Jersey JAX-RS and Freemarker

UPDATE

The example below uses sun specific packages. See here http://blogs.citytechinc.com/sjohnson/?p=32 for how to do it using jax-rs stuff only.


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I've been scratching around with various REST frameworks and I think I like Jersey. However, there's no native support out of the box for my fave templating superstar Freemarker.

So here's my first scratch at a ViewProcessor that supports Freemarker.

@Provider
@Singleton
public class FreemarkerViewProcessor implements ViewProcessor<Template> {

    private final Logger l = Logger.getLogger(FreemarkerViewProcessor.class);
    private final Configuration cfg = new Configuration();

    @Context
    public void setServletContext(final ServletContext context) {
        // TODO - all of these should be in freemarker.properties.
        cfg.setLocalizedLookup(false);
        cfg.setTemplateUpdateDelay(0);
        cfg.setTemplateLoader(new WebappTemplateLoader(context, "/WEB-INF/templates"));
    }

    public Template resolve(final String path) {
        try {
            return cfg.getTemplate(path);
        } catch (final IOException e) {
            return null;
        }
    }

    @SuppressWarnings("unchecked")
    public void writeTo(final Template template, final Viewable viewable, final OutputStream out) throws IOException {
        try {
            template.process((Map<String, Object>) viewable.getModel(), new OutputStreamWriter(out));
        } catch (final TemplateException e) {
            throw new IOException(e);
        }
    }
}

And here's how you use it...

@Path("/")
public class BananaResource {

    @GET
    @Produces(MediaType.TEXT_HTML)
    public Viewable getBanana() {
        final Map<String, Object> vars = new HashMap<String, Object>();
        vars.put("name", "banana");
        return new Viewable("/banana.ftl", vars);
    }
}