Cartographer

Java codebase visualization tool. Generates a graph showing dependencies between modules. Groups mutually dependent modules into groups and removes edges that don't carry any new information for readability (transitive reduction).

By A depending on B I mean that either A uses B in its definition directly or that there is some other module that A depends on and that uses B.

Examples

Graph of this project:

Gson:

Other graphs can be found in example_graphs folder.

Usage

First we need graphviz or some way to use its fdp layout engine. Once we have it installed we can run:

mvn package
java -jar target/cartographer-[current-version].jar filters.txt [path to jar you want to graph] | fdp -Tsvg > output_file.svg

If you want to use this program with other layout engine, you will likely need to modify it a bit. Out of default layouts only fdp allows for defining connection from and to clusters.

Conclusions and future of this project

As you can probably see the results are kinda bad. Could try to make some small improvements by expermineting with grouping stuff into more clusters or by filtering out anything that gets defined by dependencies, but that won't really solve the core issue here.

The layout egnines in graphviz are simply not enough. Ideally we'd use something like force-directed graph for clusters of mutually recursive modules and hierarchical layout for the bigger structure (which does form a DAG), but I don't think graphviz supports that (and the dot layout seems to be kinda bad anyway for anything bigger). I could try laying out the graph myself and directly generating an .svg, but this was meant to be a small project and that'd require a lot more work on my part than I anticipated or am willing to spend time on right now.

Ultimately I'll leave this project as is. Might make some small tweaks to it if I feel like it, but I don't expect it to ever actually become significant help in familiarizing yourself with a codebase.