If I have a package and have functions declared in it (not any class besides package itself) - is it...

# getting-started

[Serge]

If I have a package and have functions declared in it (not any class besides package itself) - is it possible by using reflection to obtain list of those declared functions? I have tried to do something like this -

val o = object{}
val mm = o.javaClass.declaredMethods

but it doesn't return anything. is it possible at all? if so, would the function modifier affect this search (private, public, etc)?

[diesieben07]

Not without classpath scanning (quite ugly and unreliable).
The functions could be scattered across many many class files.

[Serge]

@diesieben07 if to assume I have only one *.tk file with package temp.test and few functions in it. how this would look like then? I don't have any class declared

[diesieben07]

You'd have to get one of the functions in there, get it's java.lang.Method and then call getDeclaringClass. However this is a hack and not guaranteed to work in the future.

[Serge]

@diesieben07 neither of these kc or fc would allow to do what you're just saying -

fun main(args: Array<String>) {
  val o = object{}
  val kc = o::class
  val jc = o.javaClass }

unfortunately

[diesieben07]

Well, that is not at all what I said.
Assuming you have foo and bar in com.example package.
Then you can do ::foo.javaMethod!!.declaringClass.declaredMethods.
However that would only list the functions declared in that same .kt file.

[diesieben07]

A cleaner way to do this would be to use kotlin-metadata-jvm (https://github.com/JetBrains/kotlin/tree/master/libraries/kotlinx-metadata/jvm), which can parse the @Metadata annotation and could be used to obtain more kotlin-esque information about the function (not just Java reflection methods)

[Serge]

Thank you @diesieben07 I see... I actually need it for one file, so this approach would work for me and i would do this from within main(), so it works too. Let's say I need find only functions that start with "foo" then I will do this like that (from within main) -

::main.javaMethod!!.declaringClass.declaredMethods.filter { it.name.startsWith("foo") }.map {it-> it.name}

[diesieben07]

Yes, that would work, albeit being very ugly 😛