Spring different implementations of one service in controller depended on authenticated user's authority

Question

I have a ReservationController in my spring project that injects ReservationService. Here is my ReservationController Class

I have two implementations of ReservationService: ReservationServiceImpl and ReservationDoublePriceServiceImpl. Here is my ReservationService1 Class

Here is my ReservationService2 Class

I want ReservationController to choose service's implementation depended on authenticated user's authority(If authority is User choose ReservationServiceImpl and if authority is DoublePriceUser choose ReservationDoublePriceServiceImpl).

Can someone suggest how can I do this?

P.S I have done with application.properties parameter and qualifiers, but it only makes me an opportunity to choose only one of my service implementations.

How can I choose service beans in Runtime?

Answer 1

There are plenty ways to do that, I'd suggest to start with something simple. Add a supports(Set<String> authorities) method in your ReservationService interface, and the implementation itself will tell if it supports the authorities passed (check if contains the role).

Create a Factory class, which will be used to choose the right implementation for you, like so:

@Component
public class ReservationServiceFactory {

    private final List<ReservationService> services;

    public ReservationService getService(Set<String> authorities) {
        for (ReservationService service : this.services) {
            if (service.supports(authorities)) {
                return service;
            }
        }
        throw new IllegalArgumentException("Could not resolve ReservationService for authorities " + authorities);
    }

}

public interface ReservationService {
    // add this method in your ReservationService interface
    boolean supports(Set<String> authorities);
}

And, in your controller you can do something like:

@GetMapping
public void anyMethod(/*inject the authentication object*/Authentication authentication) {
    this.reservationServiceFactory.getService(authentication.getAuthorities()).doSomething();
}