Written by Martin Lehmann, Kristine Schaal and Rüdiger Grammes

Version 0.2

see https://github.com/accso/java9-jigsaw-depvis

DepVis visualizes dependencies of Java 9 Jigsaw modules as defined in Project Jigsaw by [JSR 376] (https://www.jcp.org/en/jsr/detail?id=376) and JEP 261. DepVis produces a GraphViz output file (DOT file) which can be rendered with GraphViz in a separate step.

Result looks like this (in this case all Java 9 system modules (build b162) are visualized with all relationships, limited to modules with prefix "java.*"):

1. Requires/Read relationships (currently visualized as a blue arrow)
   • requires mandated to java.base (dashed blue arrow)
   • requires transitive (blue arrow)
2. Exports-To relationships (red)
3. Requires transitive transitivity (green arrow)
   • If moda--requires-transitive-->modb (blue) and modc--requires-->moda (blue), then also modc--requires-->modb (green). Note that this is currently limited to 1-transitivity.

1. DepVis can be configured, see section below.
2. A legend is written in the top left corner. As this unfortunately flips the whole graph, this is done as a separate graph.
3. A helper printer tool is also included which prints the relationship to STDOUT.

![Legend] (legend.jpg)

1. Clone this repo.
2. Install a Java 9 JDK with Jigsaw support. DepVis has been tested with b162 as of March 2017.
3. Install GraphViz 2.38.
4. If running on Windows, install a bash, like for example Babun
5. Edit file env.sh to configure JAVA_HOME and GRAPHVIZ_HOME (see TODO markers)
6. Call clean.sh, compile.sh and run-vis.sh (or all.sh for all in one step).
7. Output is moduledependencies.dot and moduledependencies.png (and a second file pair ...with-legend).

DepVis can be configured in a configuration properties file (see depvis.properties) as follows:

1. depvis.includeFilter
   • comma-separated Strings
   • module names whitelist, all used to be checked with String.startsWith
   • if not set, all modules from system and/or module-path will be used
   • example: java.,jdk.
2. depvis.excludeFilter
   • comma-separated Strings
   • module names blacklist, all used to be checked with String.startsWith
   • if not set, all modules from system and/or module-path will be used
   • example: jdk.internal
3. depvis.useSystemModules
   • boolean
   • do we want to visualize modules from system (i.e. java.*, jdk.* etc.)?
4. depvis.useModulePath
   • boolean value
   • want to visualize modules from a module path
   • if so, depvis.modulePath needs to be set
5. depvis.modulePath
   • path Strings, separated by system's file separator)
   • set a local module path
   • example: /jigsaw/example/mlib
6. depvis.showRequires
   • boolean
   • want to visualize requires/reads relationships?
7. depvis.showRequiresMandated
   • boolean
   • want to visualize requires/reads mandated relationships?
8. depvis.showRequiresTransitive
   • boolean
   • want to visualize requires/reads transitive relationships (1-transitive)?
9. depvis.showExportsTo
   • boolean
   • want to visualize exports-to relationships?
10. depvis.outputFileName
    • String
    • filename for the DOT output file
    • example: /tmp/moduledependencies.dot
11. depvis.showLegend
    • boolean
    • want to visualize a legend plus title and timestamp?
    • if so, the graph will be flipped to LR
12. depvis.diagramTitle
    • String
    • configure a title for the diagram

No software is ready, ever ;-) So here are some ideas left (any other feedback very welcome!):

• Show requires transitive dependencies with a different line style
• Include n-transitivity for requires-transitive
• Allow filtering of individual relationships (black/white listing)
• Include uses/provides relationships
• Include the module's package names
• Include a module's hash value
• Currently, DepVis only shows modules from the Observable Modules (= module path and system modules). Alternatively allow to show modules from a Configuration.
• Allow to configure colors, edge styles, node styles/shapes etc. via config file from outside (currently one needs to change Java class depvis.GraphVizHelper.java and recompile).
• Adding a GraphViz legend seems only possible with rankdir=LR. This settings then flips the whole graph (as it cannot be done in a subgraph only). Any way to get around this?
• Write the package name(s) to an exports-to edge
• Layouting: Any text added as label to an edge should be visualized "closely"
• Open Modules as new module type
• usage of "opens" in module-info

• "requires public" in the module-info is now "requires transitive".

Jigsaw examples, see https://github.com/accso/java9-jigsaw-examples : Java 9 Jigsaw modules example suite

Thx to the GraphViz team (http://www.graphviz.org) for this magic tool!

Thx also to Kohsuke Kawaguchi for his graphviz-api at https://github.com/kohsuke/graphviz-api! We have forked his API to https://github.com/MartinLehmann1971/graphviz-api and made a few minor changes (mainly to avoid duplicates of GraphViz Nodes based on their ID).