I have tested a lot of async frameworks in a lot of languages and I like ReactiveX for Java (RxJava, Reactor) the most. // process1 does nothing and takes

I have tested a lot of async frameworks in a lot of languages and I like ReactiveX for Java (RxJava, Reactor) the most. // process1 does nothing and takes 20s to complete // if cancelled, it will print a message private Mono<Void> process1() { return Mono .just(new Object()) .delayElement(Duration.ofSeconds(20)) .then() .doOnCancel(() -> log.info("I have just been canceled")); } // assume it does the same as process1 private Mono<Void> process2() { ... } private Mono<Object> cancellationSignal() { return Mono .just(new Object()) .delayElement(Duration.ofSeconds(10)) .doOnNext(n -> log.info("oops, sending cancellation")); } // executes process1, then process2 // if cancellationSignal happens before they finish they will be safely cancelled, you will only receive message from process1 private Mono<Void> compositeSequential() { return process1() .then(process2()) // timeout() is just one way to cause cancellation (in this case on an arbitrary signal) .timeout(cancellationSignal()); } // executes both processes concurrently // you will receive messages from both processes as they are both getting the cancellation private Mono<Void> compositeConcurrent() { return Flux .just(process1(), process2()) .flatMap(identity()) .then() .timeout(cancellationSignal()); }