Converting a HashMap using moshi

Question

I'm trying to convert a HashMap of elements into a JSON string. I'm using the method used in this link.

 val elementsNew: HashMap<String, Element> = HashMap(elements)
 val type = Types.newParameterizedType(Map::class.java, String::class.java, Element::class.java)
 var json: String = builder.adapter(type).toJson(elementsNew)

But this gives the following error

Error:(236, 40) Type inference failed: Not enough information to infer parameter T in fun adapter(p0: Type!): JsonAdapter! Please specify it explicitly.

Can any one tell me where's the fault? Is it because of Kotlin?

worth noting that it's not exactly because of Kotlin. In Java, you'd end up with `JsonAdapter — Eric Cochran, Dec 15 '17 at 22:09

score 11 · Accepted Answer · answered Dec 15 '17 at 11:37

11

Looking at the signature of the adapter() method, it can't infer its type parameter from the argument:

public <T> JsonAdapter<T> adapter(Type type)

Hence you have to provide the type explicitly:

var json = builder.adapter<Map<String, Element>>(type).toJson(elementsNew)

or alternatively:

val adapter: JsonAdapter<Map<String, Element>> = builder.adapter(type)
var json = adapter.toJson(elementsNew)

answered Dec 15 '17 at 11:37

Egor

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This did work. I thought since the link didn't have templates, it won't need them. – Sanka Darshana Dec 15 '17 at 12:46
1

I like the first one, declaring the type parameters explicitly and keeping the implicit declaration type. also, less code. – Eric Cochran Dec 15 '17 at 22:05

Converting a HashMap using moshi

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