Setting Up CheckStyle

Setting Up Checkstyle

checkstyle_files

Go to our Main Repository and download these 2 files under the Miscellaneous folder.

checkstyle-8.2-all.jar - this provides the actual checkstyle program
cs2030_checks.xml - this provides the configuration file specifically for CS2030 for checkstyle

Make sure you save them to a directory that you can remember. In this case, I chose to save them to ~/checkstyle_files.

checkstyle_1

In the shell, change directory to the folder where you saved the files, with cd /place/where/you/saved/the/files.
Check that the files are there with ls.
Your download files should already have the right read permissions, but we will set it again just to be sure. Run chmod u+r checkstyle-8.2-all.jar cs2030_checks.xml. What this command does is that it CHanges the MODe of the files (i.e. its permissions), and adds read (+r) to the user (u+r).
To help us accurately determine the location of the files later, run realpath -e checkstyle-8.2-all.jar cs2030_checks.xml (yes I missed out the -e switch in the screenshot above). realpath outputs the full absolute file path while the -e switch ensures it checks for file existence first.

checkstyle_2

Now that we know the absolute location of the two files, we can create our very own checkstyle command. Run, in a single command, echo 'alias checkstyle="java -jar your/full/filepath/here/checkstyle-8.2-all.jar -c your/full/filepath/here/cs2030_checks.xml *.java"' >> ~/.bashrc.

remember to swap out the directories in the command above with your actual directories you found in step 5
make sure you have TWO right brackets >> instead of one. the two right brackets ensures it appends to the ~/.bashrc file instead of rewriting it.
if you use any other shell like zsh or fish, please change the command to work with your respective shell configuration files, e.g. ~/.zshrc

For me, I ran echo 'alias checkstyle="java -jar /home/chris/checkstyle_files/checkstyle-8.2-all.jar -c /home/chris/checkstyle_files/cs2030_checks.xml *.java"' >> ~/.bashrc.

What this command does is that it appends the line alias checkstyle="java -jar /home/chris/checkstyle_files/checkstyle-8.2-all.jar -c /home/chris/checkstyle_files/cs2030_checks.xml *.java" to the end of your shell configuration file (commonly ~/.bashrc). Your shell configuration file is ran (or more accurately, sourced) whenever you start your shell.

As for alias checkstyle="java -jar /home/chris/checkstyle_files/checkstyle-8.2-all.jar -c /home/chris/checkstyle_files/cs2030_checks.xml *.java", what this does is that it sets a command alias called checkstyle, so that whenever you run checkstyle in your shell, it will run java -jar /home/chris/checkstyle_files/checkstyle-8.2-all.jar -c /home/chris/checkstyle_files/cs2030_checks.xml *.java, which is the command to properly run checkstyle and load the configuration file in java.

Restart your shell, i.e. close it and start it again. (alternatively, you can just run source ~/.bashrc)
Change directory to a directory with .java files and run checkstyle. It should work now.

checkstyle_3