Conditional Behavior in project Reactor stack

Question

I need to create a method that gets data from external cache. If a data is found it does some processing otherwise it should do different processing. The method should return Mono

Mono<Void> myMethod() {
   return getDataFromCache()
             .flatMap(data -> processDataFromCache(data))
             .switchIfEmpty(Mono.defer(() -> doSomethingElse()));
}

The issue I'm having is, because processDataFromCache(data) return type is Mono<Void>, the switchIfEmpty part is always executed. Is there a way to do this differently?

Answer 1

If you cannot change the behavior of the processDataFromCache and doSomethingElse then you can connect them with some fake values coming after their successful execution:

Mono<Void> myMethod() {
   return getDataFromCache()
             .flatMap(data -> processDataFromCache(data).then("processed"))
             .switchIfEmpty(Mono.defer(() -> doSomethingElse().then("new")))
             .then();
}