I cloned the project from GitHub and ran the Maven build).
Here is the code that I used to generate the model behind the diagrams.
The resulting JSON representing the model was then copy-pasted across into my simple (and very much in progress) diagramming tool. Admittedly the diagrams are lacking on some details (i.e. component responsibilities and arrow annotations, although those can be fixed), but this approach proves you can expend very little effort to get something that is relatively useful. As I've said before, it's all about getting the abstractions right.