6.20 resource

'resource' is used for adding subclasses of org.restlet.resource.Resource to the routing.

Both org.restlet.resource.Resource and org.restlet.Restlet (as supported by the restlet routing instruction) allow to implement code to handle a request. Resource is different from Restlet in that it is:

• a higher-level API
• a new instance is created for each request, so Resource's don't need to be thread-safe

Typically the Restlet class will be used for more system/infrastructure-level work, while the Resource class should be used for everyday resource implementation work. An alternative for Resource is the JAX-RS API.

Parameters

(There are parameters available to implement resources inline in the routing using closures, but we recommend using ofClass/ofBean instead)

Example

The following example of a Resource implementation is stolen from the Restlet project:

package org.restlet.example.book.restlet.ch4;
import org.restlet.Context;
import org.restlet.data.MediaType;
import org.restlet.data.Request;
import org.restlet.data.Response;
import org.restlet.resource.Representation;
import org.restlet.resource.Resource;
import org.restlet.resource.ResourceException;
import org.restlet.resource.StringRepresentation;
import org.restlet.resource.Variant;

public class HelloWorldResource extends Resource {

    public HelloWorldResource() {
        // A default constructor is required in this case.
    }

    public void init(Context context, Request request,Response response) {
        super.init(context, request, response);
        // Declare all kind of representations supported by the resource
        getVariants().add(new Variant(MediaType.TEXT_PLAIN));
    }

    @Override
    public Representation represent(Variant variant) throws ResourceException {
        Representation representation = null;
        // Generate the right representation according to the variant.
        if (MediaType.TEXT_PLAIN.equals(variant.getMediaType())) {
            representation = new StringRepresentation("hello, world",
                    MediaType.TEXT_PLAIN);
        }
        return representation;
    }
}

It is attached to a router as follows:

router {
  resource(uri: "/helloworld",
           ofClass: "org.restlet.example.book.restlet.ch4.HelloWorldResource")
}