From 87ee5fff02e1d21507618a9eda2a13b239deab70 Mon Sep 17 00:00:00 2001
From: Hidde Wieringa <hidde@hiddewieringa.nl>
Date: Sun, 23 May 2021 18:59:35 +0200
Subject: [PATCH 01/13] Add Kotlin serializer and basic test

---
 .../kotlin/serialization/KotlinSerializer.kt  | 177 ++++++++++++++++++
 .../serialization/KotlinSerializerTest.kt     |  91 +++++++++
 pom.xml                                       |  16 +-
 3 files changed, 283 insertions(+), 1 deletion(-)
 create mode 100644 kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
 create mode 100644 kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt

diff --git a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
new file mode 100644
index 00000000..35094d2f
--- /dev/null
+++ b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
@@ -0,0 +1,177 @@
+/*
+ * Copyright (c) 2010-2020. Axon Framework
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.axonframework.extensions.kotlin.serialization
+
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.SerializationException
+import kotlinx.serialization.json.Json
+import kotlinx.serialization.json.JsonElement
+import org.axonframework.common.ObjectUtils
+import org.axonframework.serialization.AnnotationRevisionResolver
+import org.axonframework.serialization.ChainingConverter
+import org.axonframework.serialization.Converter
+import org.axonframework.serialization.RevisionResolver
+import org.axonframework.serialization.SerializedObject
+import org.axonframework.serialization.SerializedType
+import org.axonframework.serialization.Serializer
+import org.axonframework.serialization.SimpleSerializedObject
+import org.axonframework.serialization.SimpleSerializedType
+import org.axonframework.serialization.UnknownSerializedType
+import kotlin.reflect.KClass
+import kotlin.reflect.full.companionObject
+import kotlin.reflect.full.companionObjectInstance
+
+/**
+ * Implementation of Axon Serializer that uses a kotlinx.serialization implementation.
+ * The serialized format is JSON.
+ *
+ * @see kotlinx.serialization.Serializer
+ * @see org.axonframework.serialization.Serializer
+ */
+class KotlinSerializer(
+    private val revisionResolver: RevisionResolver,
+    private val converter: Converter,
+    private val json: Json
+) : Serializer {
+
+    private val serializerCache: MutableMap<Class<*>, KSerializer<*>> = mutableMapOf()
+
+    override fun <T> serialize(`object`: Any?, expectedRepresentation: Class<T>): SerializedObject<T> {
+        try {
+            val type = ObjectUtils.nullSafeTypeOf(`object`)
+            val serializer: KSerializer<Any?> = type.serializer()
+            return when {
+                expectedRepresentation.isAssignableFrom(String::class.java) ->
+                    SimpleSerializedObject(
+                        json.encodeToString(serializer, `object`) as T,
+                        expectedRepresentation,
+                        typeForClass(type)
+                    )
+
+                expectedRepresentation.isAssignableFrom(JsonElement::class.java) ->
+                    SimpleSerializedObject(
+                        json.encodeToJsonElement(serializer, `object`) as T,
+                        expectedRepresentation,
+                        typeForClass(type)
+                    )
+
+                else ->
+                    throw org.axonframework.serialization.SerializationException("Cannot serialize type $type to representation $expectedRepresentation. String and JsonElement are supported.")
+            }
+        } catch (ex: SerializationException) {
+            throw org.axonframework.serialization.SerializationException("Cannot serialize type ${`object`?.javaClass?.name} to representation $expectedRepresentation.", ex)
+        }
+    }
+
+    override fun <T> canSerializeTo(expectedRepresentation: Class<T>): Boolean =
+        expectedRepresentation == String::class.java ||
+                expectedRepresentation == JsonElement::class.java
+
+    override fun <S, T> deserialize(serializedObject: SerializedObject<S>?): T? {
+        try {
+            if (serializedObject == null) {
+                return null
+            }
+
+            if (serializedObject.type == SerializedType.emptyType()) {
+                return null
+            }
+
+            val serializer: KSerializer<T> = serializedObject.serializer()
+            return when {
+                serializedObject.contentType.isAssignableFrom(String::class.java) ->
+                    json.decodeFromString(serializer, serializedObject.data as String)
+
+                serializedObject.contentType.isAssignableFrom(JsonElement::class.java) ->
+                    json.decodeFromJsonElement(serializer, serializedObject.data as JsonElement)
+
+                else ->
+                    throw org.axonframework.serialization.SerializationException("Cannot deserialize from content type ${serializedObject.contentType} to type ${serializedObject.type}. String and JsonElement are supported.")
+            }
+        } catch (ex: SerializationException) {
+            throw org.axonframework.serialization.SerializationException(
+                "Could not deserialize from content type ${serializedObject?.contentType} to type ${serializedObject?.type}",
+                ex
+            )
+        }
+    }
+
+    private fun <S, T> SerializedObject<S>.serializer(): KSerializer<T> =
+        classForType(type).serializer() as KSerializer<T>
+
+    /**
+     * When a type is compiled by the Kotlin compiler extension, a companion object
+     * is created which contains a method `serializer()`. This method should be called
+     * to get the serializer of the class.
+     *
+     * In a 'normal' serialization environment, you would call the MyClass.serializer()
+     * method directly. Here we are in a generic setting, and need reflection to call
+     * the method.
+     *
+     * This method caches the reflection mapping from class to serializer for efficiency.
+     */
+    private fun <T> Class<T>.serializer(): KSerializer<T> =
+        serializerCache.computeIfAbsent(this) {
+            // Class<T>: T must be non-null
+            val kClass = (this as Class<Any>).kotlin
+
+            val companion = kClass.companionObject
+                ?: throw SerializationException("Class $this has no companion object. Did you mark it as @Serializable?")
+
+            val serializerMethod = companion.java.getMethod("serializer")
+                ?: throw SerializationException("Class $this has no serializer() method. Did you mark it as @Serializable?")
+
+            serializerMethod.invoke(kClass.companionObjectInstance) as KSerializer<*>
+        } as KSerializer<T>
+
+    override fun classForType(type: SerializedType): Class<*> =
+        if (SerializedType.emptyType() == type) {
+            Void.TYPE
+        } else {
+            try {
+                Class.forName(type.name)
+            } catch (e: ClassNotFoundException) {
+                UnknownSerializedType::class.java
+            }
+        }
+
+    override fun typeForClass(type: Class<*>): SerializedType =
+        SimpleSerializedType(type.name, revisionOf(type))
+
+    private fun revisionOf(type: Class<*>): String? =
+        revisionResolver.revisionOf(type)
+
+    override fun getConverter(): Converter =
+        converter
+
+}
+
+class KotlinSerializerConfiguration {
+    var revisionResolver: RevisionResolver = AnnotationRevisionResolver()
+    var converter: Converter = ChainingConverter()
+    var json: Json = Json
+}
+
+fun kotlinSerializer(init: KotlinSerializerConfiguration.() -> Unit = {}): KotlinSerializer {
+    val configuration = KotlinSerializerConfiguration()
+    configuration.init()
+    return KotlinSerializer(
+        configuration.revisionResolver,
+        configuration.converter,
+        configuration.json,
+    )
+}
\ No newline at end of file
diff --git a/kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt b/kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt
new file mode 100644
index 00000000..7337f132
--- /dev/null
+++ b/kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt
@@ -0,0 +1,91 @@
+package org.axonframework.extensions.kotlin.serialization
+
+import kotlinx.serialization.Serializable
+import kotlinx.serialization.json.Json
+import kotlinx.serialization.json.JsonElement
+import org.axonframework.serialization.AnnotationRevisionResolver
+import org.axonframework.serialization.ChainingConverter
+import org.axonframework.serialization.SerializedType
+import org.axonframework.serialization.SimpleSerializedObject
+import org.junit.jupiter.api.Assertions.assertEquals
+import org.junit.jupiter.api.Assertions.assertTrue
+import org.junit.jupiter.api.Test
+import kotlin.test.assertNotNull
+import kotlin.test.assertNull
+
+class KotlinSerializerTest {
+
+    /**
+     * This class will automatically become serializable through the Kotlin serialization compiler plugin.
+     */
+    @Serializable
+    data class TestData(
+        val name: String,
+        val value: Float?
+    )
+
+    @Test
+    fun canSerializeTo() {
+        val serializer = kotlinSerializer()
+
+        assertTrue(serializer.canSerializeTo(String::class.java))
+        assertTrue(serializer.canSerializeTo(JsonElement::class.java))
+    }
+
+    @Test
+    fun `configuration options`() {
+        val serializer = kotlinSerializer {
+            json = Json
+            converter = ChainingConverter()
+            revisionResolver = AnnotationRevisionResolver()
+        }
+        assertNotNull(serializer)
+    }
+
+    @Test
+    fun serialize() {
+        val serializer = kotlinSerializer()
+
+        val emptySerialized = serializer.serialize(TestData("", null), String::class.java)
+        assertEquals("SimpleSerializedType[org.axonframework.extensions.kotlin.serialization.KotlinSerializerTest\$TestData] (revision null)", emptySerialized.type.toString())
+        assertEquals("""{"name":"","value":null}""", emptySerialized.data)
+        assertEquals(String::class.java, emptySerialized.contentType)
+
+        val filledSerialized = serializer.serialize(TestData("name", 1.23f), String::class.java)
+        assertEquals("SimpleSerializedType[org.axonframework.extensions.kotlin.serialization.KotlinSerializerTest\$TestData] (revision null)", filledSerialized.type.toString())
+        assertEquals("""{"name":"name","value":1.23}""", filledSerialized.data)
+        assertEquals(String::class.java, filledSerialized.contentType)
+    }
+
+    @Test
+    fun deserialize() {
+        val serializer = kotlinSerializer()
+
+        val nullDeserialized: Any? = serializer.deserialize(SimpleSerializedObject(
+            "",
+            String::class.java,
+            SerializedType.emptyType()
+        ))
+        assertNull(nullDeserialized)
+
+        val emptyDeserialized: Any? = serializer.deserialize(SimpleSerializedObject(
+            """{"name":"","value":null}""",
+            String::class.java,
+            TestData::class.java.name,
+            null
+        ))
+        assertNotNull(emptyDeserialized as TestData)
+        assertEquals(emptyDeserialized.name, "")
+        assertEquals(emptyDeserialized.value, null)
+
+        val filledDeserialized: Any? = serializer.deserialize(SimpleSerializedObject(
+            """{"name":"name","value":1.23}""",
+            String::class.java,
+            TestData::class.java.name,
+            null
+        ))
+        assertNotNull(filledDeserialized as TestData)
+        assertEquals(filledDeserialized.name, "name")
+        assertEquals(filledDeserialized.value, 1.23f)
+    }
+}
\ No newline at end of file
diff --git a/pom.xml b/pom.xml
index 319c361e..c8438252 100644
--- a/pom.xml
+++ b/pom.xml
@@ -34,8 +34,9 @@
   <properties>
     <axon.version>4.5</axon.version>
     <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
-    <kotlin.version>1.4.32</kotlin.version>
+    <kotlin.version>1.5.0</kotlin.version>
     <kotlin-logging.version>2.0.6</kotlin-logging.version>
+    <kotlin-serialization.version>1.2.1</kotlin-serialization.version>
     <jackson-kotlin.version>2.12.3</jackson-kotlin.version>
     <mockk.version>1.11.0</mockk.version>
     <junit.jupiter.version>5.7.2</junit.jupiter.version>
@@ -130,6 +131,13 @@
       <scope>test</scope>
     </dependency>
 
+    <!-- Serialization -->
+    <dependency>
+      <groupId>org.jetbrains.kotlinx</groupId>
+      <artifactId>kotlinx-serialization-json</artifactId>
+      <version>${kotlin-serialization.version}</version>
+    </dependency>
+
     <!-- Test dependencies -->
     <dependency>
       <groupId>org.junit.jupiter</groupId>
@@ -434,6 +442,7 @@
             <compilerPlugins>
               <plugin>no-arg</plugin>
               <plugin>all-open</plugin>
+              <plugin>kotlinx-serialization</plugin>
             </compilerPlugins>
             <pluginOptions>
               <!-- Axon specific classes -->
@@ -477,6 +486,11 @@
               <artifactId>kotlin-maven-noarg</artifactId>
               <version>${kotlin.version}</version>
             </dependency>
+            <dependency>
+              <groupId>org.jetbrains.kotlin</groupId>
+              <artifactId>kotlin-maven-serialization</artifactId>
+              <version>${kotlin.version}</version>
+            </dependency>
           </dependencies>
         </plugin>
       </plugins>

From 43c5d0e8e8167f65c0e61ba48a8e47cc59b1dc19 Mon Sep 17 00:00:00 2001
From: Hidde Wieringa <hidde@hiddewieringa.nl>
Date: Sun, 30 May 2021 16:46:12 +0200
Subject: [PATCH 02/13] Comments: - Dependencies with optional mark - Add test
 case (and code fixes) for nullable serializer code - 2021 license

---
 .../kotlin/serialization/KotlinSerializer.kt  | 48 +++++++++++++++----
 .../serialization/KotlinSerializerTest.kt     |  4 ++
 pom.xml                                       |  2 +
 3 files changed, 44 insertions(+), 10 deletions(-)

diff --git a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
index 35094d2f..ec81abab 100644
--- a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
+++ b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2010-2020. Axon Framework
+ * Copyright (c) 2010-2021. Axon Framework
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -20,6 +20,7 @@ import kotlinx.serialization.KSerializer
 import kotlinx.serialization.SerializationException
 import kotlinx.serialization.json.Json
 import kotlinx.serialization.json.JsonElement
+import kotlinx.serialization.json.JsonNull
 import org.axonframework.common.ObjectUtils
 import org.axonframework.serialization.AnnotationRevisionResolver
 import org.axonframework.serialization.ChainingConverter
@@ -31,7 +32,6 @@ import org.axonframework.serialization.Serializer
 import org.axonframework.serialization.SimpleSerializedObject
 import org.axonframework.serialization.SimpleSerializedType
 import org.axonframework.serialization.UnknownSerializedType
-import kotlin.reflect.KClass
 import kotlin.reflect.full.companionObject
 import kotlin.reflect.full.companionObjectInstance
 
@@ -39,8 +39,12 @@ import kotlin.reflect.full.companionObjectInstance
  * Implementation of Axon Serializer that uses a kotlinx.serialization implementation.
  * The serialized format is JSON.
  *
+ * The DSL function kotlinSerializer can be used to easily configure the parameters
+ * for this serializer.
+ *
  * @see kotlinx.serialization.Serializer
  * @see org.axonframework.serialization.Serializer
+ * @see kotlinSerializer
  */
 class KotlinSerializer(
     private val revisionResolver: RevisionResolver,
@@ -50,21 +54,20 @@ class KotlinSerializer(
 
     private val serializerCache: MutableMap<Class<*>, KSerializer<*>> = mutableMapOf()
 
-    override fun <T> serialize(`object`: Any?, expectedRepresentation: Class<T>): SerializedObject<T> {
+    override fun <T> serialize(value: Any?, expectedRepresentation: Class<T>): SerializedObject<T> {
         try {
-            val type = ObjectUtils.nullSafeTypeOf(`object`)
-            val serializer: KSerializer<Any?> = type.serializer()
+            val type = ObjectUtils.nullSafeTypeOf(value)
             return when {
                 expectedRepresentation.isAssignableFrom(String::class.java) ->
                     SimpleSerializedObject(
-                        json.encodeToString(serializer, `object`) as T,
+                        (if (value == null) "null" else json.encodeToString(type.serializer(), value)) as T,
                         expectedRepresentation,
                         typeForClass(type)
                     )
 
                 expectedRepresentation.isAssignableFrom(JsonElement::class.java) ->
                     SimpleSerializedObject(
-                        json.encodeToJsonElement(serializer, `object`) as T,
+                        (if (value == null) JsonNull else json.encodeToJsonElement(type.serializer(), value)) as T,
                         expectedRepresentation,
                         typeForClass(type)
                     )
@@ -73,7 +76,7 @@ class KotlinSerializer(
                     throw org.axonframework.serialization.SerializationException("Cannot serialize type $type to representation $expectedRepresentation. String and JsonElement are supported.")
             }
         } catch (ex: SerializationException) {
-            throw org.axonframework.serialization.SerializationException("Cannot serialize type ${`object`?.javaClass?.name} to representation $expectedRepresentation.", ex)
+            throw org.axonframework.serialization.SerializationException("Cannot serialize type ${value?.javaClass?.name} to representation $expectedRepresentation.", ex)
         }
     }
 
@@ -149,8 +152,12 @@ class KotlinSerializer(
             }
         }
 
-    override fun typeForClass(type: Class<*>): SerializedType =
-        SimpleSerializedType(type.name, revisionOf(type))
+    override fun typeForClass(type: Class<*>?): SerializedType =
+        if (type == null || Void.TYPE == type || Void::class.java == type) {
+            SimpleSerializedType.emptyType()
+        } else {
+            SimpleSerializedType(type.name, revisionResolver.revisionOf(type))
+        }
 
     private fun revisionOf(type: Class<*>): String? =
         revisionResolver.revisionOf(type)
@@ -160,12 +167,33 @@ class KotlinSerializer(
 
 }
 
+/**
+ * Configuration which will be used to construct a KotlinSerializer.
+ * This class is used in the kotlinSerializer DSL function.
+ *
+ * @see KotlinSerializer
+ * @see kotlinSerializer
+ */
 class KotlinSerializerConfiguration {
     var revisionResolver: RevisionResolver = AnnotationRevisionResolver()
     var converter: Converter = ChainingConverter()
     var json: Json = Json
 }
 
+/**
+ * DSL function to configure a new KotlinSerializer.
+ *
+ * Usage example:
+ * <code>
+ *     val serializer: KotlinSerializer = kotlinSerializer {
+ *          json = Json
+ *          converter = ChainingConverter()
+ *          revisionResolver = AnnotationRevisionResolver()
+ *     }
+ * </code>
+ *
+ * @see KotlinSerializer
+ */
 fun kotlinSerializer(init: KotlinSerializerConfiguration.() -> Unit = {}): KotlinSerializer {
     val configuration = KotlinSerializerConfiguration()
     configuration.init()
diff --git a/kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt b/kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt
index 7337f132..1843acb9 100644
--- a/kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt
+++ b/kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt
@@ -55,6 +55,10 @@ class KotlinSerializerTest {
         assertEquals("SimpleSerializedType[org.axonframework.extensions.kotlin.serialization.KotlinSerializerTest\$TestData] (revision null)", filledSerialized.type.toString())
         assertEquals("""{"name":"name","value":1.23}""", filledSerialized.data)
         assertEquals(String::class.java, filledSerialized.contentType)
+
+        val nullSerialized = serializer.serialize(null, String::class.java)
+        assertEquals("null", nullSerialized.data)
+        assertEquals(String::class.java, nullSerialized.contentType)
     }
 
     @Test
diff --git a/pom.xml b/pom.xml
index c8438252..de1967c7 100644
--- a/pom.xml
+++ b/pom.xml
@@ -136,6 +136,7 @@
       <groupId>org.jetbrains.kotlinx</groupId>
       <artifactId>kotlinx-serialization-json</artifactId>
       <version>${kotlin-serialization.version}</version>
+      <optional>true</optional>
     </dependency>
 
     <!-- Test dependencies -->
@@ -490,6 +491,7 @@
               <groupId>org.jetbrains.kotlin</groupId>
               <artifactId>kotlin-maven-serialization</artifactId>
               <version>${kotlin.version}</version>
+              <optional>true</optional>
             </dependency>
           </dependencies>
         </plugin>

From 2b7735b8b85f568b2c02eec3469576cb9be28aa4 Mon Sep 17 00:00:00 2001
From: Hidde Wieringa <hidde@hiddewieringa.nl>
Date: Thu, 3 Jun 2021 19:42:22 +0200
Subject: [PATCH 03/13] Add defaults

---
 .../extensions/kotlin/serialization/KotlinSerializer.kt       | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
index ec81abab..d63e8c01 100644
--- a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
+++ b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
@@ -47,8 +47,8 @@ import kotlin.reflect.full.companionObjectInstance
  * @see kotlinSerializer
  */
 class KotlinSerializer(
-    private val revisionResolver: RevisionResolver,
-    private val converter: Converter,
+    private val revisionResolver: RevisionResolver = AnnotationRevisionResolver(),
+    private val converter: Converter = ChainingConverter(),
     private val json: Json
 ) : Serializer {
 

From 1256d2d65a2425ab1a8958054473705de6ee7a0e Mon Sep 17 00:00:00 2001
From: Hidde Wieringa <hidde@hiddewieringa.nl>
Date: Thu, 3 Jun 2021 19:42:28 +0200
Subject: [PATCH 04/13] Add since and author

---
 .../extensions/kotlin/serialization/KotlinSerializer.kt        | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
index d63e8c01..6da155fc 100644
--- a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
+++ b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
@@ -45,6 +45,9 @@ import kotlin.reflect.full.companionObjectInstance
  * @see kotlinx.serialization.Serializer
  * @see org.axonframework.serialization.Serializer
  * @see kotlinSerializer
+ *
+ * @since 0.2.0
+ * @author Hidde Wieringa
  */
 class KotlinSerializer(
     private val revisionResolver: RevisionResolver = AnnotationRevisionResolver(),

From f7d4ee9f6cc1f1d91f8dd3e2ba3b831162dc6e48 Mon Sep 17 00:00:00 2001
From: Hidde Wieringa <hidde@hiddewieringa.nl>
Date: Thu, 3 Jun 2021 19:53:01 +0200
Subject: [PATCH 05/13] Handle unknown serialized type

---
 .../kotlin/serialization/KotlinSerializer.kt     | 16 +++++++++++-----
 1 file changed, 11 insertions(+), 5 deletions(-)

diff --git a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
index 6da155fc..69383740 100644
--- a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
+++ b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
@@ -34,6 +34,7 @@ import org.axonframework.serialization.SimpleSerializedType
 import org.axonframework.serialization.UnknownSerializedType
 import kotlin.reflect.full.companionObject
 import kotlin.reflect.full.companionObjectInstance
+import org.axonframework.serialization.SerializationException as AxonSerializationException
 
 /**
  * Implementation of Axon Serializer that uses a kotlinx.serialization implementation.
@@ -76,10 +77,10 @@ class KotlinSerializer(
                     )
 
                 else ->
-                    throw org.axonframework.serialization.SerializationException("Cannot serialize type $type to representation $expectedRepresentation. String and JsonElement are supported.")
+                    throw AxonSerializationException("Cannot serialize type $type to representation $expectedRepresentation. String and JsonElement are supported.")
             }
         } catch (ex: SerializationException) {
-            throw org.axonframework.serialization.SerializationException("Cannot serialize type ${value?.javaClass?.name} to representation $expectedRepresentation.", ex)
+            throw AxonSerializationException("Cannot serialize type ${value?.javaClass?.name} to representation $expectedRepresentation.", ex)
         }
     }
 
@@ -97,7 +98,12 @@ class KotlinSerializer(
                 return null
             }
 
-            val serializer: KSerializer<T> = serializedObject.serializer()
+            val foundType = classForType(serializedObject.type)
+            if (UnknownSerializedType::class.java.isAssignableFrom(foundType)) {
+                return UnknownSerializedType(this, serializedObject) as T
+            }
+
+            val serializer: KSerializer<T> = foundType.serializer() as KSerializer<T>
             return when {
                 serializedObject.contentType.isAssignableFrom(String::class.java) ->
                     json.decodeFromString(serializer, serializedObject.data as String)
@@ -106,10 +112,10 @@ class KotlinSerializer(
                     json.decodeFromJsonElement(serializer, serializedObject.data as JsonElement)
 
                 else ->
-                    throw org.axonframework.serialization.SerializationException("Cannot deserialize from content type ${serializedObject.contentType} to type ${serializedObject.type}. String and JsonElement are supported.")
+                    throw AxonSerializationException("Cannot deserialize from content type ${serializedObject.contentType} to type ${serializedObject.type}. String and JsonElement are supported.")
             }
         } catch (ex: SerializationException) {
-            throw org.axonframework.serialization.SerializationException(
+            throw AxonSerializationException(
                 "Could not deserialize from content type ${serializedObject?.contentType} to type ${serializedObject?.type}",
                 ex
             )

From 798b3fd031354e2a46fbedb2b378bbf3694d14f4 Mon Sep 17 00:00:00 2001
From: Hidde Wieringa <hidde@hiddewieringa.nl>
Date: Thu, 3 Jun 2021 20:48:20 +0200
Subject: [PATCH 06/13] Custom serializer

---
 .../kotlin/serialization/KotlinSerializer.kt  | 12 +--
 .../serializer/ConfigTokenSerializer.kt       | 49 +++++++++++++
 .../serialization/KotlinSerializerTest.kt     | 73 ++++++++++++++-----
 3 files changed, 112 insertions(+), 22 deletions(-)
 create mode 100644 kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/serializer/ConfigTokenSerializer.kt

diff --git a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
index 69383740..085798a2 100644
--- a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
+++ b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
@@ -16,6 +16,7 @@
 
 package org.axonframework.extensions.kotlin.serialization
 
+import kotlinx.serialization.ContextualSerializer
 import kotlinx.serialization.KSerializer
 import kotlinx.serialization.SerializationException
 import kotlinx.serialization.json.Json
@@ -134,6 +135,10 @@ class KotlinSerializer(
      * method directly. Here we are in a generic setting, and need reflection to call
      * the method.
      *
+     * If there is no `serializer` method, a ContextualSerializer will be created. This
+     * serializer requires manual configuration of the SerializersModule containing a
+     * KSerializer which will be used when this class is serialized.
+     *
      * This method caches the reflection mapping from class to serializer for efficiency.
      */
     private fun <T> Class<T>.serializer(): KSerializer<T> =
@@ -142,10 +147,10 @@ class KotlinSerializer(
             val kClass = (this as Class<Any>).kotlin
 
             val companion = kClass.companionObject
-                ?: throw SerializationException("Class $this has no companion object. Did you mark it as @Serializable?")
+                ?: return@computeIfAbsent ContextualSerializer(kClass)
 
             val serializerMethod = companion.java.getMethod("serializer")
-                ?: throw SerializationException("Class $this has no serializer() method. Did you mark it as @Serializable?")
+                ?: return@computeIfAbsent ContextualSerializer(kClass)
 
             serializerMethod.invoke(kClass.companionObjectInstance) as KSerializer<*>
         } as KSerializer<T>
@@ -168,9 +173,6 @@ class KotlinSerializer(
             SimpleSerializedType(type.name, revisionResolver.revisionOf(type))
         }
 
-    private fun revisionOf(type: Class<*>): String? =
-        revisionResolver.revisionOf(type)
-
     override fun getConverter(): Converter =
         converter
 
diff --git a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/serializer/ConfigTokenSerializer.kt b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/serializer/ConfigTokenSerializer.kt
new file mode 100644
index 00000000..2aa28289
--- /dev/null
+++ b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/serializer/ConfigTokenSerializer.kt
@@ -0,0 +1,49 @@
+package org.axonframework.extensions.kotlin.serialization.serializer
+
+import kotlinx.serialization.ExperimentalSerializationApi
+import kotlinx.serialization.KSerializer
+import kotlinx.serialization.SerializationException
+import kotlinx.serialization.Serializer
+import kotlinx.serialization.builtins.MapSerializer
+import kotlinx.serialization.builtins.serializer
+import kotlinx.serialization.descriptors.SerialDescriptor
+import kotlinx.serialization.descriptors.buildClassSerialDescriptor
+import kotlinx.serialization.descriptors.element
+import kotlinx.serialization.encoding.CompositeDecoder.Companion.DECODE_DONE
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.encoding.decodeStructure
+import kotlinx.serialization.encoding.encodeStructure
+import org.axonframework.eventhandling.tokenstore.ConfigToken
+
+@OptIn(ExperimentalSerializationApi::class)
+@Serializer(forClass = ConfigToken::class)
+class ConfigTokenSerializer : KSerializer<ConfigToken> {
+    override val descriptor: SerialDescriptor = buildClassSerialDescriptor("ConfigToken") {
+        element<Map<String, String>>("config")
+    }
+
+    override fun serialize(encoder: Encoder, value: ConfigToken) {
+        encoder.encodeStructure(descriptor) {
+            encodeSerializableElement(descriptor, 0, MapSerializer(String.serializer(), String.serializer()), value.config)
+        }
+    }
+
+    override fun deserialize(decoder: Decoder): ConfigToken {
+        return decoder.decodeStructure(descriptor) {
+            var config: Map<String, String>? = null
+
+            loop@ while (true) {
+                when (val index = decodeElementIndex(descriptor)) {
+                    DECODE_DONE -> break@loop
+
+                    0 -> config = decodeSerializableElement(descriptor, 0, MapSerializer(String.serializer(), String.serializer()))
+
+                    else -> throw SerializationException("Unexpected index $index")
+                }
+            }
+
+            ConfigToken(config)
+        }
+    }
+}
\ No newline at end of file
diff --git a/kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt b/kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt
index 1843acb9..7fce5a18 100644
--- a/kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt
+++ b/kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt
@@ -3,10 +3,15 @@ package org.axonframework.extensions.kotlin.serialization
 import kotlinx.serialization.Serializable
 import kotlinx.serialization.json.Json
 import kotlinx.serialization.json.JsonElement
+import kotlinx.serialization.modules.SerializersModule
+import kotlinx.serialization.modules.contextual
+import org.axonframework.eventhandling.tokenstore.ConfigToken
+import org.axonframework.extensions.kotlin.serialization.serializer.ConfigTokenSerializer
 import org.axonframework.serialization.AnnotationRevisionResolver
 import org.axonframework.serialization.ChainingConverter
 import org.axonframework.serialization.SerializedType
 import org.axonframework.serialization.SimpleSerializedObject
+import org.axonframework.serialization.UnknownSerializedType
 import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.Assertions.assertTrue
 import org.junit.jupiter.api.Test
@@ -65,31 +70,65 @@ class KotlinSerializerTest {
     fun deserialize() {
         val serializer = kotlinSerializer()
 
-        val nullDeserialized: Any? = serializer.deserialize(SimpleSerializedObject(
-            "",
-            String::class.java,
-            SerializedType.emptyType()
-        ))
+        val nullDeserialized: Any? = serializer.deserialize(
+            SimpleSerializedObject(
+                "",
+                String::class.java,
+                SerializedType.emptyType()
+            )
+        )
         assertNull(nullDeserialized)
 
-        val emptyDeserialized: Any? = serializer.deserialize(SimpleSerializedObject(
-            """{"name":"","value":null}""",
-            String::class.java,
-            TestData::class.java.name,
-            null
-        ))
+        val emptyDeserialized: Any? = serializer.deserialize(
+            SimpleSerializedObject(
+                """{"name":"","value":null}""",
+                String::class.java,
+                TestData::class.java.name,
+                null
+            )
+        )
         assertNotNull(emptyDeserialized as TestData)
         assertEquals(emptyDeserialized.name, "")
         assertEquals(emptyDeserialized.value, null)
 
-        val filledDeserialized: Any? = serializer.deserialize(SimpleSerializedObject(
-            """{"name":"name","value":1.23}""",
-            String::class.java,
-            TestData::class.java.name,
-            null
-        ))
+        val filledDeserialized: Any? = serializer.deserialize(
+            SimpleSerializedObject(
+                """{"name":"name","value":1.23}""",
+                String::class.java,
+                TestData::class.java.name,
+                null
+            )
+        )
         assertNotNull(filledDeserialized as TestData)
         assertEquals(filledDeserialized.name, "name")
         assertEquals(filledDeserialized.value, 1.23f)
+
+        val unknownDeserializedType: Any? = serializer.deserialize(
+            SimpleSerializedObject(
+                """anything""",
+                String::class.java,
+                UnknownSerializedType::class.java.name,
+                null
+            )
+        )
+        assertNotNull(unknownDeserializedType as UnknownSerializedType)
+    }
+
+    @Test
+    fun `example of custom serializer for ConfigToken`() {
+        val serializer = kotlinSerializer {
+            json = Json {
+                serializersModule = SerializersModule {
+                    contextual(ConfigTokenSerializer())
+                }
+            }
+        }
+
+        val tokenBefore = ConfigToken(mapOf("test" to "value"))
+        val serialized = serializer.serialize(tokenBefore, String::class.java)
+        assertEquals("""{"config":{"test":"value"}}""", serialized.data)
+        val token: ConfigToken? = serializer.deserialize(serialized)
+        assertNotNull(token as ConfigToken)
+        assertEquals("value", token.get("test"))
     }
 }
\ No newline at end of file

From edb6903e90cfe970ebadbdb0a768fbba906138dc Mon Sep 17 00:00:00 2001
From: Hidde Wieringa <hidde@hiddewieringa.nl>
Date: Thu, 3 Jun 2021 20:53:26 +0200
Subject: [PATCH 07/13] One more default

---
 .../extensions/kotlin/serialization/KotlinSerializer.kt         | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
index 085798a2..2624110c 100644
--- a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
+++ b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
@@ -54,7 +54,7 @@ import org.axonframework.serialization.SerializationException as AxonSerializati
 class KotlinSerializer(
     private val revisionResolver: RevisionResolver = AnnotationRevisionResolver(),
     private val converter: Converter = ChainingConverter(),
-    private val json: Json
+    private val json: Json = Json,
 ) : Serializer {
 
     private val serializerCache: MutableMap<Class<*>, KSerializer<*>> = mutableMapOf()

From b8fbd02805ac332b88aa302cfa741cd46929bfdd Mon Sep 17 00:00:00 2001
From: Hidde Wieringa <hidde@hiddewieringa.nl>
Date: Thu, 3 Jun 2021 21:09:11 +0200
Subject: [PATCH 08/13] Byte arrays

---
 .../kotlin/serialization/KotlinSerializer.kt           | 10 ++++++++++
 .../kotlin/serialization/KotlinSerializerTest.kt       |  7 +++++++
 2 files changed, 17 insertions(+)

diff --git a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
index 2624110c..cc98d0a7 100644
--- a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
+++ b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
@@ -70,6 +70,13 @@ class KotlinSerializer(
                         typeForClass(type)
                     )
 
+                expectedRepresentation.isAssignableFrom(ByteArray::class.java) ->
+                    SimpleSerializedObject(
+                        (if (value == null) ByteArray(0) else json.encodeToString(type.serializer(), value).toByteArray()) as T,
+                        expectedRepresentation,
+                        typeForClass(type)
+                    )
+
                 expectedRepresentation.isAssignableFrom(JsonElement::class.java) ->
                     SimpleSerializedObject(
                         (if (value == null) JsonNull else json.encodeToJsonElement(type.serializer(), value)) as T,
@@ -109,6 +116,9 @@ class KotlinSerializer(
                 serializedObject.contentType.isAssignableFrom(String::class.java) ->
                     json.decodeFromString(serializer, serializedObject.data as String)
 
+                serializedObject.contentType.isAssignableFrom(ByteArray::class.java) ->
+                    json.decodeFromString(serializer, (serializedObject.data as ByteArray).decodeToString())
+
                 serializedObject.contentType.isAssignableFrom(JsonElement::class.java) ->
                     json.decodeFromJsonElement(serializer, serializedObject.data as JsonElement)
 
diff --git a/kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt b/kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt
index 7fce5a18..19808710 100644
--- a/kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt
+++ b/kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt
@@ -114,6 +114,13 @@ class KotlinSerializerTest {
         assertNotNull(unknownDeserializedType as UnknownSerializedType)
     }
 
+    @Test
+    fun `byte arrays`() {
+        val serializer = kotlinSerializer()
+
+        assertNotNull(serializer.deserialize(serializer.serialize(TestData("name", null), ByteArray::class.java)))
+    }
+
     @Test
     fun `example of custom serializer for ConfigToken`() {
         val serializer = kotlinSerializer {

From c1130408230d387b2121dd2ecbc8ac593588be17 Mon Sep 17 00:00:00 2001
From: Hidde Wieringa <hidde@hiddewieringa.nl>
Date: Thu, 3 Jun 2021 21:41:29 +0200
Subject: [PATCH 09/13] Use chaining converters, add tests for input stream,
 JSON elements and byte arrays

---
 .../kotlin/serialization/KotlinSerializer.kt  | 60 +++++++------------
 .../serialization/KotlinSerializerTest.kt     | 17 ++++++
 2 files changed, 40 insertions(+), 37 deletions(-)

diff --git a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
index cc98d0a7..338d3402 100644
--- a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
+++ b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
@@ -62,39 +62,31 @@ class KotlinSerializer(
     override fun <T> serialize(value: Any?, expectedRepresentation: Class<T>): SerializedObject<T> {
         try {
             val type = ObjectUtils.nullSafeTypeOf(value)
-            return when {
-                expectedRepresentation.isAssignableFrom(String::class.java) ->
-                    SimpleSerializedObject(
-                        (if (value == null) "null" else json.encodeToString(type.serializer(), value)) as T,
-                        expectedRepresentation,
-                        typeForClass(type)
-                    )
-
-                expectedRepresentation.isAssignableFrom(ByteArray::class.java) ->
-                    SimpleSerializedObject(
-                        (if (value == null) ByteArray(0) else json.encodeToString(type.serializer(), value).toByteArray()) as T,
-                        expectedRepresentation,
-                        typeForClass(type)
-                    )
-
-                expectedRepresentation.isAssignableFrom(JsonElement::class.java) ->
-                    SimpleSerializedObject(
-                        (if (value == null) JsonNull else json.encodeToJsonElement(type.serializer(), value)) as T,
-                        expectedRepresentation,
-                        typeForClass(type)
-                    )
-
-                else ->
-                    throw AxonSerializationException("Cannot serialize type $type to representation $expectedRepresentation. String and JsonElement are supported.")
+
+            if (expectedRepresentation.isAssignableFrom(JsonElement::class.java)) {
+                return SimpleSerializedObject(
+                    (if (value == null) JsonNull else json.encodeToJsonElement(type.serializer(), value)) as T,
+                    expectedRepresentation,
+                    typeForClass(type)
+                )
             }
+
+            // By default, encode to String. This can be converted to other types by the converter
+            val stringSerialized: SerializedObject<String> = SimpleSerializedObject(
+                (if (value == null) "null" else json.encodeToString(type.serializer(), value)),
+                String::class.java,
+                typeForClass(type)
+            )
+
+            return converter.convert(stringSerialized, expectedRepresentation)
         } catch (ex: SerializationException) {
             throw AxonSerializationException("Cannot serialize type ${value?.javaClass?.name} to representation $expectedRepresentation.", ex)
         }
     }
 
     override fun <T> canSerializeTo(expectedRepresentation: Class<T>): Boolean =
-        expectedRepresentation == String::class.java ||
-                expectedRepresentation == JsonElement::class.java
+        expectedRepresentation == JsonElement::class.java ||
+                converter.canConvert(String::class.java, expectedRepresentation)
 
     override fun <S, T> deserialize(serializedObject: SerializedObject<S>?): T? {
         try {
@@ -112,19 +104,13 @@ class KotlinSerializer(
             }
 
             val serializer: KSerializer<T> = foundType.serializer() as KSerializer<T>
-            return when {
-                serializedObject.contentType.isAssignableFrom(String::class.java) ->
-                    json.decodeFromString(serializer, serializedObject.data as String)
 
-                serializedObject.contentType.isAssignableFrom(ByteArray::class.java) ->
-                    json.decodeFromString(serializer, (serializedObject.data as ByteArray).decodeToString())
-
-                serializedObject.contentType.isAssignableFrom(JsonElement::class.java) ->
-                    json.decodeFromJsonElement(serializer, serializedObject.data as JsonElement)
-
-                else ->
-                    throw AxonSerializationException("Cannot deserialize from content type ${serializedObject.contentType} to type ${serializedObject.type}. String and JsonElement are supported.")
+            if (serializedObject.contentType.isAssignableFrom(JsonElement::class.java)) {
+                return json.decodeFromJsonElement(serializer, serializedObject.data as JsonElement)
             }
+
+            val stringSerialized: SerializedObject<String> = converter.convert(serializedObject, String::class.java)
+            return json.decodeFromString(serializer, stringSerialized.data)
         } catch (ex: SerializationException) {
             throw AxonSerializationException(
                 "Could not deserialize from content type ${serializedObject?.contentType} to type ${serializedObject?.type}",
diff --git a/kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt b/kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt
index 19808710..7b2430c3 100644
--- a/kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt
+++ b/kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt
@@ -15,6 +15,7 @@ import org.axonframework.serialization.UnknownSerializedType
 import org.junit.jupiter.api.Assertions.assertEquals
 import org.junit.jupiter.api.Assertions.assertTrue
 import org.junit.jupiter.api.Test
+import java.io.InputStream
 import kotlin.test.assertNotNull
 import kotlin.test.assertNull
 
@@ -34,7 +35,9 @@ class KotlinSerializerTest {
         val serializer = kotlinSerializer()
 
         assertTrue(serializer.canSerializeTo(String::class.java))
+        assertTrue(serializer.canSerializeTo(ByteArray::class.java))
         assertTrue(serializer.canSerializeTo(JsonElement::class.java))
+        assertTrue(serializer.canSerializeTo(InputStream::class.java))
     }
 
     @Test
@@ -121,6 +124,20 @@ class KotlinSerializerTest {
         assertNotNull(serializer.deserialize(serializer.serialize(TestData("name", null), ByteArray::class.java)))
     }
 
+    @Test
+    fun `JSON elements`() {
+        val serializer = kotlinSerializer()
+
+        assertNotNull(serializer.deserialize(serializer.serialize(TestData("name", null), JsonElement::class.java)))
+    }
+
+    @Test
+    fun `input stream`() {
+        val serializer = kotlinSerializer()
+
+        assertNotNull(serializer.deserialize(serializer.serialize(TestData("name", null), InputStream::class.java)))
+    }
+
     @Test
     fun `example of custom serializer for ConfigToken`() {
         val serializer = kotlinSerializer {

From 7acce4cc01da52414950d353a80a1917573ed1a0 Mon Sep 17 00:00:00 2001
From: Hidde Wieringa <hidde@hiddewieringa.nl>
Date: Mon, 20 Sep 2021 20:50:55 +0200
Subject: [PATCH 10/13] Remove the configuration DSL class

---
 .../kotlin/serialization/KotlinSerializer.kt  | 37 -------------------
 .../serialization/KotlinSerializerTest.kt     | 27 +++++++-------
 2 files changed, 14 insertions(+), 50 deletions(-)

diff --git a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
index 338d3402..87f63914 100644
--- a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
+++ b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
@@ -172,41 +172,4 @@ class KotlinSerializer(
     override fun getConverter(): Converter =
         converter
 
-}
-
-/**
- * Configuration which will be used to construct a KotlinSerializer.
- * This class is used in the kotlinSerializer DSL function.
- *
- * @see KotlinSerializer
- * @see kotlinSerializer
- */
-class KotlinSerializerConfiguration {
-    var revisionResolver: RevisionResolver = AnnotationRevisionResolver()
-    var converter: Converter = ChainingConverter()
-    var json: Json = Json
-}
-
-/**
- * DSL function to configure a new KotlinSerializer.
- *
- * Usage example:
- * <code>
- *     val serializer: KotlinSerializer = kotlinSerializer {
- *          json = Json
- *          converter = ChainingConverter()
- *          revisionResolver = AnnotationRevisionResolver()
- *     }
- * </code>
- *
- * @see KotlinSerializer
- */
-fun kotlinSerializer(init: KotlinSerializerConfiguration.() -> Unit = {}): KotlinSerializer {
-    val configuration = KotlinSerializerConfiguration()
-    configuration.init()
-    return KotlinSerializer(
-        configuration.revisionResolver,
-        configuration.converter,
-        configuration.json,
-    )
 }
\ No newline at end of file
diff --git a/kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt b/kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt
index 7b2430c3..15bc7448 100644
--- a/kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt
+++ b/kotlin/src/test/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializerTest.kt
@@ -32,7 +32,7 @@ class KotlinSerializerTest {
 
     @Test
     fun canSerializeTo() {
-        val serializer = kotlinSerializer()
+        val serializer = KotlinSerializer()
 
         assertTrue(serializer.canSerializeTo(String::class.java))
         assertTrue(serializer.canSerializeTo(ByteArray::class.java))
@@ -42,17 +42,18 @@ class KotlinSerializerTest {
 
     @Test
     fun `configuration options`() {
-        val serializer = kotlinSerializer {
-            json = Json
-            converter = ChainingConverter()
-            revisionResolver = AnnotationRevisionResolver()
-        }
+        val serializer = KotlinSerializer(
+            revisionResolver = AnnotationRevisionResolver(),
+            converter = ChainingConverter(),
+            json = Json,
+        )
+
         assertNotNull(serializer)
     }
 
     @Test
     fun serialize() {
-        val serializer = kotlinSerializer()
+        val serializer = KotlinSerializer()
 
         val emptySerialized = serializer.serialize(TestData("", null), String::class.java)
         assertEquals("SimpleSerializedType[org.axonframework.extensions.kotlin.serialization.KotlinSerializerTest\$TestData] (revision null)", emptySerialized.type.toString())
@@ -71,7 +72,7 @@ class KotlinSerializerTest {
 
     @Test
     fun deserialize() {
-        val serializer = kotlinSerializer()
+        val serializer = KotlinSerializer()
 
         val nullDeserialized: Any? = serializer.deserialize(
             SimpleSerializedObject(
@@ -119,34 +120,34 @@ class KotlinSerializerTest {
 
     @Test
     fun `byte arrays`() {
-        val serializer = kotlinSerializer()
+        val serializer = KotlinSerializer()
 
         assertNotNull(serializer.deserialize(serializer.serialize(TestData("name", null), ByteArray::class.java)))
     }
 
     @Test
     fun `JSON elements`() {
-        val serializer = kotlinSerializer()
+        val serializer = KotlinSerializer()
 
         assertNotNull(serializer.deserialize(serializer.serialize(TestData("name", null), JsonElement::class.java)))
     }
 
     @Test
     fun `input stream`() {
-        val serializer = kotlinSerializer()
+        val serializer = KotlinSerializer()
 
         assertNotNull(serializer.deserialize(serializer.serialize(TestData("name", null), InputStream::class.java)))
     }
 
     @Test
     fun `example of custom serializer for ConfigToken`() {
-        val serializer = kotlinSerializer {
+        val serializer = KotlinSerializer(
             json = Json {
                 serializersModule = SerializersModule {
                     contextual(ConfigTokenSerializer())
                 }
             }
-        }
+        )
 
         val tokenBefore = ConfigToken(mapOf("test" to "value"))
         val serialized = serializer.serialize(tokenBefore, String::class.java)

From e0f411ac1c60db714809cc0075c502e67d144bac Mon Sep 17 00:00:00 2001
From: Hidde Wieringa <hidde@hiddewieringa.nl>
Date: Sat, 16 Apr 2022 13:25:23 +0200
Subject: [PATCH 11/13] Kotlin serialization 1.3.2

---
 pom.xml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/pom.xml b/pom.xml
index febf81ad..ea7e6ece 100644
--- a/pom.xml
+++ b/pom.xml
@@ -36,7 +36,7 @@
     <kotlin.version>1.6.20</kotlin.version>
     <jackson-kotlin.version>2.13.2</jackson-kotlin.version>
     <kotlin-logging.version>2.1.21</kotlin-logging.version>
-    <kotlin-serialization.version>1.2.1</kotlin-serialization.version>
+    <kotlin-serialization.version>1.3.2</kotlin-serialization.version>
     <mockk.version>1.12.3</mockk.version>
     <junit.jupiter.version>5.8.2</junit.jupiter.version>
     <slf4j.version>1.7.36</slf4j.version>

From 8d7b70d7c1407917b5d7e185cfb7d2f8dcc255b4 Mon Sep 17 00:00:00 2001
From: Hidde Wieringa <hidde@hiddewieringa.nl>
Date: Sat, 16 Apr 2022 13:38:06 +0200
Subject: [PATCH 12/13] better check for JsonElement assignability

---
 .../extensions/kotlin/serialization/KotlinSerializer.kt         | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
index 87f63914..2c3eb4fc 100644
--- a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
+++ b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/KotlinSerializer.kt
@@ -85,7 +85,7 @@ class KotlinSerializer(
     }
 
     override fun <T> canSerializeTo(expectedRepresentation: Class<T>): Boolean =
-        expectedRepresentation == JsonElement::class.java ||
+        expectedRepresentation.isAssignableFrom(JsonElement::class.java) ||
                 converter.canConvert(String::class.java, expectedRepresentation)
 
     override fun <S, T> deserialize(serializedObject: SerializedObject<S>?): T? {

From 34844c8f27034764c14e2c0ac962837e3fb1dd05 Mon Sep 17 00:00:00 2001
From: Hidde Wieringa <hidde@hiddewieringa.nl>
Date: Sat, 16 Apr 2022 14:39:51 +0200
Subject: [PATCH 13/13] Use surrogate in example. `@Serializer(forClass = ...)`
 still doesnt work

---
 .../serializer/ConfigTokenSerializer.kt       | 61 ++++++++-----------
 1 file changed, 25 insertions(+), 36 deletions(-)

diff --git a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/serializer/ConfigTokenSerializer.kt b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/serializer/ConfigTokenSerializer.kt
index 2aa28289..f923d420 100644
--- a/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/serializer/ConfigTokenSerializer.kt
+++ b/kotlin/src/main/kotlin/org/axonframework/extensions/kotlin/serialization/serializer/ConfigTokenSerializer.kt
@@ -2,48 +2,37 @@ package org.axonframework.extensions.kotlin.serialization.serializer
 
 import kotlinx.serialization.ExperimentalSerializationApi
 import kotlinx.serialization.KSerializer
-import kotlinx.serialization.SerializationException
+import kotlinx.serialization.Serializable
 import kotlinx.serialization.Serializer
-import kotlinx.serialization.builtins.MapSerializer
-import kotlinx.serialization.builtins.serializer
 import kotlinx.serialization.descriptors.SerialDescriptor
-import kotlinx.serialization.descriptors.buildClassSerialDescriptor
-import kotlinx.serialization.descriptors.element
-import kotlinx.serialization.encoding.CompositeDecoder.Companion.DECODE_DONE
 import kotlinx.serialization.encoding.Decoder
 import kotlinx.serialization.encoding.Encoder
-import kotlinx.serialization.encoding.decodeStructure
-import kotlinx.serialization.encoding.encodeStructure
 import org.axonframework.eventhandling.tokenstore.ConfigToken
 
+@Serializable
+data class ConfigTokenSurrogate(
+    private val config: Map<String, String>
+) {
+    fun toToken() = ConfigToken(config)
+}
+
+fun ConfigToken.toSurrogate() = ConfigTokenSurrogate(config)
+
 @OptIn(ExperimentalSerializationApi::class)
 @Serializer(forClass = ConfigToken::class)
 class ConfigTokenSerializer : KSerializer<ConfigToken> {
-    override val descriptor: SerialDescriptor = buildClassSerialDescriptor("ConfigToken") {
-        element<Map<String, String>>("config")
-    }
-
-    override fun serialize(encoder: Encoder, value: ConfigToken) {
-        encoder.encodeStructure(descriptor) {
-            encodeSerializableElement(descriptor, 0, MapSerializer(String.serializer(), String.serializer()), value.config)
-        }
-    }
-
-    override fun deserialize(decoder: Decoder): ConfigToken {
-        return decoder.decodeStructure(descriptor) {
-            var config: Map<String, String>? = null
-
-            loop@ while (true) {
-                when (val index = decodeElementIndex(descriptor)) {
-                    DECODE_DONE -> break@loop
-
-                    0 -> config = decodeSerializableElement(descriptor, 0, MapSerializer(String.serializer(), String.serializer()))
-
-                    else -> throw SerializationException("Unexpected index $index")
-                }
-            }
-
-            ConfigToken(config)
-        }
-    }
-}
\ No newline at end of file
+    override val descriptor: SerialDescriptor = ConfigTokenSurrogate.serializer().descriptor
+
+    override fun serialize(encoder: Encoder, value: ConfigToken) =
+        encoder.encodeSerializableValue(ConfigTokenSurrogate.serializer(), value.toSurrogate())
+
+    override fun deserialize(decoder: Decoder): ConfigToken =
+        decoder.decodeSerializableValue(ConfigTokenSurrogate.serializer()).toToken()
+}
+
+// The following does not work, emits compiler errors.
+// Also with the `-Xuse-ir` Kotlin compiler argument (version 1.6.20)
+
+//@OptIn(ExperimentalSerializationApi::class)
+//@Serializer(forClass = ConfigToken::class)
+//object ConfigTokenSerializer
\ No newline at end of file