JAX-RS Injection - RESTful Java with JAX-RS 2.0 - page 61

In this example, if our request was GET /cars/mercedes/e55/amg/year/2006 , the car
parameter would have a list of two PathSegments injected into it, one representing the e55
segment and the other representing the amg segment. We could then query and pull in matrix
parameters as needed from these segments.

Programmatic URI Information

All this à la carte injection of path parameter data with the @PathParam annotation is perfect
most of the time. Sometimes, though, you need a more general raw API to query and browse
information about the incoming request's URI. The interface javax.ws.rs.core.UriInfo
provides such an API:

public public interface interface UriInfo UriInfo {

public public String getPath ();

public public String getPath ( boolean boolean decode );

public public List < PathSegment > getPathSegments ();

public

public List < PathSegment > getPathSegments ( boolean boolean decode );

public public MultivaluedMap < String , String > getPathParameters ();

public

public MultivaluedMap < String , String > getPathParameters ( boolean boolean decode );

...
}

The getPath() methods allow you to obtain the relative path JAX-RS used to match the in-
coming request. You can receive the path string decoded or encoded. The getPathSeg-
ments() methods break up the entire relative path into a series of PathSegment objects. Like
getPath() , you can receive this information encoded or decoded. Finally, getPathPara-
meters() returns a map of all the path parameters defined for all matching @Path expres-
sions.

You can obtain an instance of the UriInfo interface by using the
@javax.ws.rs.core.Context injection annotation. Here's an example:

@Path ( "/cars/{make}" )
public public class class CarResource CarResource {

@GET
@Path ( "/{model}/{year}" )
@Produces ( "image/jpeg" )
public public Jpeg getPicture ( @Context UriInfo info ) {

String make = info . getPathParameters (). getFirst ( "make" );
PathSegment model = info . getPathSegments (). get ( 1 );
String color = model . getMatrixParameters (). getFirst ( "color" );

...