(feat) Polymorphism support for kotlinx serialization

Fixes #707. Adds basic polymorphism support to Kotlinx serialization
springwolf · Apr 20, 2024 · a9d4e1f · a9d4e1f
1 parent a3198a4
commit a9d4e1f
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Showing 3 changed files with 50 additions and 4 deletions.
diff --git a/...ons/kotlinx_serialization_model_converter/converter/KotlinxSerializationModelConverter.kt b/...ons/kotlinx_serialization_model_converter/converter/KotlinxSerializationModelConverter.kt
@@ -5,6 +5,7 @@ import io.swagger.v3.core.converter.ModelConverter
 import io.swagger.v3.core.converter.ModelConverterContext
 import io.swagger.v3.core.util.RefUtils
 import io.swagger.v3.oas.models.media.ArraySchema
+import io.swagger.v3.oas.models.media.ComposedSchema
 import io.swagger.v3.oas.models.media.MapSchema
 import io.swagger.v3.oas.models.media.ObjectSchema
 import io.swagger.v3.oas.models.media.Schema
@@ -60,12 +61,18 @@ class KotlinxSerializationModelConverter(private val useFqn: Boolean = false) :
 
     private fun getPropertySchema(property: KProperty1<*, *>, context: ModelConverterContext): Schema<*> {
         val propertySchema: Schema<*>
-
-       val name = getPropertyName(property)
-
+        val name = getPropertyName(property)
         val propertyType = property.returnType.jvmErasure
 
         when {
+            propertyType.sealedSubclasses.isNotEmpty() -> {
+                propertySchema = ComposedSchema()
+                propertyType.sealedSubclasses.forEach { subClass ->
+                    val subSchema = resolveRefSchema(subClass.java, context)
+                    propertySchema.addOneOfItem(subSchema)
+                }
+            }
+
             propertyType.isSubclassOf(Collection::class) -> {
                 propertySchema = ArraySchema()
                 val value = (property.returnType.javaType as ParameterizedType).actualTypeArguments[0]

diff --git a/...otlinx_serialization_model_converter/converter/KotlinxSerializationTypeConverterTest.java b/...otlinx_serialization_model_converter/converter/KotlinxSerializationTypeConverterTest.java
@@ -137,6 +137,28 @@ void testClassWithNestedProperty() {
         }
     }
 
+    @Nested
+    class TestSealedClass {
+        @Test
+        void testSealedClassSerialization() {
+            var result = modelConverters.readAll(new AnnotatedType(ClassWithPolymorphism.class));
+            assertThat(result).hasSize(3);
+            assertThat(result.get(Dog.class.getSimpleName())).isNotNull();
+            assertThat(result.get(Cat.class.getSimpleName())).isNotNull();
+            assertThat(result.get(Pet.class.getSimpleName())).isNull();
+
+            Schema<?> schema = result.get(ClassWithPolymorphism.class.getSimpleName());
+
+            final Schema<?> sealedClass = (Schema<?>) schema.getProperties().get("pet");
+            assertThat(sealedClass).isNotNull();
+            assertThat(sealedClass.getType()).isNull();
+            assertThat(sealedClass.get$ref()).isNull();
+            assertThat(sealedClass.getOneOf()).hasSize(2);
+            assertThat(sealedClass.getOneOf().get(0).get$ref()).isEqualTo("#/components/schemas/Cat");
+            assertThat(sealedClass.getOneOf().get(1).get$ref()).isEqualTo("#/components/schemas/Dog");
+        }
+    }
+
     @Test
     void serializeKotlin() {
         final KotlinxSerializationModelConverter modelConverter = new KotlinxSerializationModelConverter();

diff --git a/...o.github.springwolf.addons.kotlinx_serialization_model_converter.converter/SampleEvent.kt b/...o.github.springwolf.addons.kotlinx_serialization_model_converter.converter/SampleEvent.kt
@@ -89,4 +89,21 @@ data class ClassWithNestedProperty(
         val name: String,
         val color: Color,
     )
-}
+}
+
+@Serializable
+data class ClassWithPolymorphism(
+    @SerialName("pet")
+    val pet: Pet,
+)
+
+@Serializable
+sealed interface Pet
+
+@Serializable
+@SerialName("dog")
+data class Dog(val bark: Boolean, val breed: String) : Pet
+
+@Serializable
+@SerialName("cat")
+data class Cat(val hunt: Boolean, val age: Int): Pet