Using Velocity or XSLT Templates in Seam

[dhinojosa]

I am transporting over a web framework action over to a session bean to use in Seam. The webframework action transformed either a Velocity template or a XSLT into an email that I can send out. Now that my service is on the session bean instead of a web framework action, how do I get a velocity template or XSLT template into the session bean for transformation. Before as a web action I used to do something like this:

Properties properties = new Properties();
String realPath = servletContext.getRealPath("WEB-INF");
properties.put("file.resource.loader.path", realPath);
Velocity.init(properties);

This would retrieve all the velocity templates from the WEB-INF directory. Now there is no dependency of the WEB-INF or servletContext. Does anyone have any strategy for something like this?

[shane.bryzak]

Create your own response resource loader by extending org.apache.velocity.runtime.resource.loader.ResourceLoader, and override the getResourceStream() method. Then set the Velocity engine "service.resource.loader.class" property to point to your new resource loader class. Then you can use getClass().getResourceAsStream(<resource name goes here>) to load your templates.

[dhinojosa]

and what shall I put in getResourceAsStream() ?

[shane.bryzak]

The path to the file containing your Velocity template. So for example, if you're storing your templates in the WEB-INF directory and they have a .template extension, your getResourceStream() method would look like this:

public InputStream getResourceStream(String source)
 throws ResourceNotFoundException
{
 return getClass().getResourceAsStream(
 String.format("/WEB-INF/%s.template", source));
}

[dhinojosa]

Thanks for your help, but I don't think I can or should rely on /WEB-INF/. That way I can reuse those same beans that have non-web-based clients. I think the ultimate best solution could be a JMX setup so that we can get a velocity context injected into a stateless or stateful bean.


IOW, something like this

@Stateful
public class MySessionBean {

@Resource(name="apache/env/VelocityContext")
private VelocityContext velocityContext;

}

[shane.bryzak]

The template resources could come from anywhere; a directory in your application archive, db table, etc - your resource loader just has to load them from somewhere. Personally I'd use an application-scoped bean to wrap the velocity context, annotate it with @Startup and define a @Create method that initialises the velocity context and possibly loads and caches your templates.

If you want to expose it as an MBean then you'd have to write it as a JBoss service and provide a management interface, but I don't really see any advantage to doing this unless you have special requirements.