Red Hat Training

A Red Hat training course is available for Red Hat Fuse

Chapter 45. Returning Information to the Consumer

Abstract

RESTful requests require that at least an HTTP response code be returned to the consumer. In many cases, a request can be satisfied by returning a plain JAXB object or a GenericEntity object. When the resource method needs to return additional metadata along with the response entity, JAX-RS resource methods can return a Response object containing any needed HTTP headers or other metadata.

45.1. Return Types

The information returned to the consumer determines the exact type of object a resource method returns. This may seem obvious, but the mapping between Java return objects and what is returned to a RESTful consumer is not one-to-one. At a minimum, RESTful consumers need to be returned a valid HTTP return code in addition to any response entity body. The mapping of the data contained within a Java object to a response entity is effected by the MIME types a consumer is willing to accept.
To address the issues involved in mapping Java object to RESTful response messages, resource methods are allowed to return four types of Java constructs:
  • common Java types return basic information with HTTP return codes determined by the JAX-RS runtime.
  • JAXB objects return complex information with HTTP return codes determined by the JAX-RS runtime.
  • JAX-RS return complex information with a programmatically determined HTTP return status. The Response object also allows HTTP headers to be specified.
  • JAX-RS return complex information with HTTP return codes determined by the JAX-RS runtime. The GenericEnitity object provides more information to the runtime components serializing the data.