How could I get the enum value using Android WorkManager s D

Question

How could I get the enum value using Android WorkManager s Data getString s value ``` ExperimentalStdlibApi inline fun lt reified T gt Data getValue obj Any prop KProperty lt gt T return when T class String class gt getString prop name as T Int class gt getInt prop name 1 as T Boolean class gt getBoolean prop name false as T Enum class gt getString prop name let enumValueOf lt T gt it This doesn t compile else gt error Trying to retrieve invalid type in Data for $ prop name $ T class ```

dave08 · Answer

The goal is to have something like ```enum Foo BAZ BAR class SomeData val inputData Data val dataEnumKeyForFoo Foo by inputData Saved as a string in Data with the key `dataEnumKeyForFoo` and the value one of the enum value s names ```

Javier · Answer

`obj` is used for something

Joffrey · Answer

I don t believe you can get type inference from this kind of `when` on the class of `T` even with a reified `T` This is why you needed to cast in the other cases I think you could use delegate providers instead of direct delegates And for instance provide one for primitives and one for enums with extra constraint on `T Enum lt T gt ` which will allow `enumValueOf` ```class SomeData val inputData Data val dataEnumKeyForFoo Foo by inputData enum val otherProp Int by inputData primitive ``` But you could even go as far as creating one for each primitive type too

Joffrey · Answer

< Javier> I think that `obj` is necessary to conform to the delegate contract even if not used

Javier · Answer

but what is the type

Joffrey · Answer

The type of what

Javier · Answer

because you maybe can ```when obj is String gt as T is Enum lt gt gt as T else gt as T ```

Joffrey · Answer

I think `obj` is the instance of the class in which the property is declared so it s not of type `T` In the given example `obj` would be of type `SomeData`

dave08 · Answer

`obj` isn t needed since such a class just contains a Data instance the truth is if I make that `obj` a `DataProvider` then I wouldn t need the receiver to be `Data` I could retrieve it from `obj` but I don t think that would help too much

dave08 · Answer

So `enum ` would return a `ReadWriteProperty` implementation

dave08 · Answer

I guess I can t avoid creating one instance per property per class

dave08 · Answer

I can t use enumValueOf with since it s not reified ```class EnumDataProperty lt T Enum lt T gt gt ReadWriteProperty lt Data T gt override fun getValue thisRef Data property KProperty lt gt T return thisRef getString property name let enumValueOf it override fun setValue thisRef Data property KProperty lt gt value T TODO Not yet implemented ```

dave08 · Answer

I guess not everything is so simple with delegate properties set wouldn t work because it s a Data Builder I ended up with ```inline fun lt reified T Enum lt T gt gt Data getEnum key String T = getString key let enumValueOf lt T gt it inline fun lt reified T Enum lt T gt gt Data Builder putEnum key String value T Data Builder putString key value name return this inline fun buildData configure Data Builder gt Data Builder Data = Data Builder apply configure build ```