java_visualize: visualization for java
David Pritchard (daveagp@gmail.com), created May 2013
This is the frontend for a Java visualizer. It is based on "Online Python Tutor",
a Python visualizer by Philip Guo. Try it at these mirrors (as of time of writing):
http://cscircles.cemc.uwaterloo.ca/java_visualize/ (Java 8)
http://www.cs.princeton.edu/~cos126/java_visualize/ (Java 7)
The Online Python Tutor repo contains both a frontend and backend.
For Java wre readapt the frontend (so this repo contains OnlinePythonTutor
as a subrepo) and replace the backend (it is in the java_jail repo mentioned
below, since it runs in a sandbox).
INSTALLATION
Install these on your server first:
https://github.com/cemc/safeexec
https://github.com/daveagp/java_jail
This requires root access. See the instructions therein for details. It is best to
install these in locations that are not served to users by your web server.
Next, in some folder accessible to your web server, run
git clone --recursive https://github.com/daveagp/java_visualize
It's recursive because it includes two submodules. Because of this,
to update, use the pair of commands
git pull; git submodule update
At this point, visiting
http://your.website/url/to/java_visualize/
should give you a beautiful (but non-working) frontend, and
http://your.website/url/to/java_visualize/java_safe_ram_maketrace.php
should give you a "Couldn't find jv-config.json" error.
Next, copy jv-config.example.json to jv-config.json. Now visiting
http://your.website/url/to/java_visualize/java_safe_ram_maketrace.php
should give you a "http mangling" error.
Finally, edit jv-config.json to indicate where you installed safeexec
and java_jail. (Just those first two entries need to be changed right now.)
Now, try the visualizer out!
THE "C++ VISUALIZER"
See cpp_visualizer.txt.
FAQ
-- click on "Click for FAQ" on the visualizer page
MORE INFO
-- index.html is a modified version of visualize.html
-- jv-frontend.js is a modified version of opt-frontend.js
-- java_safe_ram_maketrace.php connects the frontend to the backend
-- config.* is used for configuration stuff specific to your server
-- pytutor-customizations.{js,css} overrides some behaviour of OPT
-- example-code is a directory full of example Java files to visualize
Note that in the entire frontend, only the two .php files are
written in a server-side language. Everything else we use is static,
although OnlinePythonTutor has some server-side files that this Java
version does not use.
If you use a database, you'll be putting a DB password in jv-config.json.
Please check that
http://your.website/url/to/java_visualize/jv-config.json
is inaccessible; .htaccess tries to do this, but you should confirm it works.
====
The modified files (index.html, jv-frontend.js) retain the MIT license
under which they were published in the OnlinePythonTutor repo.
The other files are released under
the GNU Affero General Public License, versions 3 or later. See LICENSE
or visit: http://www.gnu.org/licenses/agpl.html