Checkstyle Write your own checks

Understanding AST

AST Tree

RooT
-sibling
 |-child
 |-sibling
 |-sibling
-Sibling
-sibling
-Sibling

command to display AST Tree: 
java -classpath C:\checkstyle-5.6-all.jar com.puppycrawl.tools.checkstyle.gui.Main

command to run check for a sinlge class
java -classpath C:\checkstyle-5.6-all.jar com.puppycrawl.tools.checkstyle.Main -c checkstyle_test.xml SampleClass.java

command to run check using maven
mvn clean install -DgenerateReports=false checkstyle:checkstyle checkstyle:check



JUnit Testing CheckStyle
similar test provided at
http://opensourcejavaphp.net/java/checkstyle/com/puppycrawl/tools/checkstyle/BaseCheckTestSupport.java.html

client POM.xml

			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-checkstyle-plugin</artifactId>
				<version>2.9.1</version>
					<configuration>
		          		<configLocation>C:\checkstyle_test.xml</configLocation>
						<!--
						<configLocation>
						http://localhost:9080/sonar/profiles/export?format=checkstyle&amp;language=java&amp;name=test.checkstyle
						</configLocation>
						-->
		          	</configuration>
					<executions>
					  <execution>
						<id>checkstyle</id>
						<phase>prepare-package</phase>
						<goals>
						  <goal>checkstyle</goal>
						</goals>
					  </execution>
					  <execution>
						<id>checkstyle-check</id>
						<phase>verify</phase>
						<goals>
						  <goal>check</goal>
						</goals>
					  </execution>
					</executions>					
		          	<dependencies>
		          		<dependency>
		          			<groupId>my.checkstyle</groupId>
		          			<artifactId>my-checkstyle</artifactId>
		          			<version>1.0.0-SNAPSHOT</version>
		          		</dependency>
				<dependency>
			  <groupId>org.eclipse.equinox</groupId>
			  <artifactId>app</artifactId>
			  <version>1.0.0-v20070606</version>
			</dependency>
		          	</dependencies>
			</plugin>
			

Writing Check to parse non java files

Checkstyle_test.xml
=====================

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE module PUBLIC "-//Puppy Crawl//DTD Check Configuration 1.2//EN" "http://www.puppycrawl.com/dtds/configuration_1_2.dtd">
<module name="Checker">

		<module name="RegexpMultiline">
			<property name="format" value="(?i)script"/>
			<property name="fileExtensions" value="jsp,xml,html,js" />
			<property name="severity" value="warning" />
		</module> 
</module>

plugin for pom.xml
===========================

			<plugin>
				<groupId>org.apache.maven.plugins</groupId>
				<artifactId>maven-checkstyle-plugin</artifactId>
				<version>2.9.1</version>
					<configuration>
		          		<configLocation>C:\checkstyle_test.xml</configLocation>
						<!--
						<configLocation>
						http://localhost:9080/sonar/profiles/export?format=checkstyle&amp;language=java&amp;name=cde.checkstyle
						</configLocation>
						-->
						<sourceDirectory>${project.build.directory}</sourceDirectory>  
							
					<includes>**\/*.jsp, **\/*.java, **\/*.xml</includes>
		          	</configuration>
					<executions>
					  <execution>
						<id>checkstyle</id>
						<phase>prepare-package</phase>
						<goals>
						  <goal>checkstyle</goal>
						</goals>
					  </execution>
					  <execution>
						<id>checkstyle-check</id>
						<phase>verify</phase>
						<goals>
						  <goal>check</goal>
						</goals>
					  </execution>
					</executions>					
		          	<dependencies>
		          		<dependency>
		          			<groupId>my.checkstyle</groupId>
		          			<artifactId>my-checkstyle</artifactId>
		          			<version>1.0.0-SNAPSHOT</version>
		          		</dependency>
				<dependency>
			  <groupId>org.eclipse.equinox</groupId>
			  <artifactId>app</artifactId>
			  <version>1.0.0-v20070606</version>
			</dependency>
		          	</dependencies>
			</plugin>