How to convert EnumSet<A> to Set<B> - kotlin

Question

I have an enum class thats something like this:
enum class SomeType(val id: String) {
TYPE1("A"),
TYPE2("B"),
TYPE3("C"),
TYPE4("D")
}
Now, I need to filter a list of Something which has a String that's stated in SomeType enum. So Basically I have something like this:
class Something(val id: String)
// where the value of id is one of the value of the SomeType's id
I have a list of Something like so:
val somethingList = arrayListOf<Something>(
Something("A"),
Something("B"),
Something("A"),
Something("C"),
Something("D"),
Something("A"),
Something("D")
)
Now I need to filter that somethingList to by the given EnumSet<SomeType>.
So if I have a:
val someTypeSet = EnumSet.of(SomeType.Type3, SomeType.Type2)
the resulting filtered List should be,
val filteredList = arrayListOf<Something>(
Something("B"),
Something("C")
)
My idea is to convert the someTypeSet to a Set<String> and just do something like:
Set<String> setOfSomeTypeIds = convertToSet(someTypeSet)
val filteredList = somethingList.filter { something ->
setOfSomeTypeIds.contains(something.id)
}
Can someone guide me how to convert an EnumSet to a Set of its value?
I also explained the whole process just in case there is a better solution to the problem above.
Anything will be appreciated.
Thanks in advance.

Answer 1

You can use map on any collection to transform it to a new collection with the desired values... i.e. someTypeSet.map { it.id } will already return you a list of string. If you really want to have a Set you can also use something like mapTo. Regarding the filter that might also be simplifiable using the in-keyword, e.g.: somethingList.filter { it.id in setOfSomeTypeIds }.
So summarized:
val setOfSomeTypeIds = someTypeSet.map { it.id }
val filteredList = somethingList.filter { it.id in setOfSomeTypeIds }

Answer 2

You can use the map function after you filter the relevant types.
val filteredSomethings:List<Something> = someTypeSet.filter { something ->
setOfSomeTypeIds.contains(something.id) }.map { Something(it.id) }
It will return a List of Something with the relevant Ids.