Retrofit with Kotlin traits that include implemented methods

Question

Traits work well with Retrofit as long as there is no extra method implemented. Depending on return type RetrofitError: TwitchApi.someMethod: HTTP method annotation is required (e.g., @GET, @POST, etc.). or java.lang.IllegalArgumentException: TwitchApi.someMethod: Must have either a return type or Callback as last argument. is thrown.

Is there a way to make retrofit ignore a method that is not annotated with any of retrofit.http.GET / PUT / ... ?

public trait SomeApi {

    GET("/endpoint")
    public fun getSomething(Query("user") user: String): Observable<SomeResponse>

    class object {
        public fun create(): SomeApi {
            val restAdapter = RestAdapter.Builder().setEndpoint("http://localhost").build()
            return restAdapter.create<TwitchApi>(javaClass<SomeApi >())
        }
    }

    public fun someMethodThatBreaksRetrofit(user: String) : Int {
        return processResponse(getSomething(user))
    }
}

`trait` has been renamed to `interface` ... changing that will help other people search and find this question. — Jayson Minard, Jan 02 '16 at 02:32

score 9 · Accepted Answer · edited Jun 27 '16 at 13:19

9

You shouldn't do like that at all. Fortunately in Kotlin you can use extension functions so

interface SomeApi {
    GET("/endpoint")
    fun getSomething(Query("user") user: String): Observable<SomeResponse>
}

fun SomeApi.someMethod(user : String) : Observable<Int>
    = processResponse(getSomething(user))

edited Jun 27 '16 at 13:19

atok

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answered Mar 10 '15 at 09:13

Sergey Mashkov

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I believe it look fine in Kotlin so you don't need another hack. – Sergey Mashkov Mar 10 '15 at 09:33
Thank you :) Kotlin looks better and better :) – atok Mar 10 '15 at 09:34
Just note that as far as your getSomething is async (returns Observable) then someMethod actoually should be async too (should return Observable) – Sergey Mashkov Mar 10 '15 at 09:40
`trait` has been renamed to `interface`, please update this code sample – Jayson Minard Jan 02 '16 at 02:32

Retrofit with Kotlin traits that include implemented methods

1 Answers1