#+TITLE: JavaInspect - Utility to visualize java software

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* General
- This program is free software: you can redistribute it and/or modify
  it under the terms of the [[https://www.gnu.org/licenses/lgpl.html][GNU Lesser General Public License]] as
  published by the Free Software Foundation, either version 3 of the
  License, or (at your option) any later version.

- Program authors:
  - Svjatoslav Agejenko
    - Homepage: http://svjatoslav.eu
    - Email: mailto://svjatoslav@svjatoslav.eu
    - [[http://www.svjatoslav.eu/projects/][Other software projects hosted at svjatoslav.eu]]

  - Tony Bargnesi
    - GitHub fork for the project:
      https://github.com/abargnesi/javainspect

** Source code
- [[http://www2.svjatoslav.eu/gitweb/?p=javainspect.git;a=snapshot;h=HEAD;sf=tgz][Download latest snapshot in TAR GZ format]]

- [[http://www2.svjatoslav.eu/gitweb/?p=javainspect.git;a=summary][Browse Git repository online]]

- Clone Git repository using command:
  : git clone http://www2.svjatoslav.eu/git/javainspect.git

* Goal and operating principle
Goal: simplify/speed up understanding the computer program code by
automatically visualizing its structure.

[[http://www3.svjatoslav.eu/projects/sixth-3d/graphs/][See example produced graphs]] for [[http://www3.svjatoslav.eu/projects/sixth-3d/][Sixth 3D - 3D engine project]].

JavaInspect can be used as a [[id:acf1896a-74b4-4914-acf6-a77075e07f25][standalone commandline utility]] as well as
[[id:bbeeffc8-3767-440d-8d93-ec9124dd60ee][java library]]. JavaInspect uses primarily Java built-in reflection to
discover and visualize any part of Java program.

JavaInspect currently has no GUI, configuration files, embedded
scripting support, direct Maven or Ant integration. See [[id:2ad2889e-6c95-4662-b3f4-2c341fc74522][usage]] to learn
how to instuct Javainspect what to do.

After discovering application structure and optionally filtering out
unimportant parts, JavaInspect produces GraphViz dot file that
describes data to be visualized. Then launches GraphViz to generate
bitmap graph in PNG or SVG format.

By default on your Desktop directory when operated in library mode or
current working directory when operated as standalone commandline
application.

Notes:
+ JavaInspect is developed and tested so far only on GNU/Linux.
+ See: [[https://github.com/pahen/madge][Madge - similar tool for JavaScript]]

* Example graphs
+ A very simple example:

    [[file:example.png][file:example.resized.png]]

    Graph legend:

    file:legend.png

+ [[http://www3.svjatoslav.eu/projects/sixth-3d/graphs/][See example produced graphs]] for [[http://www3.svjatoslav.eu/projects/sixth-3d/][Sixth 3D - 3D engine project]].

* Usage
  :PROPERTIES:
  :ID:       2ad2889e-6c95-4662-b3f4-2c341fc74522
  :END:
JavaInspect can be controlled in 2 different ways:
+ [[id:acf1896a-74b4-4914-acf6-a77075e07f25][as standalone commandline utility]]
+ [[id:bbeeffc8-3767-440d-8d93-ec9124dd60ee][as embedded Java library via Java API]]

** usage as commandline utility
   :PROPERTIES:
   :ID:       acf1896a-74b4-4914-acf6-a77075e07f25
   :END:
To enable commandline support, (study and) execute script:
: commandline launcher/install

Warning: It was tested only on Debian Stretch linux.

Available commandline arguments:
#+BEGIN_VERSE
-j (existing files)...
    JAR file(s) to render.

-n (mandatory, string)
    Graph name.

--debug
    Show debug info.

-k
    Keep dot file.

-h
    Hide orphaned classes.

-w (one to many strings)...
    Whitelist glob(s).

-b (one to many strings)...
    Blacklist glob(s).

-d (existingdirectory)
    Target directory. Default is current directory.

-t (options: png, svg)
    Target image type. Default is: svg.
#+END_VERSE
** usage via Java API
   :PROPERTIES:
   :ID:       bbeeffc8-3767-440d-8d93-ec9124dd60ee
   :END:
Requires that classes to be visualised are available in the classpath.

To get JavaInspect into same classpath with your projecs I so far came
up with 2 solutions:

1. Add JavaInspect library in your project as a dependency.

2. Create new Java project for the purpose visualizing your other
   projects and include JavaInspect and your projecs binary artifacts
   (Jar's) into new project classpath. Built binary Jar's (with no
   source code) are sufficient because JavaInspect operates via
   reflection.

Simple Java based control/configuration code needs to be written for
each project. I usually put such code into directories devoted for
JUnit tests. Because it needs not to be compiled/embedded into final
product or project artifact I'm just willing to visualize.

Control code in general does the following:
1. Create graph object.
2. Java reflection/classloaders does not provide mechanism for
   discovering all classes under given package. Therefore you need to
   declare at least some classes to be added to the graph by:
   + Manually adding individual classes to the graph.
   + and/or: Let GraphViz recursively scan and parse specified
     directories with Java source code files to discover class names.
   + For every class added to the graph, GraphViz will recursively
     inspect it and add all referecned classes to the graph as well.
3. Graphs easilly get very big and complex so optionally we filter
   important code using classname wildcards patterns based blacklist
   and/or whitelist.
4. Optionally we can tune some rendering parameters like:
   + Possibility to remove orphaned classes (classes with no
     references) from the graph.
   + Specify target directory for generated visualization
     files. (Default is user desktop directory)
   + Keep intermediate GraphViz dot file for later inspection.
5. Render graph.


*** example 1: individually picked objects
This example demonstrates generating of class graph from hand picked
classes and visualizing GraphViz itself.

#+BEGIN_SRC java

// Create graph
final ClassGraph graph = new ClassGraph();

// Add some random object to the graph. GraphViz will detect Class from
// the object.
graph.add(graph);

// Also add some random class to the graph.
graph.add(Utils.class);

// Keep intermediary GraphViz DOT file for reference.
graph.setKeepDotFile(true);

// Produce bitmap image titled "JavaInspect.png" to the user Desktop
// directory
graph.generateGraph("JavaInspect");

#+END_SRC

Note: if desired, more compact version of the above:
#+BEGIN_SRC java
new ClassGraph().add(randomObject, RandomClass.class)
                .setKeepDotFile(true).generateGraph("JavaInspect");
#+END_SRC


Result:
    - Generated DOT file: [[file:JavaInspect.dot][JavaInspect.dot]]
    - Generated PNG image: [[file:JavaInspect.png][JavaInspect.png]]

*** example 2: scan java code, apply filters
#+BEGIN_SRC java
// Create graph
final ClassGraph graph = new ClassGraph();

// Recursively scan current directory for Java source code and attempt
// to detect class names from there to be added to the graph.
graph.addProject(".");

// Blacklist example classes from being shown on the graph
graph.blacklistClassPattern("eu.svjatoslav.inspector.java.structure.example.*");

// do not show single classes with no relationships on the graph
graph.hideOrphanedClasses();

// Produce bitmap image titled "JavaInspect full project.png" to the
// user Desktop directory.
graph.generateGraph("JavaInspect full project");
#+END_SRC
Result:
    - Generated PNG image: [[file:JavaInspect%20full%20project.png][JavaInspect full project.png]]

*** example 3: GraphViz embedded in another project
1. Download project Sixth [[http://www2.svjatoslav.eu/gitweb/?p=sixth.git;a=snapshot;h=HEAD;sf=tgz][code snapshot]].
2. Inspect and run *DataGraph.java*.

*** Embedding JavaInspect in your Maven project

Declare JavaInspect as dependency:
#+BEGIN_SRC xml
<dependencies>
    ...
    <dependency>
        <groupId>eu.svjatoslav</groupId>
        <artifactId>javainspect</artifactId>
        <version>1.6</version>
    </dependency>
    ...
</dependencies>
#+END_SRC


Add Maven repository to retrieve artifact from:
#+BEGIN_SRC xml
<repositories>
    ...
    <repository>
        <id>svjatoslav.eu</id>
        <name>Svjatoslav repository</name>
        <url>http://www2.svjatoslav.eu/maven/</url>
    </repository>
    ...
</repositories>
#+END_SRC

* Requirements
[[http://www.graphviz.org/][GraphViz]] - shall be installed on the computer.

On Ubuntu/Debian use:
#+BEGIN_SRC sh
sudo apt-get install graphviz
#+END_SRC
* TO DO
Note: Because this is side project (and I have many of them) I can
only contribute few hours per year at average. Any help is welcome.  A
LOT of cool ideas could be implemented. For intstance:

- BUG: Should not hide references if there are too many of them to
  classes if referring classes are not visible anyway because of
  blacklist/whitelist rules. Basically reference counting should
  exclude not visible classes.

- BUG: Orphaned class removal does not work always. There are many
  bugs and corner cases to find and fix still.

- BUG: Code is not very readable. Document and refactor for better
  maintainability.

- FEATURE: Create installable DEB package.
  - Submit it to some Debian developer for integration or become
    Debian package maintainer.

- FEATURE: Make it modular. That is: central part, an application
  model could be standalone and serializable.

  - There could be multiple ways to acquire model:
    - By introspecting application via Java reflections (current mode
      of operation).
    - By parsing java source. (unfinished)

  - There could be ways to manipulate model:
    - Store/load/compare.
    - Trim uninteresting parts.
    - Highlight important parts.

  - There could be multiple ways to render model:
    - PNG/SVG (currently implemented)
    - PlantUML (TODO)
    - Interactive 3D visualization (TODO)

- FEATURE: Replace internal java parser in package
  eu.svjatoslav.inspector.java.methods with: https://javaparser.org/

- FEATURE: Integarte with [[http://plantuml.com/class-diagram][PlantUML]].

- FEATURE: Add dark theme for generated graphs.

- FEATURE: Sort Class fields by alphabet.

- FEATURE: Visualize also concrete field values so it could be used as
  ultra cool runtime logging/debugging framework.

- FEATURE: Possibility to visualize structure and data from JVM
  snapshot.

- FEATURE: Possibility to attach to remote process to visualize
  data/structure using JVM debug port and mechanism.

- FEATURE: Possibility to attach to JVM using JVM agent.

- FEATURE: Possibility to inspect graphs in 3D using [[http://www2.svjatoslav.eu/gitbrowse/sixth-3d/doc/index.html][Sixth 3D engine]].

- FEATURE: Possibility to select classes/fields/values to be
  visualized in some graph query language. For greater flexibility in
  comparison to currently supported glob syntax.

- FEATURE: Add option to control JavaInspect via JSON or XML config
  file. For example different graphs for given project could be
  defined once in plain text config, possibly with the aid of some
  interactive utility. Then defined graphs could be updated as part of
  project build or release process.

- FEATURE: Configurable maven plugin to generate graphs as part of the
  project build/release process.