Don't let those ruby devs have all the fun, with a simple filter you can have sass in your java too.

Add this to your web.xml

<filter>
    <filter-name>SassCompiler</filter-name>
    <filter-class>com.sass_lang.SassCompilingFilter</filter-class>
</filter>

<filter-mapping>
    <filter-name>SassCompiler</filter-name>
    <url-pattern>*.css</url-pattern>
</filter-mapping>

Put your sass templates in WEB-INF/sass and each request for a css file will regenerate as needed.

Maven

Since getting stuff in central is a PITA, add the following to your pom.xml

<repositories>
    <repository>
        <id>sass-java</id>
        <url>http://sass-java.googlecode.com/svn/repo/</url>
    </repository>
</repositories>

<dependencies>
    <dependency>
        <groupId>com.sass-lang</groupId>
        <artifactId>sass-java</artifactId>
        <version>3.1.1.4</version>
    </dependency>
</dependencies>

Ant

Download the jar with depenencies

##Config

Configuration is done through filter init parameters

• templateLocation - the location where the sass templates will be found (default WEB-INF/sass)
• cssLocation - the location where the sass templates will be compiled to (default stylesheets)
• cacheLocation - the location that sass will use for compile caching (default WEB-INF/.sass-cache)
• cache - turn caching on/off (default true)
• onlyRunWhenKey - the system property or environment variable to check to see if sass compilation should run, use this to turn sass generation off in production
• onlyRunWhenValue - the corresponding value to check to see if sass compilation should run

You probably only want the css generation to run in development mode and then commit the generated css to source control. This is achieved by the onlyRunWhenKey and onlyRunWhenValue filter init parameters.

<filter>
    <filter-name>SassCompiler</filter-name>
    <filter-class>com.sass_lang.SassCompilingFilter</filter-class>
    <init-param>
        <param-name>onlyRunWhenKey</param-name>
        <param-value>RUNTIME_ENVIRONMENT</param-value>
    </init-param>
    <init-param>
        <param-name>onlyRunWhenValue</param-name>
        <param-value>local</param-value>
    </init-param>
</filter>

With this configuration the filter will check a system property or environment variable called RUNTIME_ENVIRONMENT and only run the sass compilation if that value is equal to local

##Try it out

1. git clone https://github.com/darrinholst/sass-java.git
2. cd sass-java
3. mvn jetty:run
4. wait for maven to download the internet
5. open http://localhost:8080/sass-java
6. change src/test/sample-webapp/WEB-INF/sass/application.scss
7. repeat step 5
8. be amazed