Homepage: https://github.com/skeeto/emacs-java
Updated:
Java and java-mode Emacs enhancements
This package provides a minor-mode that enhances java-mode a bit
when working with Ant-based projects. This is something to do
*instead* of using a large extension like JDEE, which is large,
complex, difficult to set up, and doesn't work very well anyway.
I'm not a fan of giant IDEs. In a corporate setting, someone who
doesn't know what they're doing will usually pick a big IDE for you
and make it difficult to use anything else. I think everyone should
be able to use their preferred source editing tools, whether it be
Emacs, Vim, or Eclipse.
The unix-way is to make many small, well-defined and well-focused
programs do all the work, so that's what I recommend below. Ant for
project management, Ivy for dependency management, AStyle for
syntactic style, Checkstyle for semantic style, and (not so small)
Emacs as the magic wand that directs all the tools. It's like The
Sorcerer's Apprentice, but with positive results.
With all these tools, the downside compared to a big Java IDE is no
tool has a complete understanding of the code base. Java is a
verbose language and it helps when the computer can fill in all the
redundant details for you. I don't think Emacs will ever be able to
do this as completely as an IDE. However, I think Emacs provides
plenty of advantages to counter that level of code awareness.
It is strongly recommended to use in conjunction with this package:
* java-docs - Found alongside java-mode-plus. Provides the
`add-java-import' function for quickly adding import
statements to the top of the source file.
* ido-mode - Packaged with Emacs for great minibuffer completion.
* winner-mode - Maximize Emacs, split into a bunch of windows, and
hop around them quickly with this.
Enhancements to java-mode:
* `ant-compile' - Like normal `compile', but automatically search
up the path looking for a build.xml.
* `open-java-project' - Use this on your project's root
directory. Open up an entire source hierarchy at once, making
it easy to switch between source files with ido-mode, and at
the same time exposing lots of names for `dabbrev-expand'
(M-/) to use.
* `ant-bind' and `ant-bind*' - Create a keybinding for a specific
Ant target. These have already been defined.
* C-c C-j c - "compile" target
* C-c C-j j - "jar" target
* C-c C-j C - "clean" target
* C-c C-j r - "run" target
* C-c C-j t - "test" target
* C-c C-j y - "check" target, if you're using Checkstyle
* C-c C-j f - "format" target, if you set up a Java indenter
* C-c C-j x - "hotswap" target, if you set up Ant hotswap
Also provided is `java-mode-short-keybindings', which sets up
shorter bindings by replacing C-c C-j with C-x. This is not the
default because they trample the keybinding namespace a bit,
but they are the bindings I personally use.
These compilation bindings all accept a prefix argument, which
appends the number to the compilation buffer name. This is
useful when you need to run two compilation buffers at once:
give each one a different prefix. My favorite use of this is
for code hotswapping.
* `insert-java-import' - If you have java-docs set up, you can
access the quick import insertion function.
* C-c C-j i - quickly select an import to insert
Recommended usage:
A typical Ant-based project typically consists of a directory
layout like so,
src/ - source files
test/ - JUnit test source
doc/ - documentation, not including generated (Javadoc)
dist/ - final deliverable, created and destroyed by Ant
build/ - generated/compiled files, created and destroyed by Ant
See my SampleJavaProject for an example of this in action,
https://github.com/skeeto/SampleJavaProject
Like using the mouse, I like to avoid dropping to a shell whenever
I can, even if that shell is inside Emacs. If I can stay inside the
context of Emacs, that's really what I prefer to do. Emacs provides
a generic front end to various source management systems (`vc-*'),
but my favorite one is Git. I use Magit to interface with Git, and
I rarely have to visit the shell to perform maintenance. Figure out
what works best for you.
Use Emacs in daemon mode! This got *really* good in recent versions
of Emacs, so use it! You can either fire off an 'emacs --daemon'
when you first log in, and then use 'emacsclient' later, or you can
use "emacsclient -ca ""' any time you need to use Emacs, which will
create a daemon for you if needed. As you'll see below, once you're
set up with your project, you don't want to make Emacs do it all
over again when you get back from lunch.
You'll want to dedicate a(n Emacs) window specifically to the
*compilation* buffer. Any time you do a compilation, it will
reliably be done here, rather than hopping around to various
windows. I make mine a half-tall window on the top right.
So when you sit down to do some work at a fresh Emacs instance, the
first thing you will do is run `open-java-project' on your
project's root directory (this may not be practical on very large
projects). This will open all of your sources so they're very
accessible. Using ido-mode will make switching between the sources
pretty zippy.
To help navigate, take advantage of a TAGS file. Use `find-tag'
(M-.) to move around your source. You can set up an Ant "tags"
target like so,
Hack away at the code, using `dabbrev-expand' and family to help
save time typing. When it comes time to compile, use the C-c C-j c
binding. Need to run your program? Use the C-c C-j r binding, and
it will launch from Emacs. Use C-x ` to step through and correct
the errors.
With tabs turned off (`indent-tabs-mode'), Emacs should do a good
job of indentation, but a tool like Artistic Style (AStyle) can
tidy up a bit better. Use C-c C-j f to syntactically tidy up your
changes (and you'll need to `revert-buffer' to get the style fixes
in the buffer, so I recommend binding it to something). I recommend
setting up a "format" target to do this like so,
Adjust to taste.
AStyle checked your syntax style, so next Checkstyle can check your
semantic style. So if you're using Checkstyle, which I also
recommend, you'll use C-c C-j y to check and correct (with C-x `)
any issues.
Once you're satisfied, use your preferred Emacs SCM interface to
check in your code. Repeat.
If you want to run a particular target not bound to a short key
binding, use `ant-compile', which will ask you for the Ant command
you want to use. You can run this from any source file, and it will
go find your build.xml. No need to add a "-find".
Closing remarks:
As I develop and improve my Java workflow, I'm gradually building
up java-mode-plus to match. As long as I continue to use Java, this
package will slowly grow.