some elegant solution for allocating a not-nullabl...

# announcements

[elect]

some elegant solution for allocating a not-nullable array as buffer for a generic ringBuffer implementation since I cant use inline reified?
The only option I see is to pass down as argument the class itself

[diesieben07]

Why can't you use inline + reified exactly?

[elect]

class SteamVR_RingBuffer<T>(clazz: Class<T>, size: Int) {

    protected val buffer = Array(size) {
        clazz.getDeclaredConstructor().newInstance() }

[elect]

only functions can be reified

[diesieben07]

You can extend that class as follows:

companion object {
  inline operator fun <reified T : Any> invoke() = SteamVR_RingBuffer(T::class)
}

[elect]

uh nice

[diesieben07]

Then you can use both the reified "fake constructor" or the normal one

[elect]

thanks man

[elect]

another thing @diesieben07

[elect]

compiler complains about T here

class SteamVR_RingBuffer<T : Any>(val clazz: Class<T>, size: Int) {

    val default: T
        get() = clazz.getDeclaredConstructor().newInstance()

    protected val buffer = Array(size) { default }

[elect]

cant use T as reified parameter, use a class instead

[elect]

but it doesnt look it accepts clazz either

[diesieben07]

Yeah, you probably shouldn't use Array<T>.
Arrays are weird on the JVM in that Array<String> and Array<Any> are completely different classes (every element type has it's own class)

[diesieben07]

You should probably use Array<Any> and insert appropriate casts at the appropriate places.

[diesieben07]

That is what things like ArrayList do inside, too.

[elect]

uhm, ok

[cbruegg]

Or just use a list as the buffer?

[elect]

arrays shall be better for performances

[cbruegg]

Sidenote: The standard naming convention would be SteamVRRingBuffer

[elect]

I know, but it's a port

[cbruegg]

Did you measure whether it actually gives a performance advantage? An ArrayList is, as the name implies, backed by an array and should give similar performance.

[elect]

no, I always read about it around

[cbruegg]

The JVM is also pretty good at inlining methods in hot code

[cbruegg]

I'd just use a list and only if that hurts performance use a raw array