[kotlin][client] add support for unknown default case with Kotlinx Serialization (#12930)

* [kotlin][client] Kotlinx Serialization cleanup

* [kotlin][client] Kotlinx Serialization cleanup

* [kotlin][client] add support for unknown default case with Kotlinx Serialization

* [kotlin][client] add support for unknown default case with Kotlinx Serialization

* [kotlin][client] add support for unknown default case with Kotlinx Serialization

* [kotlin][client] improve Kotlinx Serialization naming

* [kotlin][client] improve Kotlinx Serialization naming

bin/configs/kotlin-json-request-string.yaml

@@ -7,3 +7,5 @@ additionalProperties:
   artifactId: kotlin-petstore-json-request-string
   parcelizeModels: true
   supportAndroidApiLevel25AndBelow: true
+  serializationLibrary: kotlinx_serialization
+  enumUnknownDefaultCase: "true"

bin/configs/kotlin-uppercase-enum.yaml

@@ -5,3 +5,5 @@ templateDir: modules/openapi-generator/src/main/resources/kotlin-client
 additionalProperties:
   artifactId: kotlin-uppercase-enum
   enumPropertyNaming: UPPERCASE
+  serializationLibrary: kotlinx_serialization
+  enumUnknownDefaultCase: "true"

modules/openapi-generator/src/main/resources/kotlin-client/data_class.mustache

@@ -19,6 +19,13 @@ import com.fasterxml.jackson.annotation.JsonTypeInfo
 import {{#serializableModel}}kotlinx.serialization.Serializable as KSerializable{{/serializableModel}}{{^serializableModel}}kotlinx.serialization.Serializable{{/serializableModel}}
 import kotlinx.serialization.SerialName
 import kotlinx.serialization.Contextual
+{{#enumUnknownDefaultCase}}
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.builtins.serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+{{/enumUnknownDefaultCase}}
 {{#hasEnums}}
 {{/hasEnums}}
 {{/kotlinx_serialization}}
@@ -88,7 +95,7 @@ import {{packageName}}.infrastructure.ITransformForStorage
      */
     {{^multiplatform}}
     {{#kotlinx_serialization}}
-    {{#serializableModel}}@KSerializable{{/serializableModel}}{{^serializableModel}}@Serializable{{/serializableModel}}
+    {{#serializableModel}}@KSerializable{{/serializableModel}}{{^serializableModel}}@Serializable{{#enumUnknownDefaultCase}}(with = {{classname}}Serializer::class){{/enumUnknownDefaultCase}}{{/serializableModel}}
     {{/kotlinx_serialization}}
     {{/multiplatform}}
     {{#multiplatform}}
@@ -116,7 +123,22 @@ import {{packageName}}.infrastructure.ITransformForStorage
         {{/multiplatform}}
     {{/enumVars}}
     {{/allowableValues}}
+    }{{#kotlinx_serialization}}{{#enumUnknownDefaultCase}}
+
+    @Serializer(forClass = {{{nameInCamelCase}}}::class)
+    internal object {{nameInCamelCase}}Serializer : KSerializer<{{nameInCamelCase}}> {
+        override val descriptor = {{{dataType}}}.serializer().descriptor
+
+        override fun deserialize(decoder: Decoder): {{nameInCamelCase}} {
+            val value = decoder.decodeSerializableValue({{{dataType}}}.serializer())
+            return {{nameInCamelCase}}.values().firstOrNull { it.value == value }
+                ?: {{nameInCamelCase}}.{{#allowableValues}}{{#enumVars}}{{#-last}}{{&name}}{{/-last}}{{/enumVars}}{{/allowableValues}}
         }
+
+        override fun serialize(encoder: Encoder, value: {{nameInCamelCase}}) {
+            encoder.encodeSerializableValue({{{dataType}}}.serializer(), value.value)
+        }
+    }{{/enumUnknownDefaultCase}}{{/kotlinx_serialization}}
 {{/isEnum}}
 {{/vars}}
 {{/hasEnums}}

modules/openapi-generator/src/main/resources/kotlin-client/enum_class.mustache

@@ -11,6 +11,13 @@ import com.fasterxml.jackson.annotation.JsonProperty
 {{#kotlinx_serialization}}
 import kotlinx.serialization.SerialName
 import kotlinx.serialization.Serializable
+{{#enumUnknownDefaultCase}}
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.builtins.serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+{{/enumUnknownDefaultCase}}
 {{/kotlinx_serialization}}
 {{/multiplatform}}
 {{#multiplatform}}
@@ -22,7 +29,7 @@ import kotlinx.serialization.*
  *
  * Values: {{#allowableValues}}{{#enumVars}}{{&name}}{{^-last}},{{/-last}}{{/enumVars}}{{/allowableValues}}
  */
-{{#multiplatform}}@Serializable{{/multiplatform}}{{#kotlinx_serialization}}@Serializable{{/kotlinx_serialization}}
+{{#multiplatform}}@Serializable{{/multiplatform}}{{#kotlinx_serialization}}@Serializable{{#enumUnknownDefaultCase}}(with = {{classname}}Serializer::class){{/enumUnknownDefaultCase}}{{/kotlinx_serialization}}
 {{#nonPublicApi}}internal {{/nonPublicApi}}enum class {{classname}}(val value: {{{dataType}}}) {
 {{#allowableValues}}{{#enumVars}}
     {{^multiplatform}}
@@ -79,4 +86,19 @@ import kotlinx.serialization.*
           }
         }
     }
-}
+}{{#kotlinx_serialization}}{{#enumUnknownDefaultCase}}
+
+@Serializer(forClass = {{classname}}::class)
+internal object {{classname}}Serializer : KSerializer<{{classname}}> {
+    override val descriptor = {{{dataType}}}.serializer().descriptor
+
+    override fun deserialize(decoder: Decoder): {{classname}} {
+        val value = decoder.decodeSerializableValue({{{dataType}}}.serializer())
+        return {{classname}}.values().firstOrNull { it.value == value }
+            ?: {{classname}}.{{#allowableValues}}{{#enumVars}}{{#-last}}{{&name}}{{/-last}}{{/enumVars}}{{/allowableValues}}
+    }
+
+    override fun serialize(encoder: Encoder, value: {{classname}}) {
+        encoder.encodeSerializableValue({{{dataType}}}.serializer(), value.value)
+    }
+}{{/enumUnknownDefaultCase}}{{/kotlinx_serialization}}

modules/openapi-generator/src/main/resources/kotlin-client/jvm-common/infrastructure/LocalDateAdapter.kt.mustache

@@ -72,7 +72,7 @@ import org.threeten.bp.format.DateTimeFormatter
 {{/gson}}
 {{#kotlinx_serialization}}
 @Serializer(forClass = LocalDate::class)
-object LocalDateAdapter : KSerializer<LocalDate> {
+{{#nonPublicApi}}internal {{/nonPublicApi}}object LocalDateAdapter : KSerializer<LocalDate> {
     override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("LocalDate", PrimitiveKind.STRING)
 
     override fun serialize(encoder: Encoder, value: LocalDate) {

modules/openapi-generator/src/main/resources/kotlin-client/jvm-common/infrastructure/LocalDateTimeAdapter.kt.mustache

@@ -72,7 +72,7 @@ import org.threeten.bp.format.DateTimeFormatter
 {{/gson}}
 {{#kotlinx_serialization}}
 @Serializer(forClass = LocalDateTime::class)
-object LocalDateTimeAdapter : KSerializer<LocalDateTime> {
+{{#nonPublicApi}}internal {{/nonPublicApi}}object LocalDateTimeAdapter : KSerializer<LocalDateTime> {
     override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("LocalDateTime", PrimitiveKind.STRING)
 
     override fun serialize(encoder: Encoder, value: LocalDateTime) {

modules/openapi-generator/src/main/resources/kotlin-client/jvm-common/infrastructure/OffsetDateTimeAdapter.kt.mustache

@@ -72,7 +72,7 @@ import org.threeten.bp.format.DateTimeFormatter
 {{/gson}}
 {{#kotlinx_serialization}}
 @Serializer(forClass = OffsetDateTime::class)
-object OffsetDateTimeAdapter : KSerializer<OffsetDateTime> {
+{{#nonPublicApi}}internal {{/nonPublicApi}}object OffsetDateTimeAdapter : KSerializer<OffsetDateTime> {
     override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("OffsetDateTime", PrimitiveKind.STRING)
 
     override fun serialize(encoder: Encoder, value: OffsetDateTime) {

modules/openapi-generator/src/main/resources/kotlin-client/jvm-common/infrastructure/Serializer.kt.mustache

@@ -98,8 +98,13 @@ import java.util.concurrent.atomic.AtomicLong
         .configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false)
 {{/jackson}}
 {{#kotlinx_serialization}}
+    @Deprecated("Use Serializer.kotlinxSerializationAdapters instead", replaceWith = ReplaceWith("Serializer.kotlinxSerializationAdapters"))
     @JvmStatic
-    val kotlinSerializationAdapters = SerializersModule {
+    val kotlinSerializationAdapters: SerializersModule
+        get() { return kotlinxSerializationAdapters }
+
+    @JvmStatic
+    val kotlinxSerializationAdapters = SerializersModule {
         contextual(BigDecimal::class, BigDecimalAdapter)
         contextual(BigInteger::class, BigIntegerAdapter)
         contextual(LocalDate::class, LocalDateAdapter)
@@ -114,7 +119,18 @@ import java.util.concurrent.atomic.AtomicLong
         contextual(StringBuilder::class, StringBuilderAdapter)
     }
 
+    @Deprecated("Use Serializer.kotlinxSerializationJson instead", replaceWith = ReplaceWith("Serializer.kotlinxSerializationJson"))
     @JvmStatic
-    val jvmJson: Json by lazy { Json { serializersModule = kotlinSerializationAdapters } }
+    val jvmJson: Json
+        get() { return kotlinxSerializationJson }
+
+    @JvmStatic
+    val kotlinxSerializationJson: Json by lazy {
+        Json {
+            serializersModule = kotlinxSerializationAdapters
+            ignoreUnknownKeys = true
+            isLenient = true
+        }
+    }
 {{/kotlinx_serialization}}
 }

modules/openapi-generator/src/main/resources/kotlin-client/jvm-common/infrastructure/URIAdapter.kt.mustache

@@ -26,7 +26,7 @@ import java.net.URI
 {{/moshi}}
 {{#kotlinx_serialization}}
 @Serializer(forClass = URI::class)
-object URIAdapter : KSerializer<URI> {
+{{#nonPublicApi}}internal {{/nonPublicApi}}object URIAdapter : KSerializer<URI> {
     override fun serialize(encoder: Encoder, value: URI) {
         encoder.encodeString(value.toASCIIString())
     }

modules/openapi-generator/src/main/resources/kotlin-client/jvm-common/infrastructure/UUIDAdapter.kt.mustache

@@ -26,7 +26,7 @@ import java.util.UUID
 {{/moshi}}
 {{#kotlinx_serialization}}
 @Serializer(forClass = UUID::class)
-object UUIDAdapter : KSerializer<UUID> {
+{{#nonPublicApi}}internal {{/nonPublicApi}}object UUIDAdapter : KSerializer<UUID> {
     override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("UUID", PrimitiveKind.STRING)
 
     override fun serialize(encoder: Encoder, value: UUID) {

modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-okhttp/infrastructure/ApiClient.kt.mustache

@@ -169,7 +169,7 @@ import com.squareup.moshi.adapter
                         MediaType.parse(mediaType ?: JsonMediaType), Serializer.jacksonObjectMapper.writeValueAsString(content)
                         {{/jackson}}
                         {{#kotlinx_serialization}}
-                        MediaType.parse(mediaType ?: JsonMediaType), Serializer.jvmJson.encodeToString(content)
+                        MediaType.parse(mediaType ?: JsonMediaType), Serializer.kotlinxSerializationJson.encodeToString(content)
                         {{/kotlinx_serialization}}
                     )
                 }
@@ -188,7 +188,7 @@ import com.squareup.moshi.adapter
                     Serializer.jacksonObjectMapper.writeValueAsString(content)
                     {{/jackson}}
                     {{#kotlinx_serialization}}
-                    Serializer.jvmJson.encodeToString(content)
+                    Serializer.kotlinxSerializationJson.encodeToString(content)
                     {{/kotlinx_serialization}}
                         .toRequestBody((mediaType ?: JsonMediaType).toMediaTypeOrNull())
                 }
@@ -236,7 +236,7 @@ import com.squareup.moshi.adapter
                 {{#moshi}}Serializer.moshi.adapter<T>().fromJson(bodyContent){{/moshi}}{{!
                 }}{{#gson}}Serializer.gson.fromJson(bodyContent, (object: TypeToken<T>(){}).getType()){{/gson}}{{!
                 }}{{#jackson}}Serializer.jacksonObjectMapper.readValue(bodyContent, object: TypeReference<T>() {}){{/jackson}}{{!
-                }}{{#kotlinx_serialization}}Serializer.jvmJson.decodeFromString<T>(bodyContent){{/kotlinx_serialization}}
+                }}{{#kotlinx_serialization}}Serializer.kotlinxSerializationJson.decodeFromString<T>(bodyContent){{/kotlinx_serialization}}
             else ->  throw UnsupportedOperationException("responseBody currently only supports JSON body.")
         }
     }
@@ -432,7 +432,7 @@ import com.squareup.moshi.adapter
         return Serializer.jacksonObjectMapper.writeValueAsString(value).replace("\"", "")
         {{/jackson}}
         {{#kotlinx_serialization}}
-        return Serializer.jvmJson.encodeToString(value).replace("\"", "")
+        return Serializer.kotlinxSerializationJson.encodeToString(value).replace("\"", "")
         {{/kotlinx_serialization}}
         {{/toJson}}
         {{^toJson}}

modules/openapi-generator/src/main/resources/kotlin-client/libraries/jvm-retrofit2/infrastructure/ApiClient.kt.mustache

@@ -51,7 +51,7 @@ import retrofit2.converter.moshi.MoshiConverterFactory
 
 {{#kotlinx_serialization}}
 import com.jakewharton.retrofit2.converter.kotlinx.serialization.asConverterFactory
-import {{packageName}}.infrastructure.Serializer.jvmJson
+import {{packageName}}.infrastructure.Serializer.kotlinxSerializationJson
 import okhttp3.MediaType.Companion.toMediaType
 {{/kotlinx_serialization}}
 
@@ -84,7 +84,7 @@ import okhttp3.MediaType.Companion.toMediaType
             .addConverterFactory(MoshiConverterFactory.create(serializerBuilder.build()))
             {{/moshi}}
             {{#kotlinx_serialization}}
-            .addConverterFactory(jvmJson.asConverterFactory("application/json".toMediaType()))
+            .addConverterFactory(kotlinxSerializationJson.asConverterFactory("application/json".toMediaType()))
             {{/kotlinx_serialization}}
             .apply {
                 if (converterFactory != null) {

samples/client/petstore/kotlin-json-request-string/.openapi-generator/FILES

@@ -13,6 +13,7 @@ gradle/wrapper/gradle-wrapper.jar
 gradle/wrapper/gradle-wrapper.properties
 gradlew
 gradlew.bat
+proguard-rules.pro
 settings.gradle
 src/main/kotlin/org/openapitools/client/apis/PetApi.kt
 src/main/kotlin/org/openapitools/client/apis/StoreApi.kt
@@ -20,9 +21,11 @@ src/main/kotlin/org/openapitools/client/apis/UserApi.kt
 src/main/kotlin/org/openapitools/client/infrastructure/ApiAbstractions.kt
 src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
 src/main/kotlin/org/openapitools/client/infrastructure/ApiResponse.kt
+src/main/kotlin/org/openapitools/client/infrastructure/AtomicBooleanAdapter.kt
+src/main/kotlin/org/openapitools/client/infrastructure/AtomicIntegerAdapter.kt
+src/main/kotlin/org/openapitools/client/infrastructure/AtomicLongAdapter.kt
 src/main/kotlin/org/openapitools/client/infrastructure/BigDecimalAdapter.kt
 src/main/kotlin/org/openapitools/client/infrastructure/BigIntegerAdapter.kt
-src/main/kotlin/org/openapitools/client/infrastructure/ByteArrayAdapter.kt
 src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
 src/main/kotlin/org/openapitools/client/infrastructure/LocalDateAdapter.kt
 src/main/kotlin/org/openapitools/client/infrastructure/LocalDateTimeAdapter.kt
@@ -32,7 +35,9 @@ src/main/kotlin/org/openapitools/client/infrastructure/RequestConfig.kt
 src/main/kotlin/org/openapitools/client/infrastructure/RequestMethod.kt
 src/main/kotlin/org/openapitools/client/infrastructure/ResponseExtensions.kt
 src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
+src/main/kotlin/org/openapitools/client/infrastructure/StringBuilderAdapter.kt
 src/main/kotlin/org/openapitools/client/infrastructure/URIAdapter.kt
+src/main/kotlin/org/openapitools/client/infrastructure/URLAdapter.kt
 src/main/kotlin/org/openapitools/client/infrastructure/UUIDAdapter.kt
 src/main/kotlin/org/openapitools/client/models/Category.kt
 src/main/kotlin/org/openapitools/client/models/ModelApiResponse.kt

samples/client/petstore/kotlin-json-request-string/build.gradle

@@ -14,11 +14,13 @@ buildscript {
     }
     dependencies {
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+        classpath "org.jetbrains.kotlin:kotlin-serialization:$kotlin_version"
     }
 }
 
 apply plugin: 'kotlin'
 apply plugin: 'kotlin-parcelize'
+apply plugin: 'kotlinx-serialization'
 
 repositories {
     maven { url "https://repo1.maven.org/maven2" }
@@ -30,9 +32,13 @@ test {
 
 dependencies {
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
-    implementation "org.jetbrains.kotlin:kotlin-reflect:$kotlin_version"
+    implementation "org.jetbrains.kotlinx:kotlinx-serialization-json:1.2.1"
-    implementation "com.squareup.moshi:moshi-kotlin:1.12.0"
-    implementation "com.squareup.moshi:moshi-adapters:1.12.0"
     implementation "com.squareup.okhttp3:okhttp:4.9.1"
     testImplementation "io.kotlintest:kotlintest-runner-junit5:3.4.2"
 }
+
+tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).configureEach {
+    kotlinOptions {
+        freeCompilerArgs += "-Xopt-in=kotlinx.serialization.ExperimentalSerializationApi"
+    }
+}

samples/client/petstore/kotlin-json-request-string/proguard-rules.pro

@@ -0,0 +1,11 @@
+-keepattributes *Annotation*, InnerClasses
+-dontnote kotlinx.serialization.AnnotationsKt # core serialization annotations
+
+# kotlinx-serialization-json specific. Add this if you have java.lang.NoClassDefFoundError kotlinx.serialization.json.JsonObjectSerializer
+-keepclassmembers class kotlinx.serialization.json.** { *** Companion; }
+-keepclasseswithmembers class kotlinx.serialization.json.** { kotlinx.serialization.KSerializer serializer(...); }
+
+# project specific.
+-keep,includedescriptorclasses class org.openapitools.client.models.**$$serializer { *; }
+-keepclassmembers class org.openapitools.client.models.** { *** Companion; }
+-keepclasseswithmembers class org.openapitools.client.models.** { kotlinx.serialization.KSerializer serializer(...); }

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/apis/PetApi.kt

@@ -26,7 +26,8 @@ import okhttp3.OkHttpClient
 import org.openapitools.client.models.ModelApiResponse
 import org.openapitools.client.models.Pet
 
-import com.squareup.moshi.Json
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
 
 import org.openapitools.client.infrastructure.ApiClient
 import org.openapitools.client.infrastructure.ApiResponse

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/apis/StoreApi.kt

@@ -25,7 +25,8 @@ import okhttp3.OkHttpClient
 
 import org.openapitools.client.models.Order
 
-import com.squareup.moshi.Json
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
 
 import org.openapitools.client.infrastructure.ApiClient
 import org.openapitools.client.infrastructure.ApiResponse

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/apis/UserApi.kt

@@ -25,7 +25,8 @@ import okhttp3.OkHttpClient
 
 import org.openapitools.client.models.User
 
-import com.squareup.moshi.Json
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
 
 import org.openapitools.client.infrastructure.ApiClient
 import org.openapitools.client.infrastructure.ApiResponse

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -28,7 +28,8 @@ import java.time.LocalTime
 import java.time.OffsetDateTime
 import java.time.OffsetTime
 import java.util.Locale
-import com.squareup.moshi.adapter
+import kotlinx.serialization.decodeFromString
+import kotlinx.serialization.encodeToString
 
 open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClient) {
     companion object {
@@ -105,7 +106,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
                 if (content == null) {
                     EMPTY_REQUEST
                 } else {
-                    Serializer.moshi.adapter(T::class.java).toJson(content)
+                    Serializer.kotlinxSerializationJson.encodeToString(content)
                         .toRequestBody((mediaType ?: JsonMediaType).toMediaTypeOrNull())
                 }
             mediaType == XmlMediaType -> throw UnsupportedOperationException("xml not currently supported.")
@@ -113,7 +114,6 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             else -> throw UnsupportedOperationException("requestBody currently only supports JSON body and File body.")
         }
 
-    @OptIn(ExperimentalStdlibApi::class)
     protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
         if(body == null) {
             return null
@@ -140,7 +140,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
         }
         return when {
             mediaType==null || (mediaType.startsWith("application/") && mediaType.endsWith("json")) ->
-                Serializer.moshi.adapter<T>().fromJson(bodyContent)
+                Serializer.kotlinxSerializationJson.decodeFromString<T>(bodyContent)
             else ->  throw UnsupportedOperationException("responseBody currently only supports JSON body.")
         }
     }

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/AtomicBooleanAdapter.kt

@@ -0,0 +1,21 @@
+package org.openapitools.client.infrastructure
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
+import java.util.concurrent.atomic.AtomicBoolean
+
+@Serializer(forClass = AtomicBoolean::class)
+object AtomicBooleanAdapter : KSerializer<AtomicBoolean> {
+    override fun serialize(encoder: Encoder, value: AtomicBoolean) {
+        encoder.encodeBoolean(value.get())
+    }
+
+    override fun deserialize(decoder: Decoder): AtomicBoolean = AtomicBoolean(decoder.decodeBoolean())
+
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("AtomicBoolean", PrimitiveKind.BOOLEAN)
+}

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/AtomicIntegerAdapter.kt

@@ -0,0 +1,21 @@
+package org.openapitools.client.infrastructure
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
+import java.util.concurrent.atomic.AtomicInteger
+
+@Serializer(forClass = AtomicInteger::class)
+object AtomicIntegerAdapter : KSerializer<AtomicInteger> {
+    override fun serialize(encoder: Encoder, value: AtomicInteger) {
+        encoder.encodeInt(value.get())
+    }
+
+    override fun deserialize(decoder: Decoder): AtomicInteger = AtomicInteger(decoder.decodeInt())
+
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("AtomicInteger", PrimitiveKind.INT)
+}

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/AtomicLongAdapter.kt

@@ -0,0 +1,21 @@
+package org.openapitools.client.infrastructure
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
+import java.util.concurrent.atomic.AtomicLong
+
+@Serializer(forClass = AtomicLong::class)
+object AtomicLongAdapter : KSerializer<AtomicLong> {
+    override fun serialize(encoder: Encoder, value: AtomicLong) {
+        encoder.encodeLong(value.get())
+    }
+
+    override fun deserialize(decoder: Decoder): AtomicLong = AtomicLong(decoder.decodeLong())
+
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("AtomicLong", PrimitiveKind.LONG)
+}

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/BigDecimalAdapter.kt

@@ -1,17 +1,17 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.FromJson
+import kotlinx.serialization.KSerializer
-import com.squareup.moshi.ToJson
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
 import java.math.BigDecimal
 
-class BigDecimalAdapter {
+@Serializer(forClass = BigDecimal::class)
-    @ToJson
+object BigDecimalAdapter : KSerializer<BigDecimal> {
-    fun toJson(value: BigDecimal): String {
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("BigDecimal", PrimitiveKind.STRING)
-        return value.toPlainString()
+    override fun deserialize(decoder: Decoder): BigDecimal = BigDecimal(decoder.decodeString())
-    }
+    override fun serialize(encoder: Encoder, value: BigDecimal) = encoder.encodeString(value.toPlainString())
-
-    @FromJson
-    fun fromJson(value: String): BigDecimal {
-        return BigDecimal(value)
-    }
 }

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/BigIntegerAdapter.kt

@@ -1,17 +1,22 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.FromJson
+import kotlinx.serialization.KSerializer
-import com.squareup.moshi.ToJson
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
 import java.math.BigInteger
 
-class BigIntegerAdapter {
+@Serializer(forClass = BigInteger::class)
-    @ToJson
+object BigIntegerAdapter : KSerializer<BigInteger> {
-    fun toJson(value: BigInteger): String {
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("BigInteger", PrimitiveKind.STRING)
-        return value.toString()
+    override fun deserialize(decoder: Decoder): BigInteger {
+        return BigInteger(decoder.decodeString())
     }
 
-    @FromJson
+    override fun serialize(encoder: Encoder, value: BigInteger) {
-    fun fromJson(value: String): BigInteger {
+        encoder.encodeString(value.toString())
-        return BigInteger(value)
     }
 }

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/ByteArrayAdapter.kt

@@ -1,12 +0,0 @@
-package org.openapitools.client.infrastructure
-
-import com.squareup.moshi.FromJson
-import com.squareup.moshi.ToJson
-
-class ByteArrayAdapter {
-    @ToJson
-    fun toJson(data: ByteArray): String = String(data)
-
-    @FromJson
-    fun fromJson(data: String): ByteArray = data.toByteArray()
-}

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/LocalDateAdapter.kt

@@ -1,19 +1,24 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.FromJson
+import kotlinx.serialization.KSerializer
-import com.squareup.moshi.ToJson
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
 import java.time.LocalDate
 import java.time.format.DateTimeFormatter
 
-class LocalDateAdapter {
+@Serializer(forClass = LocalDate::class)
-    @ToJson
+object LocalDateAdapter : KSerializer<LocalDate> {
-    fun toJson(value: LocalDate): String {
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("LocalDate", PrimitiveKind.STRING)
-        return DateTimeFormatter.ISO_LOCAL_DATE.format(value)
+
+    override fun serialize(encoder: Encoder, value: LocalDate) {
+        encoder.encodeString(DateTimeFormatter.ISO_LOCAL_DATE.format(value))
     }
 
-    @FromJson
+    override fun deserialize(decoder: Decoder): LocalDate {
-    fun fromJson(value: String): LocalDate {
+        return LocalDate.parse(decoder.decodeString(), DateTimeFormatter.ISO_LOCAL_DATE)
-        return LocalDate.parse(value, DateTimeFormatter.ISO_LOCAL_DATE)
     }
-
 }

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/LocalDateTimeAdapter.kt

@@ -1,19 +1,24 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.FromJson
+import kotlinx.serialization.KSerializer
-import com.squareup.moshi.ToJson
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
 import java.time.LocalDateTime
 import java.time.format.DateTimeFormatter
 
-class LocalDateTimeAdapter {
+@Serializer(forClass = LocalDateTime::class)
-    @ToJson
+object LocalDateTimeAdapter : KSerializer<LocalDateTime> {
-    fun toJson(value: LocalDateTime): String {
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("LocalDateTime", PrimitiveKind.STRING)
-        return DateTimeFormatter.ISO_LOCAL_DATE_TIME.format(value)
+
+    override fun serialize(encoder: Encoder, value: LocalDateTime) {
+        encoder.encodeString(DateTimeFormatter.ISO_LOCAL_DATE_TIME.format(value))
     }
 
-    @FromJson
+    override fun deserialize(decoder: Decoder): LocalDateTime {
-    fun fromJson(value: String): LocalDateTime {
+        return LocalDateTime.parse(decoder.decodeString(), DateTimeFormatter.ISO_LOCAL_DATE_TIME)
-        return LocalDateTime.parse(value, DateTimeFormatter.ISO_LOCAL_DATE_TIME)
     }
-
 }

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/OffsetDateTimeAdapter.kt

@@ -1,19 +1,24 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.FromJson
+import kotlinx.serialization.KSerializer
-import com.squareup.moshi.ToJson
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
 import java.time.OffsetDateTime
 import java.time.format.DateTimeFormatter
 
-class OffsetDateTimeAdapter {
+@Serializer(forClass = OffsetDateTime::class)
-    @ToJson
+object OffsetDateTimeAdapter : KSerializer<OffsetDateTime> {
-    fun toJson(value: OffsetDateTime): String {
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("OffsetDateTime", PrimitiveKind.STRING)
-        return DateTimeFormatter.ISO_OFFSET_DATE_TIME.format(value)
+
+    override fun serialize(encoder: Encoder, value: OffsetDateTime) {
+        encoder.encodeString(DateTimeFormatter.ISO_OFFSET_DATE_TIME.format(value))
     }
 
-    @FromJson
+    override fun deserialize(decoder: Decoder): OffsetDateTime {
-    fun fromJson(value: String): OffsetDateTime {
+        return OffsetDateTime.parse(decoder.decodeString(), DateTimeFormatter.ISO_OFFSET_DATE_TIME)
-        return OffsetDateTime.parse(value, DateTimeFormatter.ISO_OFFSET_DATE_TIME)
     }
-
 }

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt

@@ -1,23 +1,52 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.Moshi
+import java.math.BigDecimal
-import com.squareup.moshi.kotlin.reflect.KotlinJsonAdapterFactory
+import java.math.BigInteger
+import java.time.LocalDate
+import java.time.LocalDateTime
+import java.time.OffsetDateTime
+import java.util.UUID
+import kotlinx.serialization.json.Json
+import kotlinx.serialization.modules.SerializersModule
+import java.net.URI
+import java.net.URL
+import java.util.concurrent.atomic.AtomicBoolean
+import java.util.concurrent.atomic.AtomicInteger
+import java.util.concurrent.atomic.AtomicLong
 
 object Serializer {
+    @Deprecated("Use Serializer.kotlinxSerializationAdapters instead", replaceWith = ReplaceWith("Serializer.kotlinxSerializationAdapters"))
     @JvmStatic
-    val moshiBuilder: Moshi.Builder = Moshi.Builder()
+    val kotlinSerializationAdapters: SerializersModule
-        .add(OffsetDateTimeAdapter())
+        get() { return kotlinxSerializationAdapters }
-        .add(LocalDateTimeAdapter())
-        .add(LocalDateAdapter())
-        .add(UUIDAdapter())
-        .add(ByteArrayAdapter())
-        .add(URIAdapter())
-        .add(KotlinJsonAdapterFactory())
-        .add(BigDecimalAdapter())
-        .add(BigIntegerAdapter())
 
     @JvmStatic
-    val moshi: Moshi by lazy {
+    val kotlinxSerializationAdapters = SerializersModule {
-        moshiBuilder.build()
+        contextual(BigDecimal::class, BigDecimalAdapter)
+        contextual(BigInteger::class, BigIntegerAdapter)
+        contextual(LocalDate::class, LocalDateAdapter)
+        contextual(LocalDateTime::class, LocalDateTimeAdapter)
+        contextual(OffsetDateTime::class, OffsetDateTimeAdapter)
+        contextual(UUID::class, UUIDAdapter)
+        contextual(AtomicInteger::class, AtomicIntegerAdapter)
+        contextual(AtomicLong::class, AtomicLongAdapter)
+        contextual(AtomicBoolean::class, AtomicBooleanAdapter)
+        contextual(URI::class, URIAdapter)
+        contextual(URL::class, URLAdapter)
+        contextual(StringBuilder::class, StringBuilderAdapter)
+    }
+
+    @Deprecated("Use Serializer.kotlinxSerializationJson instead", replaceWith = ReplaceWith("Serializer.kotlinxSerializationJson"))
+    @JvmStatic
+    val jvmJson: Json
+        get() { return kotlinxSerializationJson }
+
+    @JvmStatic
+    val kotlinxSerializationJson: Json by lazy {
+        Json {
+            serializersModule = kotlinxSerializationAdapters
+            ignoreUnknownKeys = true
+            isLenient = true
+        }
     }
 }

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/StringBuilderAdapter.kt

@@ -0,0 +1,20 @@
+package org.openapitools.client.infrastructure
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
+
+@Serializer(forClass = StringBuilder::class)
+object StringBuilderAdapter : KSerializer<StringBuilder> {
+    override fun serialize(encoder: Encoder, value: StringBuilder) {
+        encoder.encodeString(value.toString())
+    }
+
+    override fun deserialize(decoder: Decoder): StringBuilder = StringBuilder(decoder.decodeString())
+
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("StringBuilder", PrimitiveKind.STRING)
+}

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/URIAdapter.kt

@@ -1,13 +1,21 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.FromJson
+import kotlinx.serialization.KSerializer
-import com.squareup.moshi.ToJson
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
 import java.net.URI
 
-class URIAdapter {
+@Serializer(forClass = URI::class)
-    @ToJson
+object URIAdapter : KSerializer<URI> {
-    fun toJson(uri: URI) = uri.toString()
+    override fun serialize(encoder: Encoder, value: URI) {
+        encoder.encodeString(value.toASCIIString())
+    }
 
-    @FromJson
+    override fun deserialize(decoder: Decoder): URI = URI(decoder.decodeString())
-    fun fromJson(s: String): URI = URI.create(s)
+
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("URI", PrimitiveKind.STRING)
 }

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/URLAdapter.kt

@@ -0,0 +1,21 @@
+package org.openapitools.client.infrastructure
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
+import java.net.URL
+
+@Serializer(forClass = URL::class)
+object URLAdapter : KSerializer<URL> {
+    override fun serialize(encoder: Encoder, value: URL) {
+        encoder.encodeString(value.toExternalForm())
+    }
+
+    override fun deserialize(decoder: Decoder): URL = URL(decoder.decodeString())
+
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("URL", PrimitiveKind.STRING)
+}

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/infrastructure/UUIDAdapter.kt

@@ -1,13 +1,23 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.FromJson
+import kotlinx.serialization.KSerializer
-import com.squareup.moshi.ToJson
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
 import java.util.UUID
 
-class UUIDAdapter {
+@Serializer(forClass = UUID::class)
-    @ToJson
+object UUIDAdapter : KSerializer<UUID> {
-    fun toJson(uuid: UUID) = uuid.toString()
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("UUID", PrimitiveKind.STRING)
 
-    @FromJson
+    override fun serialize(encoder: Encoder, value: UUID) {
-    fun fromJson(s: String): UUID = UUID.fromString(s)
+        encoder.encodeString(value.toString())
+    }
+
+    override fun deserialize(decoder: Decoder): UUID {
+        return UUID.fromString(decoder.decodeString())
+    }
 }

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/models/Category.kt

@@ -21,7 +21,14 @@
 package org.openapitools.client.models
 
 
-import com.squareup.moshi.Json
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Contextual
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.builtins.serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
 import android.os.Parcelable
 import kotlinx.parcelize.Parcelize
 
@@ -32,13 +39,13 @@ import kotlinx.parcelize.Parcelize
  * @param name 
  */
 @Parcelize
-
+@Serializable
 data class Category (
 
-    @Json(name = "id")
+    @SerialName(value = "id")
     val id: kotlin.Long? = null,
 
-    @Json(name = "name")
+    @SerialName(value = "name")
     val name: kotlin.String? = null
 
 ) : Parcelable

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/models/ModelApiResponse.kt

@@ -21,7 +21,14 @@
 package org.openapitools.client.models
 
 
-import com.squareup.moshi.Json
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Contextual
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.builtins.serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
 import android.os.Parcelable
 import kotlinx.parcelize.Parcelize
 
@@ -33,16 +40,16 @@ import kotlinx.parcelize.Parcelize
  * @param message 
  */
 @Parcelize
-
+@Serializable
 data class ModelApiResponse (
 
-    @Json(name = "code")
+    @SerialName(value = "code")
     val code: kotlin.Int? = null,
 
-    @Json(name = "type")
+    @SerialName(value = "type")
     val type: kotlin.String? = null,
 
-    @Json(name = "message")
+    @SerialName(value = "message")
     val message: kotlin.String? = null
 
 ) : Parcelable

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/models/Order.kt

@@ -21,7 +21,14 @@
 package org.openapitools.client.models
 
 
-import com.squareup.moshi.Json
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Contextual
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.builtins.serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
 import android.os.Parcelable
 import kotlinx.parcelize.Parcelize
 
@@ -36,26 +43,26 @@ import kotlinx.parcelize.Parcelize
  * @param complete 
  */
 @Parcelize
-
+@Serializable
 data class Order (
 
-    @Json(name = "id")
+    @SerialName(value = "id")
     val id: kotlin.Long? = null,
 
-    @Json(name = "petId")
+    @SerialName(value = "petId")
     val petId: kotlin.Long? = null,
 
-    @Json(name = "quantity")
+    @SerialName(value = "quantity")
     val quantity: kotlin.Int? = null,
 
-    @Json(name = "shipDate")
+    @Contextual @SerialName(value = "shipDate")
     val shipDate: java.time.OffsetDateTime? = null,
 
     /* Order Status */
-    @Json(name = "status")
+    @SerialName(value = "status")
     val status: Order.Status? = null,
 
-    @Json(name = "complete")
+    @SerialName(value = "complete")
     val complete: kotlin.Boolean? = false
 
 ) : Parcelable {
@@ -63,12 +70,29 @@ data class Order (
     /**
      * Order Status
      *
-     * Values: placed,approved,delivered
+     * Values: placed,approved,delivered,unknownDefaultOpenApi
      */
+    @Serializable(with = OrderSerializer::class)
     enum class Status(val value: kotlin.String) {
-        @Json(name = "placed") placed("placed"),
+        @SerialName(value = "placed") placed("placed"),
-        @Json(name = "approved") approved("approved"),
+        @SerialName(value = "approved") approved("approved"),
-        @Json(name = "delivered") delivered("delivered");
+        @SerialName(value = "delivered") delivered("delivered"),
+        @SerialName(value = "unknown_default_open_api") unknownDefaultOpenApi("unknown_default_open_api");
+    }
+
+    @Serializer(forClass = Status::class)
+    internal object StatusSerializer : KSerializer<Status> {
+        override val descriptor = kotlin.String.serializer().descriptor
+
+        override fun deserialize(decoder: Decoder): Status {
+            val value = decoder.decodeSerializableValue(kotlin.String.serializer())
+            return Status.values().firstOrNull { it.value == value }
+                ?: Status.unknownDefaultOpenApi
+        }
+
+        override fun serialize(encoder: Encoder, value: Status) {
+            encoder.encodeSerializableValue(kotlin.String.serializer(), value.value)
+        }
     }
 }
 

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/models/Pet.kt

@@ -23,7 +23,14 @@ package org.openapitools.client.models
 import org.openapitools.client.models.Category
 import org.openapitools.client.models.Tag
 
-import com.squareup.moshi.Json
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Contextual
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.builtins.serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
 import android.os.Parcelable
 import kotlinx.parcelize.Parcelize
 
@@ -38,26 +45,26 @@ import kotlinx.parcelize.Parcelize
  * @param status pet status in the store
  */
 @Parcelize
-
+@Serializable
 data class Pet (
 
-    @Json(name = "name")
+    @SerialName(value = "name")
     val name: kotlin.String,
 
-    @Json(name = "photoUrls")
+    @SerialName(value = "photoUrls")
     val photoUrls: kotlin.collections.List<kotlin.String>,
 
-    @Json(name = "id")
+    @SerialName(value = "id")
     val id: kotlin.Long? = null,
 
-    @Json(name = "category")
+    @SerialName(value = "category")
     val category: Category? = null,
 
-    @Json(name = "tags")
+    @SerialName(value = "tags")
     val tags: kotlin.collections.List<Tag>? = null,
 
     /* pet status in the store */
-    @Json(name = "status")
+    @SerialName(value = "status")
     val status: Pet.Status? = null
 
 ) : Parcelable {
@@ -65,12 +72,29 @@ data class Pet (
     /**
      * pet status in the store
      *
-     * Values: available,pending,sold
+     * Values: available,pending,sold,unknownDefaultOpenApi
      */
+    @Serializable(with = PetSerializer::class)
     enum class Status(val value: kotlin.String) {
-        @Json(name = "available") available("available"),
+        @SerialName(value = "available") available("available"),
-        @Json(name = "pending") pending("pending"),
+        @SerialName(value = "pending") pending("pending"),
-        @Json(name = "sold") sold("sold");
+        @SerialName(value = "sold") sold("sold"),
+        @SerialName(value = "unknown_default_open_api") unknownDefaultOpenApi("unknown_default_open_api");
+    }
+
+    @Serializer(forClass = Status::class)
+    internal object StatusSerializer : KSerializer<Status> {
+        override val descriptor = kotlin.String.serializer().descriptor
+
+        override fun deserialize(decoder: Decoder): Status {
+            val value = decoder.decodeSerializableValue(kotlin.String.serializer())
+            return Status.values().firstOrNull { it.value == value }
+                ?: Status.unknownDefaultOpenApi
+        }
+
+        override fun serialize(encoder: Encoder, value: Status) {
+            encoder.encodeSerializableValue(kotlin.String.serializer(), value.value)
+        }
     }
 }
 

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/models/Tag.kt

@@ -21,7 +21,14 @@
 package org.openapitools.client.models
 
 
-import com.squareup.moshi.Json
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Contextual
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.builtins.serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
 import android.os.Parcelable
 import kotlinx.parcelize.Parcelize
 
@@ -32,13 +39,13 @@ import kotlinx.parcelize.Parcelize
  * @param name 
  */
 @Parcelize
-
+@Serializable
 data class Tag (
 
-    @Json(name = "id")
+    @SerialName(value = "id")
     val id: kotlin.Long? = null,
 
-    @Json(name = "name")
+    @SerialName(value = "name")
     val name: kotlin.String? = null
 
 ) : Parcelable

samples/client/petstore/kotlin-json-request-string/src/main/kotlin/org/openapitools/client/models/User.kt

@@ -21,7 +21,14 @@
 package org.openapitools.client.models
 
 
-import com.squareup.moshi.Json
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Contextual
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.builtins.serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
 import android.os.Parcelable
 import kotlinx.parcelize.Parcelize
 
@@ -38,32 +45,32 @@ import kotlinx.parcelize.Parcelize
  * @param userStatus User Status
  */
 @Parcelize
-
+@Serializable
 data class User (
 
-    @Json(name = "id")
+    @SerialName(value = "id")
     val id: kotlin.Long? = null,
 
-    @Json(name = "username")
+    @SerialName(value = "username")
     val username: kotlin.String? = null,
 
-    @Json(name = "firstName")
+    @SerialName(value = "firstName")
     val firstName: kotlin.String? = null,
 
-    @Json(name = "lastName")
+    @SerialName(value = "lastName")
     val lastName: kotlin.String? = null,
 
-    @Json(name = "email")
+    @SerialName(value = "email")
     val email: kotlin.String? = null,
 
-    @Json(name = "password")
+    @SerialName(value = "password")
     val password: kotlin.String? = null,
 
-    @Json(name = "phone")
+    @SerialName(value = "phone")
     val phone: kotlin.String? = null,
 
     /* User Status */
-    @Json(name = "userStatus")
+    @SerialName(value = "userStatus")
     val userStatus: kotlin.Int? = null
 
 ) : Parcelable

samples/client/petstore/kotlin-retrofit2-kotlinx_serialization/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -16,7 +16,7 @@ import retrofit2.Converter
 import retrofit2.converter.scalars.ScalarsConverterFactory
 
 import com.jakewharton.retrofit2.converter.kotlinx.serialization.asConverterFactory
-import org.openapitools.client.infrastructure.Serializer.jvmJson
+import org.openapitools.client.infrastructure.Serializer.kotlinxSerializationJson
 import okhttp3.MediaType.Companion.toMediaType
 
 class ApiClient(
@@ -32,7 +32,7 @@ class ApiClient(
         Retrofit.Builder()
             .baseUrl(baseUrl)
             .addConverterFactory(ScalarsConverterFactory.create())
-            .addConverterFactory(jvmJson.asConverterFactory("application/json".toMediaType()))
+            .addConverterFactory(kotlinxSerializationJson.asConverterFactory("application/json".toMediaType()))
             .apply {
                 if (converterFactory != null) {
                     addConverterFactory(converterFactory)

samples/client/petstore/kotlin-retrofit2-kotlinx_serialization/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt

@@ -15,8 +15,13 @@ import java.util.concurrent.atomic.AtomicInteger
 import java.util.concurrent.atomic.AtomicLong
 
 object Serializer {
+    @Deprecated("Use Serializer.kotlinxSerializationAdapters instead", replaceWith = ReplaceWith("Serializer.kotlinxSerializationAdapters"))
     @JvmStatic
-    val kotlinSerializationAdapters = SerializersModule {
+    val kotlinSerializationAdapters: SerializersModule
+        get() { return kotlinxSerializationAdapters }
+
+    @JvmStatic
+    val kotlinxSerializationAdapters = SerializersModule {
         contextual(BigDecimal::class, BigDecimalAdapter)
         contextual(BigInteger::class, BigIntegerAdapter)
         contextual(LocalDate::class, LocalDateAdapter)
@@ -31,6 +36,17 @@ object Serializer {
         contextual(StringBuilder::class, StringBuilderAdapter)
     }
 
+    @Deprecated("Use Serializer.kotlinxSerializationJson instead", replaceWith = ReplaceWith("Serializer.kotlinxSerializationJson"))
     @JvmStatic
-    val jvmJson: Json by lazy { Json { serializersModule = kotlinSerializationAdapters } }
+    val jvmJson: Json
+        get() { return kotlinxSerializationJson }
+
+    @JvmStatic
+    val kotlinxSerializationJson: Json by lazy {
+        Json {
+            serializersModule = kotlinxSerializationAdapters
+            ignoreUnknownKeys = true
+            isLenient = true
+        }
+    }
 }

samples/client/petstore/kotlin-uppercase-enum/.openapi-generator/FILES

@@ -6,14 +6,17 @@ gradle/wrapper/gradle-wrapper.jar
 gradle/wrapper/gradle-wrapper.properties
 gradlew
 gradlew.bat
+proguard-rules.pro
 settings.gradle
 src/main/kotlin/org/openapitools/client/apis/EnumApi.kt
 src/main/kotlin/org/openapitools/client/infrastructure/ApiAbstractions.kt
 src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt
 src/main/kotlin/org/openapitools/client/infrastructure/ApiResponse.kt
+src/main/kotlin/org/openapitools/client/infrastructure/AtomicBooleanAdapter.kt
+src/main/kotlin/org/openapitools/client/infrastructure/AtomicIntegerAdapter.kt
+src/main/kotlin/org/openapitools/client/infrastructure/AtomicLongAdapter.kt
 src/main/kotlin/org/openapitools/client/infrastructure/BigDecimalAdapter.kt
 src/main/kotlin/org/openapitools/client/infrastructure/BigIntegerAdapter.kt
-src/main/kotlin/org/openapitools/client/infrastructure/ByteArrayAdapter.kt
 src/main/kotlin/org/openapitools/client/infrastructure/Errors.kt
 src/main/kotlin/org/openapitools/client/infrastructure/LocalDateAdapter.kt
 src/main/kotlin/org/openapitools/client/infrastructure/LocalDateTimeAdapter.kt
@@ -23,6 +26,8 @@ src/main/kotlin/org/openapitools/client/infrastructure/RequestConfig.kt
 src/main/kotlin/org/openapitools/client/infrastructure/RequestMethod.kt
 src/main/kotlin/org/openapitools/client/infrastructure/ResponseExtensions.kt
 src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt
+src/main/kotlin/org/openapitools/client/infrastructure/StringBuilderAdapter.kt
 src/main/kotlin/org/openapitools/client/infrastructure/URIAdapter.kt
+src/main/kotlin/org/openapitools/client/infrastructure/URLAdapter.kt
 src/main/kotlin/org/openapitools/client/infrastructure/UUIDAdapter.kt
 src/main/kotlin/org/openapitools/client/models/PetEnum.kt

samples/client/petstore/kotlin-uppercase-enum/build.gradle

@@ -14,10 +14,12 @@ buildscript {
     }
     dependencies {
         classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+        classpath "org.jetbrains.kotlin:kotlin-serialization:$kotlin_version"
     }
 }
 
 apply plugin: 'kotlin'
+apply plugin: 'kotlinx-serialization'
 
 repositories {
     maven { url "https://repo1.maven.org/maven2" }
@@ -29,9 +31,13 @@ test {
 
 dependencies {
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8:$kotlin_version"
-    implementation "org.jetbrains.kotlin:kotlin-reflect:$kotlin_version"
+    implementation "org.jetbrains.kotlinx:kotlinx-serialization-json:1.2.1"
-    implementation "com.squareup.moshi:moshi-kotlin:1.12.0"
-    implementation "com.squareup.moshi:moshi-adapters:1.12.0"
     implementation "com.squareup.okhttp3:okhttp:4.9.1"
     testImplementation "io.kotlintest:kotlintest-runner-junit5:3.4.2"
 }
+
+tasks.withType(org.jetbrains.kotlin.gradle.tasks.KotlinCompile).configureEach {
+    kotlinOptions {
+        freeCompilerArgs += "-Xopt-in=kotlinx.serialization.ExperimentalSerializationApi"
+    }
+}

samples/client/petstore/kotlin-uppercase-enum/docs/PetEnum.md

@@ -8,5 +8,7 @@
 
     * `MY_SECOND_VALUE` (value: `"MY_SECOND_VALUE"`)
 
+    * `UNKNOWN_DEFAULT_OPEN_API` (value: `"unknown_default_open_api"`)
+
 
 

samples/client/petstore/kotlin-uppercase-enum/proguard-rules.pro

@@ -0,0 +1,11 @@
+-keepattributes *Annotation*, InnerClasses
+-dontnote kotlinx.serialization.AnnotationsKt # core serialization annotations
+
+# kotlinx-serialization-json specific. Add this if you have java.lang.NoClassDefFoundError kotlinx.serialization.json.JsonObjectSerializer
+-keepclassmembers class kotlinx.serialization.json.** { *** Companion; }
+-keepclasseswithmembers class kotlinx.serialization.json.** { kotlinx.serialization.KSerializer serializer(...); }
+
+# project specific.
+-keep,includedescriptorclasses class org.openapitools.client.models.**$$serializer { *; }
+-keepclassmembers class org.openapitools.client.models.** { *** Companion; }
+-keepclasseswithmembers class org.openapitools.client.models.** { kotlinx.serialization.KSerializer serializer(...); }

samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/apis/EnumApi.kt

@@ -25,7 +25,8 @@ import okhttp3.OkHttpClient
 
 import org.openapitools.client.models.PetEnum
 
-import com.squareup.moshi.Json
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
 
 import org.openapitools.client.infrastructure.ApiClient
 import org.openapitools.client.infrastructure.ApiResponse

samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/ApiClient.kt

@@ -27,7 +27,8 @@ import java.time.LocalTime
 import java.time.OffsetDateTime
 import java.time.OffsetTime
 import java.util.Locale
-import com.squareup.moshi.adapter
+import kotlinx.serialization.decodeFromString
+import kotlinx.serialization.encodeToString
 
 open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClient) {
     companion object {
@@ -104,7 +105,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
                 if (content == null) {
                     EMPTY_REQUEST
                 } else {
-                    Serializer.moshi.adapter(T::class.java).toJson(content)
+                    Serializer.kotlinxSerializationJson.encodeToString(content)
                         .toRequestBody((mediaType ?: JsonMediaType).toMediaTypeOrNull())
                 }
             mediaType == XmlMediaType -> throw UnsupportedOperationException("xml not currently supported.")
@@ -112,7 +113,6 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
             else -> throw UnsupportedOperationException("requestBody currently only supports JSON body and File body.")
         }
 
-    @OptIn(ExperimentalStdlibApi::class)
     protected inline fun <reified T: Any?> responseBody(body: ResponseBody?, mediaType: String? = JsonMediaType): T? {
         if(body == null) {
             return null
@@ -135,7 +135,7 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
         }
         return when {
             mediaType==null || (mediaType.startsWith("application/") && mediaType.endsWith("json")) ->
-                Serializer.moshi.adapter<T>().fromJson(bodyContent)
+                Serializer.kotlinxSerializationJson.decodeFromString<T>(bodyContent)
             else ->  throw UnsupportedOperationException("responseBody currently only supports JSON body.")
         }
     }
@@ -237,6 +237,6 @@ open class ApiClient(val baseUrl: String, val client: OkHttpClient = defaultClie
         formatter. It also easily allows to provide a simple way to define a custom date format pattern
         inside a gson/moshi adapter.
         */
-        return Serializer.moshi.adapter(T::class.java).toJson(value).replace("\"", "")
+        return Serializer.kotlinxSerializationJson.encodeToString(value).replace("\"", "")
     }
 }

samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/AtomicBooleanAdapter.kt

@@ -0,0 +1,21 @@
+package org.openapitools.client.infrastructure
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
+import java.util.concurrent.atomic.AtomicBoolean
+
+@Serializer(forClass = AtomicBoolean::class)
+object AtomicBooleanAdapter : KSerializer<AtomicBoolean> {
+    override fun serialize(encoder: Encoder, value: AtomicBoolean) {
+        encoder.encodeBoolean(value.get())
+    }
+
+    override fun deserialize(decoder: Decoder): AtomicBoolean = AtomicBoolean(decoder.decodeBoolean())
+
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("AtomicBoolean", PrimitiveKind.BOOLEAN)
+}

samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/AtomicIntegerAdapter.kt

@@ -0,0 +1,21 @@
+package org.openapitools.client.infrastructure
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
+import java.util.concurrent.atomic.AtomicInteger
+
+@Serializer(forClass = AtomicInteger::class)
+object AtomicIntegerAdapter : KSerializer<AtomicInteger> {
+    override fun serialize(encoder: Encoder, value: AtomicInteger) {
+        encoder.encodeInt(value.get())
+    }
+
+    override fun deserialize(decoder: Decoder): AtomicInteger = AtomicInteger(decoder.decodeInt())
+
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("AtomicInteger", PrimitiveKind.INT)
+}

samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/AtomicLongAdapter.kt

@@ -0,0 +1,21 @@
+package org.openapitools.client.infrastructure
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
+import java.util.concurrent.atomic.AtomicLong
+
+@Serializer(forClass = AtomicLong::class)
+object AtomicLongAdapter : KSerializer<AtomicLong> {
+    override fun serialize(encoder: Encoder, value: AtomicLong) {
+        encoder.encodeLong(value.get())
+    }
+
+    override fun deserialize(decoder: Decoder): AtomicLong = AtomicLong(decoder.decodeLong())
+
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("AtomicLong", PrimitiveKind.LONG)
+}

samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/BigDecimalAdapter.kt

@@ -1,17 +1,17 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.FromJson
+import kotlinx.serialization.KSerializer
-import com.squareup.moshi.ToJson
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
 import java.math.BigDecimal
 
-class BigDecimalAdapter {
+@Serializer(forClass = BigDecimal::class)
-    @ToJson
+object BigDecimalAdapter : KSerializer<BigDecimal> {
-    fun toJson(value: BigDecimal): String {
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("BigDecimal", PrimitiveKind.STRING)
-        return value.toPlainString()
+    override fun deserialize(decoder: Decoder): BigDecimal = BigDecimal(decoder.decodeString())
-    }
+    override fun serialize(encoder: Encoder, value: BigDecimal) = encoder.encodeString(value.toPlainString())
-
-    @FromJson
-    fun fromJson(value: String): BigDecimal {
-        return BigDecimal(value)
-    }
 }

samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/BigIntegerAdapter.kt

@@ -1,17 +1,22 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.FromJson
+import kotlinx.serialization.KSerializer
-import com.squareup.moshi.ToJson
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
 import java.math.BigInteger
 
-class BigIntegerAdapter {
+@Serializer(forClass = BigInteger::class)
-    @ToJson
+object BigIntegerAdapter : KSerializer<BigInteger> {
-    fun toJson(value: BigInteger): String {
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("BigInteger", PrimitiveKind.STRING)
-        return value.toString()
+    override fun deserialize(decoder: Decoder): BigInteger {
+        return BigInteger(decoder.decodeString())
     }
 
-    @FromJson
+    override fun serialize(encoder: Encoder, value: BigInteger) {
-    fun fromJson(value: String): BigInteger {
+        encoder.encodeString(value.toString())
-        return BigInteger(value)
     }
 }

samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/ByteArrayAdapter.kt

@@ -1,12 +0,0 @@
-package org.openapitools.client.infrastructure
-
-import com.squareup.moshi.FromJson
-import com.squareup.moshi.ToJson
-
-class ByteArrayAdapter {
-    @ToJson
-    fun toJson(data: ByteArray): String = String(data)
-
-    @FromJson
-    fun fromJson(data: String): ByteArray = data.toByteArray()
-}

samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/LocalDateAdapter.kt

@@ -1,19 +1,24 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.FromJson
+import kotlinx.serialization.KSerializer
-import com.squareup.moshi.ToJson
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
 import java.time.LocalDate
 import java.time.format.DateTimeFormatter
 
-class LocalDateAdapter {
+@Serializer(forClass = LocalDate::class)
-    @ToJson
+object LocalDateAdapter : KSerializer<LocalDate> {
-    fun toJson(value: LocalDate): String {
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("LocalDate", PrimitiveKind.STRING)
-        return DateTimeFormatter.ISO_LOCAL_DATE.format(value)
+
+    override fun serialize(encoder: Encoder, value: LocalDate) {
+        encoder.encodeString(DateTimeFormatter.ISO_LOCAL_DATE.format(value))
     }
 
-    @FromJson
+    override fun deserialize(decoder: Decoder): LocalDate {
-    fun fromJson(value: String): LocalDate {
+        return LocalDate.parse(decoder.decodeString(), DateTimeFormatter.ISO_LOCAL_DATE)
-        return LocalDate.parse(value, DateTimeFormatter.ISO_LOCAL_DATE)
     }
-
 }

samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/LocalDateTimeAdapter.kt

@@ -1,19 +1,24 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.FromJson
+import kotlinx.serialization.KSerializer
-import com.squareup.moshi.ToJson
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
 import java.time.LocalDateTime
 import java.time.format.DateTimeFormatter
 
-class LocalDateTimeAdapter {
+@Serializer(forClass = LocalDateTime::class)
-    @ToJson
+object LocalDateTimeAdapter : KSerializer<LocalDateTime> {
-    fun toJson(value: LocalDateTime): String {
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("LocalDateTime", PrimitiveKind.STRING)
-        return DateTimeFormatter.ISO_LOCAL_DATE_TIME.format(value)
+
+    override fun serialize(encoder: Encoder, value: LocalDateTime) {
+        encoder.encodeString(DateTimeFormatter.ISO_LOCAL_DATE_TIME.format(value))
     }
 
-    @FromJson
+    override fun deserialize(decoder: Decoder): LocalDateTime {
-    fun fromJson(value: String): LocalDateTime {
+        return LocalDateTime.parse(decoder.decodeString(), DateTimeFormatter.ISO_LOCAL_DATE_TIME)
-        return LocalDateTime.parse(value, DateTimeFormatter.ISO_LOCAL_DATE_TIME)
     }
-
 }

samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/OffsetDateTimeAdapter.kt

@@ -1,19 +1,24 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.FromJson
+import kotlinx.serialization.KSerializer
-import com.squareup.moshi.ToJson
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
 import java.time.OffsetDateTime
 import java.time.format.DateTimeFormatter
 
-class OffsetDateTimeAdapter {
+@Serializer(forClass = OffsetDateTime::class)
-    @ToJson
+object OffsetDateTimeAdapter : KSerializer<OffsetDateTime> {
-    fun toJson(value: OffsetDateTime): String {
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("OffsetDateTime", PrimitiveKind.STRING)
-        return DateTimeFormatter.ISO_OFFSET_DATE_TIME.format(value)
+
+    override fun serialize(encoder: Encoder, value: OffsetDateTime) {
+        encoder.encodeString(DateTimeFormatter.ISO_OFFSET_DATE_TIME.format(value))
     }
 
-    @FromJson
+    override fun deserialize(decoder: Decoder): OffsetDateTime {
-    fun fromJson(value: String): OffsetDateTime {
+        return OffsetDateTime.parse(decoder.decodeString(), DateTimeFormatter.ISO_OFFSET_DATE_TIME)
-        return OffsetDateTime.parse(value, DateTimeFormatter.ISO_OFFSET_DATE_TIME)
     }
-
 }

samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/Serializer.kt

@@ -1,23 +1,52 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.Moshi
+import java.math.BigDecimal
-import com.squareup.moshi.kotlin.reflect.KotlinJsonAdapterFactory
+import java.math.BigInteger
+import java.time.LocalDate
+import java.time.LocalDateTime
+import java.time.OffsetDateTime
+import java.util.UUID
+import kotlinx.serialization.json.Json
+import kotlinx.serialization.modules.SerializersModule
+import java.net.URI
+import java.net.URL
+import java.util.concurrent.atomic.AtomicBoolean
+import java.util.concurrent.atomic.AtomicInteger
+import java.util.concurrent.atomic.AtomicLong
 
 object Serializer {
+    @Deprecated("Use Serializer.kotlinxSerializationAdapters instead", replaceWith = ReplaceWith("Serializer.kotlinxSerializationAdapters"))
     @JvmStatic
-    val moshiBuilder: Moshi.Builder = Moshi.Builder()
+    val kotlinSerializationAdapters: SerializersModule
-        .add(OffsetDateTimeAdapter())
+        get() { return kotlinxSerializationAdapters }
-        .add(LocalDateTimeAdapter())
-        .add(LocalDateAdapter())
-        .add(UUIDAdapter())
-        .add(ByteArrayAdapter())
-        .add(URIAdapter())
-        .add(KotlinJsonAdapterFactory())
-        .add(BigDecimalAdapter())
-        .add(BigIntegerAdapter())
 
     @JvmStatic
-    val moshi: Moshi by lazy {
+    val kotlinxSerializationAdapters = SerializersModule {
-        moshiBuilder.build()
+        contextual(BigDecimal::class, BigDecimalAdapter)
+        contextual(BigInteger::class, BigIntegerAdapter)
+        contextual(LocalDate::class, LocalDateAdapter)
+        contextual(LocalDateTime::class, LocalDateTimeAdapter)
+        contextual(OffsetDateTime::class, OffsetDateTimeAdapter)
+        contextual(UUID::class, UUIDAdapter)
+        contextual(AtomicInteger::class, AtomicIntegerAdapter)
+        contextual(AtomicLong::class, AtomicLongAdapter)
+        contextual(AtomicBoolean::class, AtomicBooleanAdapter)
+        contextual(URI::class, URIAdapter)
+        contextual(URL::class, URLAdapter)
+        contextual(StringBuilder::class, StringBuilderAdapter)
+    }
+
+    @Deprecated("Use Serializer.kotlinxSerializationJson instead", replaceWith = ReplaceWith("Serializer.kotlinxSerializationJson"))
+    @JvmStatic
+    val jvmJson: Json
+        get() { return kotlinxSerializationJson }
+
+    @JvmStatic
+    val kotlinxSerializationJson: Json by lazy {
+        Json {
+            serializersModule = kotlinxSerializationAdapters
+            ignoreUnknownKeys = true
+            isLenient = true
+        }
     }
 }

samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/StringBuilderAdapter.kt

@@ -0,0 +1,20 @@
+package org.openapitools.client.infrastructure
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
+
+@Serializer(forClass = StringBuilder::class)
+object StringBuilderAdapter : KSerializer<StringBuilder> {
+    override fun serialize(encoder: Encoder, value: StringBuilder) {
+        encoder.encodeString(value.toString())
+    }
+
+    override fun deserialize(decoder: Decoder): StringBuilder = StringBuilder(decoder.decodeString())
+
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("StringBuilder", PrimitiveKind.STRING)
+}

samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/URIAdapter.kt

@@ -1,13 +1,21 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.FromJson
+import kotlinx.serialization.KSerializer
-import com.squareup.moshi.ToJson
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
 import java.net.URI
 
-class URIAdapter {
+@Serializer(forClass = URI::class)
-    @ToJson
+object URIAdapter : KSerializer<URI> {
-    fun toJson(uri: URI) = uri.toString()
+    override fun serialize(encoder: Encoder, value: URI) {
+        encoder.encodeString(value.toASCIIString())
+    }
 
-    @FromJson
+    override fun deserialize(decoder: Decoder): URI = URI(decoder.decodeString())
-    fun fromJson(s: String): URI = URI.create(s)
+
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("URI", PrimitiveKind.STRING)
 }

samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/URLAdapter.kt

@@ -0,0 +1,21 @@
+package org.openapitools.client.infrastructure
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
+import java.net.URL
+
+@Serializer(forClass = URL::class)
+object URLAdapter : KSerializer<URL> {
+    override fun serialize(encoder: Encoder, value: URL) {
+        encoder.encodeString(value.toExternalForm())
+    }
+
+    override fun deserialize(decoder: Decoder): URL = URL(decoder.decodeString())
+
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("URL", PrimitiveKind.STRING)
+}

samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/infrastructure/UUIDAdapter.kt

@@ -1,13 +1,23 @@
 package org.openapitools.client.infrastructure
 
-import com.squareup.moshi.FromJson
+import kotlinx.serialization.KSerializer
-import com.squareup.moshi.ToJson
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.descriptors.PrimitiveSerialDescriptor
+import kotlinx.serialization.descriptors.PrimitiveKind
+import kotlinx.serialization.descriptors.SerialDescriptor
 import java.util.UUID
 
-class UUIDAdapter {
+@Serializer(forClass = UUID::class)
-    @ToJson
+object UUIDAdapter : KSerializer<UUID> {
-    fun toJson(uuid: UUID) = uuid.toString()
+    override val descriptor: SerialDescriptor = PrimitiveSerialDescriptor("UUID", PrimitiveKind.STRING)
 
-    @FromJson
+    override fun serialize(encoder: Encoder, value: UUID) {
-    fun fromJson(s: String): UUID = UUID.fromString(s)
+        encoder.encodeString(value.toString())
+    }
+
+    override fun deserialize(decoder: Decoder): UUID {
+        return UUID.fromString(decoder.decodeString())
+    }
 }

samples/client/petstore/kotlin-uppercase-enum/src/main/kotlin/org/openapitools/client/models/PetEnum.kt

@@ -21,21 +21,30 @@
 package org.openapitools.client.models
 
 
-import com.squareup.moshi.Json
+import kotlinx.serialization.SerialName
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.builtins.serializer
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
 
 /**
  * An enum with complex-ish naming
  *
- * Values: MY_FIRST_VALUE,MY_SECOND_VALUE
+ * Values: MY_FIRST_VALUE,MY_SECOND_VALUE,UNKNOWN_DEFAULT_OPEN_API
  */
-
+@Serializable(with = PetEnumSerializer::class)
 enum class PetEnum(val value: kotlin.String) {
 
-    @Json(name = "myFirstValue")
+    @SerialName(value = "myFirstValue")
     MY_FIRST_VALUE("myFirstValue"),
 
-    @Json(name = "MY_SECOND_VALUE")
+    @SerialName(value = "MY_SECOND_VALUE")
-    MY_SECOND_VALUE("MY_SECOND_VALUE");
+    MY_SECOND_VALUE("MY_SECOND_VALUE"),
+
+    @SerialName(value = "unknown_default_open_api")
+    UNKNOWN_DEFAULT_OPEN_API("unknown_default_open_api");
 
     /**
      * Override toString() to avoid using the enum variable name as the value, and instead use
@@ -64,3 +73,18 @@ enum class PetEnum(val value: kotlin.String) {
     }
 }
 
+@Serializer(forClass = PetEnum::class)
+internal object PetEnumSerializer : KSerializer<PetEnum> {
+    override val descriptor = kotlin.String.serializer().descriptor
+
+    override fun deserialize(decoder: Decoder): PetEnum {
+        val value = decoder.decodeSerializableValue(kotlin.String.serializer())
+        return PetEnum.values().firstOrNull { it.value == value }
+            ?: PetEnum.UNKNOWN_DEFAULT_OPEN_API
+    }
+
+    override fun serialize(encoder: Encoder, value: PetEnum) {
+        encoder.encodeSerializableValue(kotlin.String.serializer(), value.value)
+    }
+}
+