Using Freemarker from Mule transformer

[athieme]

I am having problems using a templating engine like Freemarker or Velocity from within a Mule deployed app. I've had similar ClassNotFoundExceptions using both Freemarker and Velocity. I suspect there's some magic Mule or Maven dependency problem, but I'm not sure what. As an aside, I first tried using Velocity and had a ClassNotFoundException (org.apache.velocity.exception.VelocityException), too. And, I followed the steps outlined in David Dossot's Mule In Action example (http://code.google.com/p/muleinaction/source/browse/branches/mule-3/chapter05/velocity-transformer/?r=483).

Using Freemarker as the example, when I attempt to deploy my application to Mule, I get the following Exception.

Caused by: java.lang.ClassNotFoundException: freemarker.cache.TemplateLoader

at java.net.URLClassLoader$1.run(URLClassLoader.java:202)

at java.security.AccessController.doPrivileged(Native Method)

at java.net.URLClassLoader.findClass(URLClassLoader.java:190)

at java.lang.ClassLoader.loadClass(ClassLoader.java:306)

at java.lang.ClassLoader.loadClass(ClassLoader.java:247)

... 63 more

During the deployment of the app, I see the freemarker-2.3.19.jar loaded. See below.

INFO  2012-05-25 22:50:00,890 [Mule.app.deployer.monitor.1.thread.1] org.mule.module.launcher.MuleApplicationClassLoader: [dartmouth-server] Loading the following jars:

=============================

file:/Users/athieme/mule-standalone-3.2.1/apps/dartmouth-server/lib/aopalliance-1.0.jar

file:/Users/athieme/mule-standalone-3.2.1/apps/dartmouth-server/lib/cglib-nodep-2.1_3.jar

file:/Users/athieme/mule-standalone-3.2.1/apps/dartmouth-server/lib/commons-logging-1.1.1.jar

file:/Users/athieme/mule-standalone-3.2.1/apps/dartmouth-server/lib/dartmouth-common.jar

file:/Users/athieme/mule-standalone-3.2.1/apps/dartmouth-server/lib/freemarker-2.3.19.jar

file:/Users/athieme/mule-standalone-3.2.1/apps/dartmouth-server/lib/guava-r09.jar

file:/Users/athieme/mule-standalone-3.2.1/apps/dartmouth-server/lib/jaxb-api-2.2.5.jar

file:/Users/athieme/mule-standalone-3.2.1/apps/dartmouth-server/lib/jaxb2-basics-0.6.0.jar

file:/Users/athieme/mule-standalone-3.2.1/apps/dartmouth-server/lib/jaxb2-basics-runtime-0.6.0.jar

file:/Users/athieme/mule-standalone-3.2.1/apps/dartmouth-server/lib/jaxb2-basics-tools-0.6.0.jar

file:/Users/athieme/mule-standalone-3.2.1/apps/dartmouth-server/lib/jedis-2.0.0.jar

file:/Users/athieme/mule-standalone-3.2.1/apps/dartmouth-server/lib/spring-asm-3.1.1.RELEASE.jar

file:/Users/athieme/mule-standalone-3.2.1/apps/dartmouth-server/lib/spring-context-support-3.1.1.RELEASE.jar

file:/Users/athieme/mule-standalone-3.2.1/apps/dartmouth-server/lib/spring-core-3.1.1.RELEASE.jar

file:/Users/athieme/mule-standalone-3.2.1/apps/dartmouth-server/lib/spring-data-redis-1.0.0.RC1.jar

file:/Users/athieme/mule-standalone-3.2.1/apps/dartmouth-server/lib/spring-tx-3.1.0.RC1.jar

=============================

It's freemarker-2.3.19.jar that contains freemarker.cache.TemplateLoader. See below.

11:28 PM dartmouth> jar tvf ~/mule/apps/dartmouth-server/lib/freemarker-2.3.19.jar |grep "freemarker.cache.TemplateLoader"

   445 Thu Mar 01 01:10:00 EST 2012 freemarker/cache/TemplateLoader.class

11:28 PM dartmouth> 

In my Mule/Spring configuration, I have the following.

<spring:bean id="freemarkerConfig" class="org.springframework.ui.freemarker.FreeMarkerConfigurationFactoryBean">

      <spring:property name="templateLoaderPath" value="classpath:com/athieme/"/>

    </spring:bean>

As a separate test, I created a very small, non-Mule Maven project that includes the required dependancies to inject the Freemarker Configuration object. Here's that pom.xml. When I run code from this project, Freemarker is called correctly.

<?xml version="1.0" encoding="UTF-8"?>

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"

         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">

    <modelVersion>4.0.0</modelVersion>

    <groupId>com.athieme</groupId>

    <artifactId>simple-spring-maven</artifactId>

    <version>1.0.0-SNAPSHOT</version>

    <packaging>jar</packaging>

    <properties>

        <org.springframework>3.1.1.RELEASE</org.springframework>

    </properties>

    <dependencies>

        <dependency>

            <groupId>org.springframework</groupId>

            <artifactId>spring-core</artifactId>

            <version>${org.springframework}</version>

       </dependency>

        <dependency>

            <groupId>org.springframework</groupId>

            <artifactId>spring-context</artifactId>

            <version>${org.springframework}</version>

       </dependency>

       <dependency>

            <groupId>org.springframework</groupId>

            <artifactId>spring-context-support</artifactId>

            <version>${org.springframework}</version>

        </dependency>

       <dependency>

           <groupId>org.freemarker</groupId>

           <artifactId>freemarker</artifactId>

           <version>2.3.19</version>

        </dependency>

    </dependencies>

</project>

Here's (basically) the Java code to call Freemarker; although, Mule never gets this far because the Mule/Spring config never loads completely.

final StringWriter result = new StringWriter();

final Template template = configuration.getTemplate("password.ftl");

final Message message = new Message();

java.util.Map map = new java.util.HashMap();

map.put("message", message);

template.process(map, result);

String str = result.toString();

System.out.println(str);

Alex Thieme

[hidden email]

508-361-2788

In

Alex Thieme

[hidden email]

508-361-2788

In

[athieme]

This question was answered (offline) by David Dossot (see below). Copying the freemarker jar into mule/lib/user folder resolved the class loading problem.

On May 28, 2012, at 12:29 PM, David Dossot wrote:

Two things that came to mind:

• Deploying on iON might actually be easier because it is said that: "Any libraries that are packaged in your mule application lib folder will be made available on the classpath to your application at run time" (see http://www.mulesoft.org/documentation/display/ION/Developing+an+iON+Application#DevelopinganiONApplication-PackagingThirdPartyLibraries). This probably means the libs will be available in the highest Mule classloader. And actually, from my experience deploying on iON, I've indeed noticed that Mule is able to use such libs flawlessly so I suspect the iON deployment to be different from the local standalone one.
• If I understand this correctly http://www.mulesoft.org/documentation/display/MULE3USER/Classloader+Control+in+Mule#ClassloaderControlinMule-ClassloadingOverride%2FBlockingPathDiagram you should be able to redirect the Mule parent classloader to look for Velocity/FreeMarker classes in the child classloader (ie your app classloader). Worth a try.

Cheers,

D.