How do I avoid reaching the .or() in this code?

Question

static final Function<Bill,Optional<LocalDate>> toDateOfInjury = b -> toClaim.andThen(opt -> opt.map(Claim::getDatInjuryDate)).apply(b); 

public static final Supplier<Optional<String>> emptyStrOpt = Optional::empty;

static final Function<Bill,Optional<String>> dateOfInjuryNotNull = b ->
            toDateOfInjury.andThen(
                    opt -> opt.flatMap(doi -> emptyStrOpt.get())
                            .or(() -> Optional.of("No date of injury"))).apply(b);

In a unit test, this always returns the "No date of injury" optional. I assume it is because the empty result of flatMap triggers it. This is what I want:

null dateOfInjury: Optional.of(".....")
non-null dateOfInjury: Optional.empty()

What is `toDateOfInjury`? Please provide a complete example. — marstran, Jan 14 '22 at 17:45
I'm not really sure what you are trying to do here, but there is a probably a better more clear way to code this. — RobOhRob, Jan 14 '22 at 17:49
Your code essentially performs `opt.flatMap(doi -> Optional::empty)`, which always triggers the `or` part. What did you expect? — f1sh, Jan 14 '22 at 17:49
`opt.map(doi -> Optional.empty()).orElseGet(() -> Optional.of("..."))` — shmosel, Jan 14 '22 at 17:53
@shmosel yes this did the trick. I will award you the answer if you post this. — FaraBara, Jan 14 '22 at 18:14
or `opt.isPresent()? Optional.empty(): Optional.of("No date of injury")` — Holger, Jan 17 '22 at 10:28

score 0 · Answer 1 · answered Jan 14 '22 at 17:52

0

This looks like you want a simple null check. What about

return dateOfInjury==null?Optional.empty():Optional.of("No date of injury");

answered Jan 14 '22 at 17:52

f1sh

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How do I avoid reaching the .or() in this code?

1 Answers1