HATEOAS - RESTful Java with JAX-RS 2.0 - page 154

public public UriBuilder getRequestUriBuilder ();

public

public URI getAbsolutePath ();
public

public UriBuilder getAbsolutePathBuilder ();
public

public URI getBaseUri ();
public public UriBuilder getBaseUriBuilder ();

For example, let's say you have a JAX-RS service that exposes the customers in a customer
database. Instead of having a base URI that returns all customers in a document, you want to
embed previous and next links so that you can navigate through subsections of the data-
base (I described an example of this earlier in this chapter). You will want to create these link
relations using the URI to invoke the request:

@Path ( "/customers" )
public public class class CustomerService CustomerService {

@GET
@Produces ( "application/xml" )
public

public String getCustomers ( @Context UriInfo uriInfo ) {

UriBuilder nextLinkBuilder = uriInfo . getAbsolutePathBuilder ();
nextLinkBuilder . queryParam ( "start" , 5 );
nextLinkBuilder . queryParam ( "size" , 10 );
URI next = nextLinkBuilder . build ();

... set up the rest of the document ...

}

To get access to a UriInfo instance that represents the request, we use the
@javax.ws.rs.core.Context annotation to inject it as a parameter to the JAX-RS resource
method getCustomers() . Within getCustomers() , we call ur-
iInfo.getAbsolutePathBuilder() to obtain a preinitialized UriBuilder . Depending on
how this service was deployed, the URI created might look like this:

http: //example.com/jaxrs/customers?start=5&size=10

UriInfo also allows you to relativize a URI based on the current request URI.

public public URI relativize ( URI uri );

So, for example, if the current request was http://localhost/root/a/b/c and you passed
a/d/e as a parameter to the relativize() method, then the returned URI would be ../../
d/e . The root segment is the context root of your JAX-RS deployment. Relativization is
based off of this root.