Based on the recommendation by APIGEE in their RESTful API Design blog post I wish to implement the fields query-string parameter to allow mobile application clients to restrict the content returned from a single RESTful API call. For example:
domain.site.com/rest/accounts/{id}?fields=name,id,age
If the fields parameter is omitted then a complete account resource will be returned. My question is how would I implement this on the server using Jersey (for example). Since Jersey makes it easy to return an Account POJO but I am unsure how to restrict the fields of the resulting JSON object based on the 'fields' query-string parameter.
There's not an automatic way to do it. Your service should load the entire object and then null out the fields you dont' want. Make sure the beans are annotated to ignore null fields in the json serialization and then return the object after you've modified it to remove the fields you dont' want.