How to check if Mono is empty?

Question

I\'m developing a app with Spring Boot 2.0 and Kotlin using the WebFlux framework.

I want to check if a user id exits before save a transaction. I\'m stucked in a simple

Answer 1

We can use switchIfEmpty method for this

Below example, I'm checking if the user exists with email if not then add it

userRepository.findByEmail(user.getEmail())
                .switchIfEmpty(s -> {
                    user.setStatus("InActive");
                    String encodedPassword = DigestUtils.sha256Hex(user.getPassword());
                    user.setPassword(encodedPassword);
                    userRepository.save(user).subscribe();
                    s.onComplete();
                }).then(Mono.just(user));