How can we compose 3 or more completablefutures while maintaining all the results

Question

I have 3 services which I want to chain

CompletableFuture<String> serviceA
CompletableFuture<String> serviceB(String resultFromA)
CompletableFuture<String> serviceC(String resultFromA, String resultFromB)

If I use thenCompose, I can't seem to maintain the first result

ie

serviceA.thenCompose(a -> serviceB(a))
        .thenCompose(b -> serviceC(a, b));  // a is lost

If I use CompletableFuture.allOf(), I don't see that it allows chaining - running in sequence and passing results.

I am going to modify serviceB, so that it returns a Pair, or some composite object, but is there a better way?

Answer 1

serviceA.thenCompose(a -> serviceB(a).thenCompose(b -> serviceC(a, b)));