Brief exploration into what it takes to do vendor extensions in JAX-RS.

VendorJsonProvider.java

package com.yammer.testvendor;

import com.yammer.dropwizard.jersey.JacksonMessageBodyProvider;
import com.yammer.dropwizard.json.Json;

import javax.ws.rs.Consumes;
import javax.ws.rs.Produces;
import javax.ws.rs.core.MediaType;
import java.lang.annotation.Annotation;
import java.lang.reflect.Type;
import java.util.regex.Pattern;

@Produces("application/*")
@Consumes("application/*")
public class VendorJsonProvider extends JacksonMessageBodyProvider {
    private static final String TYPE = "application";
    private static final Pattern SUBTYPE_PATTERN = Pattern.compile("vnd\\..*\\+json");

    public VendorJsonProvider(Json json) {
        super(json);
    }

    @Override
    public boolean isReadable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
        return mediaType.getType().equals(TYPE) &&
                SUBTYPE_PATTERN.matcher(mediaType.getSubtype()).matches() &&
                super.isReadable(type, genericType, annotations, MediaType.APPLICATION_JSON_TYPE);
    }

    @Override
    public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
        return mediaType.getType().equals(TYPE) &&
                SUBTYPE_PATTERN.matcher(mediaType.getSubtype()).matches() &&
                super.isWriteable(type, genericType, annotations, MediaType.APPLICATION_JSON_TYPE);
    }
}

VendorResource.java

package com.yammer.testvendor;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.Produces;

@Path("/vendor")
@Produces("application/vnd.myvendor+json")
public class VendorResource {
    @GET
    public Vendor get() {
        return new Vendor(1, "yammer");
    }
}