I'm have a function which should return nothing (void ) or a String when some conditions are not met. I try this line Either.left(Void) private Either<Void,String> processOrReturnErrorMess...

I have an Try<Option<Foo>>. I want to flatMap Foo into a Bar, using it using an operation that can fail. It's not a failure if my Option<Foo> is an Option.none(), (and the Try was...

I have a couple of Vavr Either's and I want to invoke a function with the Right value for each of these Either's. For example: Either<MyError, String> either1 = .. Either<MyError, String&...

The expectation is derive 3 lists itemIsBoth, aItems, bItems from the input list items. How to convert code like below to functional style? (I understand this code is clear enough in an imperative ...

I have a list of objects. The object looks like this: public class Slots { String slotType; Visits visit; } public class Visits { private long visitCode; private String agendaCode; private ...

Could anyone please explain why this code: interface Lol { default Try<Seq<? extends Number>> lol() { return Try.of(List::empty); } } class LolImpl implements Lol { @Override pub...

I am trying to catch a specific runtime exception (so not throwable) and just log it (log.error has a void return type). What is the simplest way to do this in vavr? try { sayHello(); } catch (My...

Hello Im trying to add vavr to my projet, right now Im struggling with proper serializaition of Vavr.List objects. Below is my controller: import io.vavr.collection.List; @GetMapping(value = "/x...

I have been working with Java for several years now. Recently came across Vavr, a functional library for Java, that provides immutable collection API. I am curious to know the reason for having an ...

What is the most idiomatic way to transform a Stream<Tuple2<T,U>> into a Map<T,List<U>> with javaslang 2.1.0-alpha? // initial stream Stream.of( Tuple.of("foo", "x"), T...

I am currently looking at Javaslang library and I am trying to convert some of my code to Javaslang. I currently have this bit of code which is all pure Java Cell[][] maze; //from input Map<Ce...

I am using Javaslang-2.1.0-alpha and its Javaslang-match equivalent to do some object decomposition. According to this by blog post by Daniel in the "Match the Fancy way" section: Match(person).of...

I've have a method that takes String as an input and should also return a String. The following ASCII art presents the logical flow: Option<A> optA = finder.findA(input); optA /\ isEmpty...

I need to implement an enum to enum converter in java: Enum_2 > Enum_1 and I'd like to do it in generic way. So I defined an interface: interface LabelAware<T extends Enum> { String getLab...