Questions: How to combine multiple UseCase?

[rommansabbir]

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Scenario:

• I have 3 UseCase to perform 3 different API Request.
• Based on the 3 UseCase response I need to combine them all according to the business logic.

Right now, I'm doing it by calling the 1st UseCase, then based on response, then another & so on.

So, how can I combine/zip them all in a single request or chain them one by one in a proper way?

[pankajpy]

This can be solved by Coroutines, Async and Await

• Async and Launch is the coroutine builder, Launch coroutine builder returns a job but async coroutine builder returns an instance of Deferred.
• We can use that Deferred value by invoking its await function

CoroutineScope(Main){ val stock1 = async(IO){ getStock1() // Api Call }val stock2 = async(IO){ getStock2() // Api Call }val total = stock1.await() + stock2.await() Log.i(“total”, total) }

• This is how we use async and await to get data from different data sources parallel and combined the result

On Thu, May 20, 2021 at 7:38 PM Romman Sabbir @.***> wrote:

Scenario:

• I have 3 UseCase to perform 3 different API Request.
• Based on the 3 UseCase response I need to combine them all according to the business logic.

Right now, I'm doing it by calling the 1st UseCase, then based on response, then another & so on.

So, how can I combine/zip them all in a single request or chain them one by one in a proper way?

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Thanks, Pankaj

[rommansabbir]

@pankajpy actually, I'm talking about how to merge/combine multiple UseCase into one. Yes, I know how to merge multiple API calling using Coroutine but UseCase is missing in this scenario.

[lrnrzg]

Have a try to combine response in the Repository layer and then pass the Repository to a new UseCase.

[rommansabbir]

@ZhuSniffsTheRose Yes got your point. But the scenario is:

• Have 3 Different Repository for Different Purpose
• Have 3 Different Use Case for 3 Different Purpose

Now, I can call all required api one by one in a single use by adding their dependency, but I want to combine merge/combine multiple UseCase into one.