Hands-On Microservices with Kotlin

Publishing multiple objects

Reactor provides a class to create a publisher that will return from 0 to an undetermined number of elements; that class is named Flux.

To create a simple Flux, we can just do:

val customerFlux = Flux.fromIterable(listOf(Customer(1,"one"), Customer(2, "two")))

Or, we can use the adequate Kotlin version:

val customerFlux =  listOf(Customer(1,"one"), Customer(2, "two")).toFlux()

Mono can be used when we only need to return one result in our publisher, whereas Flux can be used for 0 to N including 1, but if we are going to return just 1, it is preferable to use Mono instead of Flux since it is more optimal for that usage.