I want to know why I have to pass dataManager(instance of DataManager), I only want that when I call getData() ,then at call time I have to pass function of DataManager that takes only parameter WebDataListener<T>

Because the type of

func

is

DataManager.(Listener) -> Unit

, you have to specify which

DataManager

is used to receive the

.(Listener) -> Unit

function call

ok I got it

I don't quite get what you mean, could you explain a bit?

i only want to call HighOreder (func) inside getData() function, but when i calling getData() then i am asked to call func like getData(otherParams){ BaseDataDelegation(this,listener)// i don't want to call it here}

The point of higher order function is that the caller don't need to know the function impl, the impl is provided by the caller

but can i use method refrence here like DataManger::functionName , actully i have used this and its working , i want your advice

That's the correct way I think

yea its working correctly but i don't have any Refrence of it so therefore i'm doubting this and not sure about it