I have a class that sorts a generic set of objects...

# getting-started

[azeDevs]

I have a class that sorts a generic set of objects by name, and had been using a Function Interface to pass in a Function for getting the generic object's name for sorting. I've been struggling to find the Kotlin equivalent to accomplish the same functionality.

[bbaldino]

could you just use a lambda?

[azeDevs]

I'm not sure how that would look syntactically in Kotlin. This is what I'm trying to convert:

FuzzyFinder find = new FuzzyFinder<Kit>(new FuzzyFinder.LookupEntity<Kit>() {
                @Override
                public Result<Kit> lookup(Kit entity) {
                    return new Result<>(entity, entity.getQuery());
                }
            });

[azeDevs]

or rather:

FuzzyFinder find = new FuzzyFinder<Kit>(entity -> new Result<>(entity, entity.getQuery()));

[Ben]

you could use a typealias

[bbaldino]

not sure i've got it all right, but maybe something like

class Result<T>
abstract class Kit {
    abstract fun getQuery(): Result<Kit>
}

typealias FuzzyFinder = (Kit) -> Result<Kit>

val finder: FuzzyFinder = Kit::getQuery

[azeDevs]

It may have been helpful to include the Functional Interface as well:

@FunctionalInterface public interface LookupEntity<T> { Result<T> lookup(T entity); }

[azeDevs]

The generic is currently passed into FuzzyFinder<T> and then inferred by LookupEntity<T> to return Result<T>

[bbaldino]

so in kotlin that's just seen as "a function which takes a T and returns a Result<T>. you could do typealias FuzzyFinder<T> = (T) -> Result<T>

[bbaldino]

and you can declare an instance val finder: FuzzyFinder<XXX> = YYY where YYY can be any function/function reference that takes a single XXX type and returns Result<XXX>

[azeDevs]

would the typealias live within `FuzzyFinder`'s scope?

[azeDevs]

The 2nd part makes sense

[bbaldino]

don't think you can declare a typealias within a class

[bbaldino]

if that's what you mean

[azeDevs]

yeah, I'm still in the process of releasing my mind from OOP

[Dico]

val list = objects.toMutableList()
list.sortBy { it.query }

[Dico]

I don't know what the point is of your result class. Given your description of what you need, I wrote the code above.

[Dico]

You should not release your mind from OOP at all, as kotlin is very much object oriented. Lambdas are used a lit more than in jva though, and for good reason, as most functions accepting them are inlined.

[azeDevs]

Given the description of what I need, it's for sorting a set of generic objects (https://docs.oracle.com/javase/tutorial/java/generics/types.html), which means there's no guaranteed contract for acquiring any given object's title/name.

[azeDevs]

I've solved my issue though, thanks.