how can I do a sealed class that contains a data c...
# getting-startedb
bjonnh
03/04/2019, 6:54 PMhow can I do a sealed class that contains a data class and a String (that's for a Json file where I can have either of these two)
r
Ruckus
03/04/2019, 7:10 PMYou can't, but you can make a wrapper for
StringRuckus
03/04/2019, 7:14 PM Copy code
sealed class Json<T>(val value: T)
class JsonElem(value: String) : Json<String>(value)
class JsonArray(value: List<Json<*>>) : Json<List<Json<*>>>(value)
class JsonObject(value: Map<String, Json<*>>): Json<Map<String, Json<*>>>(value)b
bjonnh
03/04/2019, 7:17 PMI have to see if Moshi handles that
bjonnh
03/04/2019, 7:17 PMthx
k
kevinmost
03/04/2019, 7:28 PMYou can use custom adapters in Moshi to serialize it however you want
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bjonnh
03/04/2019, 7:34 PMyes that's what I am trying but I have issues wrapping my head around how I'm supposed to get something that can return one of the two types
bjonnh
03/04/2019, 7:50 PM@kevinmost do you have any reference for moshi where polymorphic is applied to a type inside a file?
bjonnh
03/04/2019, 7:50 PMI can only find examples where it is polymorphic on file
k
kevinmost
03/04/2019, 7:51 PMgenerally to make "polymorphic JSON", you'd have some sort of "type" string to go along with the actual data object, and you'd switch on that string to determine what serializer/deserializer logic to use
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bjonnh
03/04/2019, 8:21 PMyeah in that format (that I don't control), I get: [{"query":"foo", "to":"bar"}, "OR", {…}]
k
kevinmost
03/04/2019, 8:23 PMI'm not too familiar with Moshi, honestly, but Gson's TypeAdapterFactory would let you peer into the JSON before you decide what logic to use
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bjonnh
03/04/2019, 8:24 PMI should just switch my JSON lib then
bjonnh
03/04/2019, 8:25 PMit reminds me of all those web framework, they all show you how easy it is to do a todo list, and then they don't tell you that anything more complex will take you days of tweaking…
k
kevinmost
03/04/2019, 8:28 PMyou shouldn't do that. Moshi can do everything Gson can and more. What you're trying to do is not standard with JSON, and thus is clunky to do in any framework. JSON that's polymorphic without a "type" string sitting next to it is just objectively bad API design
kevinmost
03/04/2019, 8:28 PMyou're gonna switch to Gson, implement TypeAdapterFactory, and realize that it's at least as weird via Gson as it is via Moshi
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bjonnh
03/04/2019, 8:29 PMhmm
bjonnh
03/04/2019, 8:30 PMI wanted to handle that field for the sake of completeness, I will probably just ignore it…
s
sitepodmatt
03/05/2019, 1:02 AMdont forget to read the recent changelog, moshi added a polymorphicjsonadapter for event sourcing, not switched yet since I built my _type adapter a while ago
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bjonnh
03/05/2019, 4:20 PMthx. What I'm lacking mostly is really examples on how to use that…
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