NOTE: ajoke as a separate project may not work anymore. It’s part of my system-config project, you may want to check that project instead.
I tried to make it a self-contained project, but seems it’s too much hassle. Especially after I started replacing GNU Global with beagrep (beatags, to be more precise).

What is ajoke

Abducting Java Onto Emacs, K is silent.
A Joke Of Kidding Eclipse.

Ajoke is a tool for doing Java programming on Emacs. It is inspired by Emacs-Eclim, but does not depend on Eclipse. Instead, it uses beagrep and ctags-exuberant extensively, with a bunch of Perl scripts.

For a demo, you can watch the video I made at Youtube (also on youku for my countrymen behind Great Free Wall, but the quality is bad because youku sucks).

Why ajoke

Well, I tried Emacs-Eclim, it was nice. But it has dependency on Eclipse, which is awful: it is very slow with large projects. I tried to put the whole android source tree into Eclipse, it was still doing background indexing the next day. Strace showed that it is scanning all those binary files under .git and .repo/projects. I finally killed it.

But I really liked a couple of things Emacs-Eclim did, for e.g., draw the class/interface inheritance hierarchy; automatically import missing classes. So I took the ideas and extended it with source code reading in mind: with Emacs-Eclim, when a hierarchy contains android.view.View, you can’t easily jump over to that class to take a peek, because that class is from a .jar file in the Android SDK; but with ajoke, android.view.View can be also from GNU Global GTAGS database, which is in turn built from the Android source code (of course, because GNU Global is a source code tagging tool great for code reading), so you can easily jump over to that class and have a sense of The Big Picture:-)

Plus, by hacking this tool, I hope it will also support other programming languages better, such as C#, which is very like Java in my opinion. This is unlike JDEE, which will remain Java only I think. For e.g., I have hacked GNU Global a bit, so that it will be very quick to query android.view.View as a whole. But that will be another blog post (which I will add the link Inside Ajoke here after I write it).

How to tell ajoke

Check out the source code

git clone --recursive -b gnu-global https://github.com/baohaojun/ajoke

Note the –recursive option, it’s important because I have 2 submodules in ajoke, my patched versions of GNU Global and ctags-exuberant.

Also note the -b gnu-global option, it’s because the master branch of ajoke has switched to use beagrep instead of GNU Global for Java indexing, and is currently broken except for my own system-config.

Set up the env

If you are using Debian or Ubuntu, I have provided a test drive script named ajoke-test-drive, so after you check out ajoke, you can simply type ./ajoke/bin/ajoke-test-drive to have a taste of it.

If you are not using Debian alike systems, then please follow these steps, supposing ajoke is checked out in $AJOKE_DIR (in my case, it is ~/system-config/gcode/ajoke, yours may vary):

Put ajoke scripts into you PATH and Perl PATH:

export AJOKE_DIR=~/system-config/gcode/ajoke #PLEASE MODIFY THIS TO SUIT YOUR CASE
export export PATH=$AJOKE_DIR/bin:$PATH
export PERL5LIB="$AJOKE_DIR/etc/perl:$PERL5LIB";

It may be a good idea that you put these into your .bashrc, and restart your Emacs with these environment variables set.

Install 3 cpan modules

String::Approx, String::ShellQuote, Text::Glob (as debian packages, they are named libstring-approx-perl, libstring-shellquote-perl and libtext-glob-perl)

Compile and install the patched version of Gnu Global

This code is available at external/global, it will be checked out together with ajoke if you used the –recursive option when cloning ajoke.

cd ./external/global
sh ./reconf.sh
./configure
make -j8
sudo make install

If the compilation fails because of missing dependencies

If you are on Debian family, you can try to install the dependencies with the following commands. I tried them myself on a clean minimal Debian system built using pbuilder, and GNU Global compiles just fine after the dependencies resolved.

apt-get build-dep global

apt-get install sudo bash-completion autoconf automake \
    bison exuberant-ctags flex \
    gperf libltdl-dev libtool netbase \
    openjdk-6-jdk strace tasksel git python python3 \
    libstring-approx-perl libstring-shellquote-perl \
    libtext-glob-perl liburi-encode-perl

Compile and install ctags-exuberant

Ctags-exuberant is also provided as a git submodule, under external/ctags-exuberant.

cd ./external/ctags-exuberant
autoreconf -i
./configure
make -j8
sudo make install
sudo mv /usr/local/bin/ctags /usr/local/bin/ctags-exuberant

Copy the .globalrc and .ctags into your HOME

Suppose your global installed into /usr/local/bin/global, then global_prefix=/usr/local

global_prefix=/usr/local
perl -npe "s,\@prefix\@,$global_prefix,g" $AJOKE_DIR/external/global/gtags.conf.in > ~/.globalrc
ln -sf $AJOKE_DIR/etc/.ctags ~/

Create Gnu Global tags for JDK

Taking my openjdk installation as e.g.:

cd /usr/lib/jvm/java-6-openjdk-amd64
mkgtags

Alternatively, you can use Android source tree as the fallback tags (my android is at ~/src/android):

cd ~/src/android
mkgtags

Create gtags for your Java project

And add the JDK or Android as fallback:

cd ~/your-java-project
mkgtags
java-add-fallback /usr/lib/jvm/java-6-openjdk-amd64
# or java-add-fallback ~/src/android, but not both
# as it'd be a waste of time to find 2 copies of java.lang.String

Require $AJOKE_DIR/etc/elisp/ajoke.el in your `~/.emacs`

Start Emacs with the environment variables set correctly, and start laughing with Ajoke:-)

You can refer to the test driver script if there are any problems. In the mean time, I will try to make ajoke-test-drive support more systems.

Ajoke with its friends

Another tool very useful for code reading is beagrep, grep 2G source code in 0.23 second. For e.g., compared to JDEE, ajoke can’t do caller/callee look up, but its friends beagrep and ctags-exuberant can do it.

Most of other ajoke’s friends are still unborn in my personal system-config project.

Acknowledgments

Thank Emacs-Eclim and JDEE for the inspiration. Thank GNU Global for using B+ tree to query tags (it’s so fast!), and ctags-exuberant for supporting so many programming languages.

baohaojun/ajoke