Project Reactor: Sum two Mono<Integer> without blocking

Question

Suppose that we have:

Mono<Integer> int1 = Mono.just(1) and Mono<Integer> int2 = Mono.just(10). I would like get the sum of these two integer without blocking.

In the blocking way I would do this: Mono<Integer> result = Mono.just(int1.block() + int2.block())

Thanks in advance!

Answer 1

Try zip:

Mono<Integer> int1 = Mono.just(1); //or any other mono, including lazy one
Mono<Integer> int2 = Mono.just(10); //same


Mono<Integer> sum = Mono.zip(
    int1, int2,
    //zip defaults to producing a Tuple2
    //but for the 2 args version you can provide a BiFunction
    (a, b) -> a + b
);

//if you want to verify, eg. in a test:
StepVerifier.create(sum)
    .expectNext(11)
    .verifyComplete();