How to do Basic Authentication of a resource in Dropwizard

I believe I have basic authentication working but I'm not sure how to protect resources so that they can only be accessed when the user is signed in.

public class SimpleAuthenticator implements Authenticator<BasicCredentials, User> {
    UserDAO userDao;

    public SimpleAuthenticator(UserDAO userDao) {this.userDao = userDao;}

    @Override
    public Optional<User> authenticate(BasicCredentials credentials) throws AuthenticationException    
    {
        User user = this.userDao.getUserByName(credentials.getUsername());
        if (user!=null &&
                user.getName().equalsIgnoreCase(credentials.getUsername()) &&
                BCrypt.checkpw(credentials.getPassword(), user.getPwhash())) {
            return Optional.of(new User(credentials.getUsername()));
        }
        return Optional.absent();
    }
}

My Signin resource is like this:

@Path("/myapp")
@Produces(MediaType.APPLICATION_JSON)
public class UserResource {
    @GET
    @Path("/signin")
    public User signin(@Auth User user) {
        return user;
    }
}

And I sign the user with:

~/java/myservice $ curl -u "someuser" http://localhost:8080/myapp/signin
Enter host password for user 'someuser':
{"name":"someuser"}

Question

Let's say the user signs in from a browser or native mobile app front end using the /myapp/signin endpoint. How then can I protect another endpoint, say, /myapp/{username}/getstuff which requires a user to be signedin

@GET
@Path("/myapp/{username}/getstuff")
public Stuff getStuff(@PathParam("username") String username) {
    //some logic here
    return new Stuff();
}