Android - Generic type as a Expressions In ObservableTransformer

Question

I will be using observable transformer in my application for converting data from one type to another, so for this use i created a generic class with one parameter <T1> where T1 is the type am expecting to get the output

Example

class Transformer<T1> {

    fun transform(): ObservableTransformer<String, T1> {

        return ObservableTransformer { data ->

            data.map {

                if (T1 is Int) {       //getting compilation error like T1 is not an expression
                    return IntDataType
                }

                if (T1 is Double) { //getting compilation error like T1 is not an expression
                    return DoubleDataType
                }
            }
        }
    }
}

The above class is the transformer which gets the input as string and convert String to someData type based on given generic type T1
So i will be calling the above like this

 getSomeData()
            .compose(Transformer<Double>().tranform())
            .map{ it: double
            }

is there is any other solution to perform like this type of transformer ? Any help

score 2 · Accepted Answer · answered May 08 '19 at 07:11

The T1 is Int non-statement doesn't work, because T1 is a generic type and while is Int checks the type of an object: 1 is Int

You could write a dedicated transformer instead of using generics for it. In general you're loosing the type information of T1 on runtime.

fun Observable<String>.asDouble() = map { it.toDouble() }

getSomeData().asDouble().map { value: Double -> }

You don't even need an actual transformer as it's a simple mapping.

Android - Generic type as a Expressions In ObservableTransformer

1 Answers1