Add possibility to represent modules as C4 Components

[OLibutzki]

archifacts models modules of a monolith as containers. Due to this converation with @simonbrowndotje they should be modelled as components.

Unfortunately, the Structurizr Java API is limited and does not provide all the features we need to model modules as components appropriately.

As an alternative we could think about generating PlantUML directly using the C4-PlantUML-Stdlib or generating Structurizr DSL Code.

At first glance the DSL approach seems to be the better choice as it abstracts from the concrete technology (PlantUML).

It seems to be possible to parse the generated DSL files using StructurizrDslParser.

As part of this issue it should be possible to decide how modules should be represented in the C4 model.
archifacts should support representing them as containers (distributed system) or components (modular monolith).

[simonbrowndotje]

Unfortunately, the Structurizr Java API is limited and does not provide all the features we need to model modules as components appropriately.

At first glance the DSL approach seems to be the better choice as it abstracts from the concrete technology (PlantUML).

The DSL parser uses the Java API, so anything you can do with the DSL is possible with the Java API. As an example, the parser for the component DSL keyword just calls container.addComponent() -> https://github.com/structurizr/dsl/blob/master/src/main/java/com/structurizr/dsl/ComponentParser.java

[OLibutzki]

Thanks for clarifying, @simonbrowndotje.

Well, after investigating the PlantUML-Stdlib I realized that code elements are not part of the lib, too. So it feels like both of my ideas don't work.

So there is no specific visual C4 representation for code elements and the relationships between them, right? A classic UML class diagram for the rescue?

[simonbrowndotje]

So there is no specific visual C4 representation for code elements and the relationships between them, right? A classic UML class diagram for the rescue?

There is no "specific visual C4 representation" for any of the C4 model diagrams (the C4 model is notation independent), so yes, a UML class diagram is a good approach for level 4 -> https://c4model.com/#CodeDiagram