How can I combine the values from two publishers that are dependent on eachother?

Question

I have the following methods

class A -> Flux<A> getAllA();
class B -> Mono<B> getB(A a);
class C -> Mono<C> getC(A a, B b)

Now Im trying to achieve the following using a Reactive Stream:

1. Retrieve all A objects
2. Create object B for every A
3. Create object C for every pair A,B

Anyone know what this would look like? I came up with the solution below but was hoping there is some more elegant approach.

getAllA()
.map(a -> new Tuple2<A, B>(a, getB(a)))
.flatMap(t -> getC(t.getT1(), t.getT2()))

Answer 1

This is simple as:

final Flux<C> flux = getAllA()
    .flatMap(
        a -> getB(a)
            .flatMap(
                b -> getC(a, b)
            )
    );

No need for Tuples at all. Behind the scenes the compiler will generate the necessary invokedynamic bytecode and LambdaMetafactory will do some heavy lifting for us to pass a to getC(a, b).