One of support for lagom

generated/src/main/scala/api/AppleReqDisc.scala

@@ -0,0 +1,24 @@
+/**
+ * fruity
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ *
+ * The version of the OpenAPI document: 0.0.1
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+package api
+import play.api.libs.json._
+
+            final case class AppleReqDisc extends Fruit (
+                seeds: Int,
+        )
+
+            object AppleReqDisc {
+                implicit val format: Format[AppleReqDisc] = Json.format
+            }
+
+

generated/src/main/scala/api/BananaReqDisc.scala

@@ -0,0 +1,24 @@
+/**
+ * fruity
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ *
+ * The version of the OpenAPI document: 0.0.1
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+package api
+import play.api.libs.json._
+
+            final case class BananaReqDisc extends Fruit (
+                length: Int,
+        )
+
+            object BananaReqDisc {
+                implicit val format: Format[BananaReqDisc] = Json.format
+            }
+
+

generated/src/main/scala/api/Fruit.scala

@@ -0,0 +1,39 @@
+/**
+ * fruity
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ *
+ * The version of the OpenAPI document: 0.0.1
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+package api
+import play.api.libs.json._
+
+            trait Fruit (
+                fruitType: String,
+        )
+
+            object Fruit {
+                private val discriminator = "fruitType"
+
+                implicit val format: OFormat[Fruit] = new OFormat[Fruit]{
+                    override def reads(json: JsValue): JsResult[Fruit] =
+                        json.validate[JsObject].flatMap(
+                            _.value(discriminator).as[String] match {
+                                case "AppleReqDisc" => json.validate[AppleReqDisc]
+                                case "BananaReqDisc" => json.validate[BananaReqDisc]
+                            }
+                        )
+
+                    override def writes(o: Fruit): JsObject = o match {
+                            case a: AppleReqDisc => AppleReqDisc.format.writes(a) + (discriminator -> JsString("AppleReqDisc"))
+                            case a: BananaReqDisc => BananaReqDisc.format.writes(a) + (discriminator -> JsString("BananaReqDisc"))
+                    }
+                }
+            }
+
+

generated/src/main/scala/api/FruitBasket.scala

@@ -0,0 +1,25 @@
+/**
+ * fruity
+ * No description provided (generated by Openapi Generator https://github.com/openapitools/openapi-generator)
+ *
+ * The version of the OpenAPI document: 0.0.1
+ * 
+ *
+ * NOTE: This class is auto generated by OpenAPI Generator (https://openapi-generator.tech).
+ * https://openapi-generator.tech
+ * Do not edit the class manually.
+ */
+
+package api
+import play.api.libs.json._
+
+            final case class FruitBasket   (
+                quantity: Option[Int],
+                fruit: Option[Fruit]
+        )
+
+            object FruitBasket {
+                implicit val format: Format[FruitBasket] = Json.format
+            }
+
+

modules/openapi-generator/src/main/java/org/openapitools/codegen/languages/ScalaLagomServerCodegen.java

@@ -24,6 +24,7 @@
 import org.slf4j.LoggerFactory;
 
 import java.util.*;
+import java.util.stream.Collectors;
 
 import static org.openapitools.codegen.utils.StringUtils.camelize;
 import static org.openapitools.codegen.utils.StringUtils.underscore;
@@ -163,6 +164,42 @@ public String toOperationId(String operationId) {
         return camelize(operationId, true);
     }
 
+    private CodegenModel codegenModel(Object o) {
+        return ((Map<String, List<Map<String, CodegenModel>>>)o).get("models").get(0).get("model");
+    }
+
+    @Override
+    public Map<String, Object> postProcessAllModels(final Map<String, Object> objs) {
+
+        for(Object value : objs.values()) {
+            if(value instanceof Map) {
+                CodegenModel m = codegenModel(value);
+                // for oneOf schemas
+                if(!m.oneOf.isEmpty() && m.getDiscriminator() != null) {
+                    // add it as a parent to every single model and removed unnecessary discriminator prop
+                    m.oneOf.forEach(
+                        subclassName -> {
+                            CodegenModel cm = codegenModel(objs.get(subclassName));
+                            cm.setParent(m.classname);
+                            if(!cm.getVars().isEmpty()) {
+                                cm.setVars(
+                                    cm.getVars().stream().filter(v -> !v.getName().equals(m.getDiscriminator().getPropertyName())).collect(Collectors.toList())
+                                );
+                            }
+                        }
+                    );
+                    // retain only discriminator prop
+                    if(!m.getVars().isEmpty()) {
+                        m.setVars(
+                                m.getVars().stream().filter(v -> v.getName().equals(m.getDiscriminator().getPropertyName())).collect(Collectors.toList())
+                        );
+                    }
+                }
+            }
+        }
+        return objs;
+    }
+
     @Override
     public Map<String, Object> postProcessModelsEnum(Map<String, Object> objs) {
         objs = super.postProcessModelsEnum(objs);

modules/openapi-generator/src/main/resources/scala-lagom-server/model.mustache

@@ -7,32 +7,66 @@ import {{import}}
 
 {{#models}}
 {{#model}}
-case class {{classname}} (
-{{#vars}}
     {{#isEnum}}
-                  {{{name}}}:  Option[{{classname}}{{datatypeWithEnum}}.{{classname}}{{datatypeWithEnum}}]{{#hasMore}},{{/hasMore}}
+        {{classname}}{{datatypeWithEnum}} extends Enumeration {
+        val {{#allowableValues}}  {{#values}}{{.}}{{^-last}}, {{/-last}}{{/values}} = Value{{/allowableValues}}
+        type {{classname}}{{datatypeWithEnum}} = Value
+        implicit val format: Format[Value] = Format(Reads.enumNameReads(this), Writes.enumNameWrites[{{classname}}{{datatypeWithEnum}}.type])
+        }
     {{/isEnum}}
     {{^isEnum}}
-        {{#description}}
-            /* {{{description}}} */
-        {{/description}}
-                  {{{name}}}: {{^required}}Option[{{/required}}{{dataType}}{{^required}}]{{/required}}{{#hasMore}},{{/hasMore}}
-    {{/isEnum}}
-{{/vars}}
-)
+        {{#discriminator}}
+            trait {{classname}} (
+        {{/discriminator}}
+        {{^discriminator}}
+            final case class {{classname}} {{#parent}}extends{{/parent}} {{parent}} (
+        {{/discriminator}}
+        {{#vars}}
+            {{#isEnum}}
+                {{{name}}}:  Option[{{classname}}{{datatypeWithEnum}}.{{classname}}{{datatypeWithEnum}}]{{#hasMore}},{{/hasMore}}
+            {{/isEnum}}
+            {{^isEnum}}
+                {{#description}}
+                    /* {{{description}}} */
+                {{/description}}
+                {{{name}}}: {{^required}}Option[{{/required}}{{dataType}}{{^required}}]{{/required}}{{#hasMore}},{{/hasMore}}
+            {{/isEnum}}
+        {{/vars}}
+        )
+
+            object {{classname}} {
+            {{#discriminator}}
+                private val discriminator = "{{discriminator.propertyBaseName}}"
+
+                implicit val format: OFormat[{{classname}}] = new OFormat[Fruit]{
+                    override def reads(json: JsValue): JsResult[{{classname}}] =
+                        json.validate[JsObject].flatMap(
+                            _.value(discriminator).as[String] match {
+                                {{#oneOf}}
+                                case "{{.}}" => json.validate[{{.}}]
+                                {{/oneOf}}
+                            }
+                        )
 
-object {{classname}} {
-implicit val format: Format[{{classname}}] = Json.format
-}
+                    override def writes(o: {{classname}}): JsObject = o match {
+                        {{#oneOf}}
+                            case a: {{.}} => {{.}}.format.writes(a) + (discriminator -> JsString("{{.}}"))
+                        {{/oneOf}}
+                    }
+                }
+            {{/discriminator}}
+            {{^discriminator}}
+                implicit val format: Format[{{classname}}] = Json.format
+            {{/discriminator}}
+            }
 
-{{#vars}}
-  {{#isEnum}}
-object {{classname}}{{datatypeWithEnum}} extends Enumeration {
-  val {{#allowableValues}}  {{#values}}{{.}}{{^-last}}, {{/-last}}{{/values}} = Value{{/allowableValues}}
-  type {{classname}}{{datatypeWithEnum}} = Value
-  implicit val format: Format[Value] = Format(Reads.enumNameReads(this), Writes.enumNameWrites[{{classname}}{{datatypeWithEnum}}.type])
-}
- {{/isEnum}}
-{{/vars}}
+        {{#vars}}
+            {{#isEnum}}
+                object {{classname}}{{datatypeWithEnum}} extends Enumeration {
+                }
+            {{/isEnum}}
+        {{/vars}}
+
+    {{/isEnum}}
 {{/model}}
-{{/models}}
+{{/models}}

modules/openapi-generator/src/test/resources/3_0/oneoOfDiscriminatorSimple.yaml

@@ -0,0 +1,48 @@
+openapi: 3.0.1
+info:
+  title: fruity
+  version: 0.0.1
+paths:
+  /:
+    get:
+      responses:
+        '200':
+          description: desc
+          content:
+            application/json:
+              schema:
+                $ref: '#/components/schemas/FruitBasket'
+components:
+  schemas:
+    FruitBasket:
+      properties:
+        quantity:
+          type: int
+        fruit:
+          $ref: '#/components/schemas/Fruit'
+    Fruit:
+      oneOf:
+        - $ref: '#/components/schemas/AppleReqDisc'
+        - $ref: '#/components/schemas/BananaReqDisc'
+      discriminator:
+        propertyName: fruitType
+    AppleReqDisc:
+      type: object
+      required:
+        - seeds
+        - fruitType
+      properties:
+        seeds:
+          type: integer
+        fruitType:
+          type: string
+    BananaReqDisc:
+      type: object
+      required:
+        - length
+        - fruitType
+      properties:
+        length:
+          type: integer
+        fruitType:
+          type: string