Posts tagged checkstyle

Firstly, in almost every development project that has not passed its prime, everyone adheres to some kind of coding checklist. But overtime (especially during the maintenance and support phase) the topic becomes like a lip service, in most scenarios no one would govern it, everyone cuts some slack and the source code becomes an expensive garbage.

Or worse of all, someone comes up with some coding checklist full of anti-patterns. :)

Checkstyle is a very mature code checking library developed some time ago for this purpose.

Today we are going to show you how to integrate checkstyle into your Maven build. I use Maven for project development management but you can do equally well with Ant or other build tools. (Just to note that Maven is not just a build tool! :P)

Assumptions 

1. You are using Maven

2. You have installed CheckStyle plugin in your Eclipse IDE (Fine if you are not using Eclipse, you may run parts of the example off from the command line $mvn)

3. You are using Eclipse IDE@@ (Again, you don’t have to although most of example here will illustrate using Eclipse IDE)

4. By reading this post we have actually assumed you are an advanced and intelligent developer..

Steps 

1. Have your external Checkstyle configuration file in hand. See http://java.sg/allow-project-specific-settings-in-checkstyle-plugin/

2. Locate and open your pom.xml (Project Object Model)

3. Insert the following code snippet into your plugins.

<project>
  ...
  <build>
    ...
    <plugins>
    ...
      <plugin>
        <groupId>org.apache.maven.plugins</groupId>
        <artifactId>maven-checkstyle-plugin</artifactId>
        <version>2.8</version>
        <configuration>
          <configLocation>C:\checkstyle-javasg.xml</configLocation>
        </configuration>
      </plugin>
    </plugins>
    ...
  </build>
  ...
</project>

Substitute configLocation with your own configuration file. In addition, this value may be a URL, File, or build classpath resource reference.

4. Add the checkstyle:check goal into your Maven task.

Go to Project > Run Configurations

Browse to your Maven build configuration, add “checkstyle:check” to your goals.

Apply and run.

Note: If you are running this off the command line, this would suffice:

$mvn checkstyle:check clean package

Checkstyle stops me from continuing with the violation:

[INFO] Scanning for projects...
[INFO]
[INFO] ------------------------------------------------------------------------
[INFO] Building hms-web 0.0.1-SNAPSHOT
[INFO] ------------------------------------------------------------------------
[INFO]
[INFO] --- maven-checkstyle-plugin:2.8:check (default-cli) @ hms-web ---
[INFO]
[INFO] There are 1 checkstyle errors.
[INFO] ------------------------------------------------------------------------
[INFO] BUILD FAILURE
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 2.529s
[INFO] Finished at: Mon Nov 07 14:53:51 SGT 2011
[INFO] Final Memory: 19M/64M
[INFO] ------------------------------------------------------------------------

Now, your codes are automatically checked by checkstyle. Checkstyle fails with an error and will not allow Maven to continue with the rest of the goals until you have rectified the Checkstyle violations. :)

In a later tutorial, i will post how Checkstyle may be integrated into Jenkins (Fork of Hudson).

Reference

Using a Custom Checkstyle Checker Configuration