Dispatch a CompletionStage / CompletableFuture API service in a Reactive REST GET endpoint with Quarkus/Mutiny

Question

After implementing a Reactive REST GET endpoint with Quarkus / Mutiny using a callback structure and checking the variant with a blocking service i finally played with a CompletionStage / CompletableFuture API version;

How do i call a CompletionStage / CompletableFuture API service from my Reactive REST GET endpoint with Quarkus/Mutiny

Answer 1

Again it turned out to be quite simple (although the underlying idea may be more complex);

The ServiceResource just forwards the call to the Service.

MyRequestService creates a MyJsonResultCompletableFuture (CompletableFuture implements CompletionStage) and delivers this to the Mutiny Uni with method completionStage(). Another possibility would be using;

Uni.subscribe().asCompletionStage()

The resulting Uni is returned to the ServiceResource.

Finally MyJsonResultCompletableFuture blocks the call from MyReactiveServiceResource / MyRequestService waiting for a completionStage. Method ready() accomplish this stage and returns the MyJsonResult to Mutiny (acting like some kind of callback).