Pr0methean

5y

java.util.Optional.or, orElse and orElseGet should really have their signatures changed so they can widen the type. For example, `Optional<T> or(Supplier<? extends Optional<? extends T>> supplier)` should really be `<U, S super T & U> Optional<S> or(Supplier<? extends Optional<? extends U>> supplier)`

Then we could eliminate the following unchecked cast:
```
public static double getOrNan(Optional<? extends Number> optionalNumber) {
return ((Optional<Number>)optional).getOrElse(Double.NaN).doubleValue();
}
```

rant

optional

java

generics

Ranter

Comments

1

tkdmatze

443

5y

hmm

public static double getOrNan(Optional<? extends Number> optionalNumber) {
return optionalNumber.map(Number::doubleValue).orElse(Double.NaN);
}
0

Pr0methean

14

5y

@tkdmatze That works, but it's more unboxing and re-boxing of the double. How much of that can the C2 compiler optimize out?

Related Rants

devRant © 2021 Hexical Labs LLC
Privacy Policy | Terms of Service