@PathParam and PathSegments

The specification has a very simple abstraction for examining a fragment of the URI path being invoked on  javax.ws.rs.core.PathSegment:

public interface PathSegment {

    /**
     * Get the path segment.
     * <p>
     * @return the path segment
     */
    String getPath();
    /**
     * Get a map of the matrix parameters associated with the path segment
     * @return the map of matrix parameters
     */
    MultivaluedMap<String, String> getMatrixParameters();
    
}

You can have Resteasy inject a PathSegment instead of a value with your @PathParam.

   @GET
   @Path("/book/{id}")
   public String getBook(@PathParm("id") PathSegment id) {...}

This is very useful if you have a bunch of @PathParams that use matrix parameters.  The idea of matrix parameters is that they are an arbitrary set of name-value pairs embedded in a uri path segment.  The PathSegment object gives you access to theese parameters. See also MatrixParam.

A matrix parameter example is:

GET http://host.com/library/book;name=EJB 3.0;author=Bill Burke

The basic idea of matrix parameters is that it represents resources that are addressable by their attributes as well as their raw id.