Generate Uni from Multi response of database after applying business logic

[abnayak]

Hi,
I'm stuck at converting a very simple imperative code to reactive pattern.

Inside a rest function I'm making a reactive Postgres Db call which is returning a Multi. My intention is to run a complex business logic on Multi and return a new Uni based on the output of the business logic.

@GET
public Uni<HashMap<String, String>> get() {
    Multi<Object1> objects = DB.getAll(dbClient);

    Uni<HashMap<String, String>> response; // Not sure how to initialize this object without any value
    
    List<Object1> result = new ArrayList<>();
    objects.subscribe().with(
    object -> result.add(object),
    failure -> System.out.println("Failed with " + failure),
    () -> {
        // Business logic operate on result list
        // Update Uni response object
    });

    return response; // This should contain the output of the business logic
}

[cescoffier]

You need to collect the items into a Map.
See https://smallrye.io/smallrye-mutiny/guides/collecting-items#collecting-items-into-a-map.

In the end, you will have something like:

Multi<Object1> objects = DB.getAll(dbClient);
return Uni<Map<String, String>> uni =
        multi.collect()
                .asMap(item -> getUniqueKeyForItem(item)); // Put the computed key and the item to the Map

[abnayak]

@cescoffier Thanks for responding to my question.
My requirement is not a simple conversion of Multi element to map of Uni. My requirement is to run a business logic (100 LOC) to convert the Multi to a HashMap and at the end, I want to return the HashMap as Uni to down stream.