I need to pass an arbitrary number of objects to m...

# getting-started

[Marcin Wisniowski]

I need to pass an arbitrary number of objects to my method (so I could use a List argument, or a vararg), but the class I am passing has a generic type, and the type could be different for each one of them, so I can’t use a list or vararg. Is there any better way of achieving this than fun <T1, T2, T3, T4, T5> method(arg1: Arg<T1>, arg2: Arg<T2>, arg3: Arg<T3>, arg4: Arg<T4>, arg5: Arg<T5>)?

[Adam S]

There might be ways of making it a little more ergonomic, but the direct answer to your question is ‘no’.

It might help to create a specific type with the generic types

class MethodParams<T1, T2, T3...>(
  val arg1: Arg<T1>, 
  val arg2: Arg<T2>, 
  val arg3: Arg<T3>, 
  ...
) {
  fun method(...)
}

but that just moves the problem around.

If you have control over the types then you could add an interface that could describe how the types are used within a method. This works well with sealed types.

For example, if all of the types are some sort of data type then you could create

sealed interface MyDataType

value class MyIntType(val value: Int) : MyDataType
value class MyStringType(val value: String) : MyDataType

and then the function could be simplified to only accept MyDataType

fun method(
  arg1: MyDataType,
  arg2: MyDataType,
  arg3: MyDataType,
)

[Joffrey]

If the types are arbitrary, why not just use a list or vararg with a wildcard?

fun yourFunction(args: List<TheType<*>>) { 
... }