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/*
* Copyright 2017-2018 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
*/
package kotlinx.serialization.json
import kotlinx.serialization.*
/**
* Encoder used by [Json] during serialization.
* This interface can be used to inject desired behaviour into a serialization process of [Json].
*
* Typical example of the usage:
* ```
* // Class representing Either<Left|Right>
* sealed class DummyEither {
* data class Left(val errorMsg: String) : DummyEither()
* data class Right(val data: Payload) : DummyEither()
* }
*
* // Serializer injects custom behaviour by inspecting object content and writing
* object EitherSerializer : KSerializer<DummyEither> {
* override val descriptor: SerialDescriptor = SerialClassDescImpl("DummyEither")
*
* override fun deserialize(decoder: Decoder): DummyEither {
* val input = decoder as? JsonInput ?: throw SerializationException("This class can be loaded only by Json")
* val tree = input.decodeJson() as? JsonObject ?: throw SerializationException("Expected JsonObject")
* if ("error" in tree) return DummyEither.Left(tree.getPrimitive("error").content)
* return DummyEither.Right(input.json.decodeJson(tree, Payload.serializer()))
* }
*
* override fun serialize(encoder: Encoder, obj: DummyEither) {
* val output = encoder as? JsonOutput ?: throw SerializationException("This class can be saved only by Json")
* val tree = when (obj) {
* is DummyEither.Left -> JsonObject(mapOf("error" to JsonLiteral(obj.errorMsg)))
* is DummyEither.Right -> output.json.toJson(obj.data, Payload.serializer())
* }
*
* output.encodeJson(tree)
* }
* }
* ```
*/
public interface JsonOutput: Encoder, CompositeEncoder {
/**
* An instance of the current [Json].
*/
public val json: Json
/**
* Appends given [element] to the output.
*/
public fun encodeJson(element: JsonElement)
}
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