public interface SCIMServiceStub {

    @RequestLine("GET /Users/{id}")
    SCIMUser getUser(@Param("id") String id);

    @RequestLine("GET /Groups?filter=displayName+Eq+{roleName}")
    SCIMGroup isValidRole(@Param("roleName") String roleName);

}

/Groups?filter=displayName+Eq+{roleName}"

@RequestLine("GET /Groups?filter={roleName}")
String isValidRole(@Param(value = "roleName", expander = PrefixExpander.class) String roleName);

static final class PrefixExpander implements Param.Expander {
    @Override
    public String expand(Object value) {
        return "displayName+Eq+" + value;
    }
}

@GetMapping("user")
    String getUser(@SpringQueryMap User user);

public class User {
    private String name;
    private int age;
    ...
}