How can i incorporate preprocessing into a service class, will adding them as regular method calls have drastic effects?

[abhikvarma]

I am making an API service where the resource, service and repository classes each return Unis/Multis.

In the service class i want to preprocess the API request data and then continue and then call the repository which will make a DB call. (i'm loosely following this guide: https://quarkus.io/guides/reactive-sql-clients).
I need to do the preprocessing, since that generates the query for the repository.

From what i understand I can either add the preprocessing method as a regular method call before calling the Repository like so:

public Uni<ResponseData> getData(DataObject obj) {

        String query = somePreprocessing(obj);

        return dataRepository.runQuery(query).collect().first()
                .onItem().transform(this::From);
    }

Or I could add it in the mutiny chain like so:

public Uni<ResponseData> getData(DataObject obj) {
        
        return Uni.createFrom().item(obj).onItem().transform(this::someProcessing)
                .onItem().transformToUni(query -> dataRepository.runQuery(query).collect().first())
                .onItem().transform(this::From);
    }

I just wanted to understand if there are any performance differences between the two approaches. Also, is there a better way to approach this?

[jponge]

Your mileage varies but both are very sound approaches 😉

Assuming somePreprocessing isn't doing any I/O work then I'd go with the first variant as it results in a simpler pipeline.
That being said the second variant is totally fine, it just allocates a few more objects with the initial Uni object creation and transformToUni step.

For most workloads you shouldn't see any throughput / latency difference, really.