[java][okhttp-gson-nextgen] Better null handling in oneOf, anyOf model (#11056)

* better null handling in oneOf model

* update anyof with better null handling

* add null test

modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson-nextgen/anyof_model.mustache

@@ -50,6 +50,11 @@ public class {{classname}} extends AbstractOpenApiSchema{{#vendorExtensions.x-im
             return (TypeAdapter<T>) new TypeAdapter<{{classname}}>() {
                 @Override
                 public void write(JsonWriter out, {{classname}} value) throws IOException {
+                    if (value == null || value.getActualInstance() == null) {
+                        elementAdapter.write(out, null);
+                        return;
+                    }
+
                     {{#anyOf}}
                     // check if the actual instance is of the type `{{.}}`
                     if (value.getActualInstance() instanceof {{.}}) {

modules/openapi-generator/src/main/resources/Java/libraries/okhttp-gson-nextgen/oneof_model.mustache

@@ -50,6 +50,11 @@ public class {{classname}} extends AbstractOpenApiSchema{{#vendorExtensions.x-im
             return (TypeAdapter<T>) new TypeAdapter<{{classname}}>() {
                 @Override
                 public void write(JsonWriter out, {{classname}} value) throws IOException {
+                    if (value == null || value.getActualInstance() == null) {
+                        elementAdapter.write(out, null);
+                        return;
+                    }
+
                     {{#oneOf}}
                     // check if the actual instance is of the type `{{.}}`
                     if (value.getActualInstance() instanceof {{.}}) {

samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/model/Fruit.java

@@ -78,6 +78,11 @@ public class Fruit extends AbstractOpenApiSchema {
             return (TypeAdapter<T>) new TypeAdapter<Fruit>() {
                 @Override
                 public void write(JsonWriter out, Fruit value) throws IOException {
+                    if (value == null || value.getActualInstance() == null) {
+                        elementAdapter.write(out, null);
+                        return;
+                    }
+
                     // check if the actual instance is of the type `Apple`
                     if (value.getActualInstance() instanceof Apple) {
                         JsonObject obj = adapterApple.toJsonTree((Apple)value.getActualInstance()).getAsJsonObject();

samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/model/FruitReq.java

@@ -78,6 +78,11 @@ public class FruitReq extends AbstractOpenApiSchema {
             return (TypeAdapter<T>) new TypeAdapter<FruitReq>() {
                 @Override
                 public void write(JsonWriter out, FruitReq value) throws IOException {
+                    if (value == null || value.getActualInstance() == null) {
+                        elementAdapter.write(out, null);
+                        return;
+                    }
+
                     // check if the actual instance is of the type `AppleReq`
                     if (value.getActualInstance() instanceof AppleReq) {
                         JsonObject obj = adapterAppleReq.toJsonTree((AppleReq)value.getActualInstance()).getAsJsonObject();

samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/model/GmFruit.java

@@ -78,6 +78,11 @@ public class GmFruit extends AbstractOpenApiSchema {
             return (TypeAdapter<T>) new TypeAdapter<GmFruit>() {
                 @Override
                 public void write(JsonWriter out, GmFruit value) throws IOException {
+                    if (value == null || value.getActualInstance() == null) {
+                        elementAdapter.write(out, null);
+                        return;
+                    }
+
                     // check if the actual instance is of the type `Apple`
                     if (value.getActualInstance() instanceof Apple) {
                         JsonObject obj = adapterApple.toJsonTree((Apple)value.getActualInstance()).getAsJsonObject();

samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/model/Mammal.java

@@ -79,6 +79,11 @@ public class Mammal extends AbstractOpenApiSchema {
             return (TypeAdapter<T>) new TypeAdapter<Mammal>() {
                 @Override
                 public void write(JsonWriter out, Mammal value) throws IOException {
+                    if (value == null || value.getActualInstance() == null) {
+                        elementAdapter.write(out, null);
+                        return;
+                    }
+
                     // check if the actual instance is of the type `Pig`
                     if (value.getActualInstance() instanceof Pig) {
                         JsonObject obj = adapterPig.toJsonTree((Pig)value.getActualInstance()).getAsJsonObject();

samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/model/NullableShape.java

@@ -77,6 +77,11 @@ public class NullableShape extends AbstractOpenApiSchema {
             return (TypeAdapter<T>) new TypeAdapter<NullableShape>() {
                 @Override
                 public void write(JsonWriter out, NullableShape value) throws IOException {
+                    if (value == null || value.getActualInstance() == null) {
+                        elementAdapter.write(out, null);
+                        return;
+                    }
+
                     // check if the actual instance is of the type `Quadrilateral`
                     if (value.getActualInstance() instanceof Quadrilateral) {
                         JsonObject obj = adapterQuadrilateral.toJsonTree((Quadrilateral)value.getActualInstance()).getAsJsonObject();

samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/model/Pig.java

@@ -77,6 +77,11 @@ public class Pig extends AbstractOpenApiSchema {
             return (TypeAdapter<T>) new TypeAdapter<Pig>() {
                 @Override
                 public void write(JsonWriter out, Pig value) throws IOException {
+                    if (value == null || value.getActualInstance() == null) {
+                        elementAdapter.write(out, null);
+                        return;
+                    }
+
                     // check if the actual instance is of the type `BasquePig`
                     if (value.getActualInstance() instanceof BasquePig) {
                         JsonObject obj = adapterBasquePig.toJsonTree((BasquePig)value.getActualInstance()).getAsJsonObject();

samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/model/Quadrilateral.java

@@ -77,6 +77,11 @@ public class Quadrilateral extends AbstractOpenApiSchema {
             return (TypeAdapter<T>) new TypeAdapter<Quadrilateral>() {
                 @Override
                 public void write(JsonWriter out, Quadrilateral value) throws IOException {
+                    if (value == null || value.getActualInstance() == null) {
+                        elementAdapter.write(out, null);
+                        return;
+                    }
+
                     // check if the actual instance is of the type `ComplexQuadrilateral`
                     if (value.getActualInstance() instanceof ComplexQuadrilateral) {
                         JsonObject obj = adapterComplexQuadrilateral.toJsonTree((ComplexQuadrilateral)value.getActualInstance()).getAsJsonObject();

samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/model/Shape.java

@@ -77,6 +77,11 @@ public class Shape extends AbstractOpenApiSchema {
             return (TypeAdapter<T>) new TypeAdapter<Shape>() {
                 @Override
                 public void write(JsonWriter out, Shape value) throws IOException {
+                    if (value == null || value.getActualInstance() == null) {
+                        elementAdapter.write(out, null);
+                        return;
+                    }
+
                     // check if the actual instance is of the type `Quadrilateral`
                     if (value.getActualInstance() instanceof Quadrilateral) {
                         JsonObject obj = adapterQuadrilateral.toJsonTree((Quadrilateral)value.getActualInstance()).getAsJsonObject();

samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/model/ShapeOrNull.java

@@ -77,6 +77,11 @@ public class ShapeOrNull extends AbstractOpenApiSchema {
             return (TypeAdapter<T>) new TypeAdapter<ShapeOrNull>() {
                 @Override
                 public void write(JsonWriter out, ShapeOrNull value) throws IOException {
+                    if (value == null || value.getActualInstance() == null) {
+                        elementAdapter.write(out, null);
+                        return;
+                    }
+
                     // check if the actual instance is of the type `Quadrilateral`
                     if (value.getActualInstance() instanceof Quadrilateral) {
                         JsonObject obj = adapterQuadrilateral.toJsonTree((Quadrilateral)value.getActualInstance()).getAsJsonObject();

samples/client/petstore/java/okhttp-gson-nextgen/src/main/java/org/openapitools/client/model/Triangle.java

@@ -79,6 +79,11 @@ public class Triangle extends AbstractOpenApiSchema {
             return (TypeAdapter<T>) new TypeAdapter<Triangle>() {
                 @Override
                 public void write(JsonWriter out, Triangle value) throws IOException {
+                    if (value == null || value.getActualInstance() == null) {
+                        elementAdapter.write(out, null);
+                        return;
+                    }
+
                     // check if the actual instance is of the type `EquilateralTriangle`
                     if (value.getActualInstance() instanceof EquilateralTriangle) {
                         JsonObject obj = adapterEquilateralTriangle.toJsonTree((EquilateralTriangle)value.getActualInstance()).getAsJsonObject();

samples/client/petstore/java/okhttp-gson-nextgen/src/test/java/org/openapitools/client/JSONTest.java

@@ -314,6 +314,13 @@ public class JSONTest {
             assertEquals(inst2.getMealy(), false);
             assertEquals(json.getGson().toJson(inst2), "{\"cultivar\":\"golden delicious\",\"mealy\":false}");
         }
+        {
+            // test to ensure the oneOf object can be serialized to "null" correctly
+            FruitReq o = new FruitReq();
+            assertEquals(o.getActualInstance(), null);
+            assertEquals(json.getGson().toJson(o), "null");
+            assertEquals(json.getGson().toJson(null), "null");
+        }
         {
             // Same test, but this time with additional (undeclared) properties.
             // Since FruitReq has additionalProperties: false, deserialization should fail.