class SessionService {

    public SessionId getSessionIfItExists(SessionId sessionId) {
        if (sessionRepository.sessionExists(sessionId)) {
            return sessionId;
        }

        throw new SessionNotFoundException(sessionId);
    }

    @Inject public  SessionService(SamlEngineProxy samlEngineProxy,
                          TransactionsConfigProxy configProxy,
                          AuthnRequestFromTransactionHandler authnRequestHandler,
                          SessionRepository sessionRepository);

}