Hi, i need to execute meterService.incrementExitRequests(“online”) always, no matter if there is an ...

# arrow

[Jorge Bo]

Hi, i need to execute meterService.incrementExitRequests(“online”) always, no matter if there is an error. Is there anything in arrow that works like a finally clause? Not sure if it is the correct approach.

either<ReservationError, Unit> {
    //do some logic
}.mapLeft {
    meterService.incrementExitError("online")
    it
}.map {
    meterService.incrementExitRequests("online")
}

[phldavies]

You may be after guaranteeCase or bracketCase

[simon.vergauwen]

Interesting 🤔 both guaranteeCase or bracketCase would work for this, but it's actually meant for other things.

That being said guaranteeCase and bracketCase (and Resource) signal ExitCase.Cancelled when calling bind() on Either.Left.

Why not just use also?

either<ReservationError, Unit> {

}.also {
  meterService.incrementExitRequests("online")
}

[simon.vergauwen]

guaranteeCase or guarantee would make more sense to me if you'd do something like this.

either {
  guarantee({
    Either.Left("error").bind()
  }) { println("I always run") }
}

[Jorge Bo]

makes sense i’ll grive it a try