[dart][dart-dio] Nullable support/improvements (#8727)

* [dart-dio] Disable nullable fields by default

This is not in line with the OAS and will prevent future Dart nullabilty features (NNBD) from being useful as all types would be optional.
Users can still opt-in for this.

* [dart-dio] Properties are nullable when not required AND not nullable

* [dart][dart-dio] Support nullable/required fields

* properties in built_value need to be nullable when they are nullable in OAS or when they are not required in OAS
* built_value does not support serializing `null` values by default as it is based on a serialization format based on iterables/lists and not maps
* dart-dio uses the built_value json plugin to convert the built_value format to regular json
* by generating a custom serializer for each class we can add support for serializing `null` values if the property is required AND nullable in OAS
* this is a breaking change as not all properties in the models are nullable by default anymore

* Implement required/nullable for dart

* Changes for set types and enum names after rebase

* Add some comments and fix built_value fields with default being nullable

* More rebase changes and regenerate docs

docs/generators/dart-dio.md

@@ -12,7 +12,7 @@ These options may be applied as additional-properties (cli) or configOptions (pl
 |disallowAdditionalPropertiesIfNotPresent|If false, the 'additionalProperties' implementation (set to true by default) is compliant with the OAS and JSON schema specifications. If true (default), keep the old (incorrect) behaviour that 'additionalProperties' is set to false by default.|<dl><dt>**false**</dt><dd>The 'additionalProperties' implementation is compliant with the OAS and JSON schema specifications.</dd><dt>**true**</dt><dd>Keep the old (incorrect) behaviour that 'additionalProperties' is set to false by default.</dd></dl>|true|
 |ensureUniqueParams|Whether to ensure parameter names are unique in an operation (rename parameters that are not).| |true|
 |legacyDiscriminatorBehavior|Set to true for generators with better support for discriminators. (Python, Java, Go, PowerShell, C#have this enabled by default).|<dl><dt>**true**</dt><dd>The mapping in the discriminator includes descendent schemas that allOf inherit from self and the discriminator mapping schemas in the OAS document.</dd><dt>**false**</dt><dd>The mapping in the discriminator includes any descendent schemas that allOf inherit from self, any oneOf schemas, any anyOf schemas, any x-discriminator-values, and the discriminator mapping schemas in the OAS document AND Codegen validates that oneOf and anyOf schemas contain the required discriminator and throws an error if the discriminator is missing.</dd></dl>|true|
-|nullableFields|Is the null fields should be in the JSON payload| |null|
+|nullableFields|Make all fields nullable in the JSON payload| |null|
 |prependFormOrBodyParameters|Add form or body parameters to the beginning of the parameter list.| |false|
 |pubAuthor|Author name in generated pubspec| |null|
 |pubAuthorEmail|Email address of the author in generated pubspec| |null|

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

@@ -40,7 +40,7 @@ public class DartDioClientCodegen extends DartClientCodegen {
 
     private static final String CLIENT_NAME = "clientName";
 
-    private boolean nullableFields = true;
+    private boolean nullableFields = false;
     private String dateLibrary = "core";
 
     public DartDioClientCodegen() {
@@ -49,7 +49,7 @@ public class DartDioClientCodegen extends DartClientCodegen {
         embeddedTemplateDir = "dart-dio";
         this.setTemplateDir(embeddedTemplateDir);
 
-        cliOptions.add(new CliOption(NULLABLE_FIELDS, "Is the null fields should be in the JSON payload"));
+        cliOptions.add(new CliOption(NULLABLE_FIELDS, "Make all fields nullable in the JSON payload"));
         CliOption dateLibrary = new CliOption(DATE_LIBRARY, "Option. Date library to use").defaultValue(this.getDateLibrary());
         Map<String, String> dateOptions = new HashMap<>();
         dateOptions.put("core", "Dart core library (DateTime)");
@@ -284,6 +284,34 @@ public class DartDioClientCodegen extends DartClientCodegen {
             // enums are generated with built_value and make use of BuiltSet
             model.imports.add("BuiltSet");
         }
+
+        property.getVendorExtensions().put("x-built-value-serializer-type", createBuiltValueSerializerType(property));
+    }
+
+    private String createBuiltValueSerializerType(CodegenProperty property) {
+        final StringBuilder sb = new StringBuilder("const FullType(");
+        if (property.isContainer) {
+            appendCollection(sb, property);
+        } else {
+            sb.append(property.datatypeWithEnum);
+        }
+        sb.append(")");
+        return sb.toString();
+    }
+
+    private void appendCollection(StringBuilder sb, CodegenProperty property) {
+        sb.append(property.baseType);
+        sb.append(", [FullType(");
+        if (property.isMap) {
+            // a map always has string keys
+            sb.append("String), FullType(");
+        }
+        if (property.items.isContainer) {
+            appendCollection(sb, property.items);
+        } else {
+            sb.append(property.items.datatypeWithEnum);
+        }
+        sb.append(")]");
     }
 
     @Override

modules/openapi-generator/src/main/resources/dart-dio/class.mustache

@@ -9,9 +9,20 @@ abstract class {{classname}} implements Built<{{classname}}, {{classname}}Builde
     {{#description}}
     /// {{{description}}}
     {{/description}}
+    {{!
+        A field is @nullable in built_value when it is
+        nullable || (!required && !defaultValue) in OAS
+    }}
     {{#isNullable}}
     @nullable
     {{/isNullable}}
+    {{^isNullable}}
+    {{^required}}
+    {{^defaultValue}}
+    @nullable
+    {{/defaultValue}}
+    {{/required}}
+    {{/isNullable}}
     @BuiltValueField(wireName: r'{{baseName}}')
     {{{datatypeWithEnum}}} get {{name}};
     {{#allowableValues}}
@@ -19,14 +30,89 @@ abstract class {{classname}} implements Built<{{classname}}, {{classname}}Builde
     {{/allowableValues}}
 
 {{/vars}}
-    // Boilerplate code needed to wire-up generated code
     {{classname}}._();
 
     static void _initializeBuilder({{{classname}}}Builder b) => b{{#vars}}{{#defaultValue}}
         ..{{{name}}} = {{#isEnum}}{{^isContainer}}const {{{enumName}}}._({{/isContainer}}{{/isEnum}}{{{defaultValue}}}{{#isEnum}}{{^isContainer}}){{/isContainer}}{{/isEnum}}{{/defaultValue}}{{/vars}};
 
     factory {{classname}}([void updates({{classname}}Builder b)]) = _${{classname}};
-    static Serializer<{{classname}}> get serializer => _${{#lambda.camelcase}}{{{classname}}}{{/lambda.camelcase}}Serializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<{{classname}}> get serializer => _${{classname}}Serializer();
+}
+
+{{!
+    Generate a custom serializer in order to support combinations of required and nullable.
+    By default built_value does not serialize null fields.
+}}
+class _${{classname}}Serializer implements StructuredSerializer<{{classname}}> {
+
+    @override
+    final Iterable<Type> types = const [{{classname}}, _${{classname}}];
+    @override
+    final String wireName = r'{{classname}}';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, {{{classname}}} object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        {{#vars}}
+        {{#required}}
+        {{!
+            A required property need to always be part of the serialized output.
+            When it is nullable, null is serialized, otherwise it is an error if it is null.
+        }}
+        result
+            ..add(r'{{baseName}}')
+            ..add({{#isNullable}}object.{{{name}}} == null ? null : {{/isNullable}}serializers.serialize(object.{{{name}}},
+                specifiedType: {{{vendorExtensions.x-built-value-serializer-type}}}));
+        {{/required}}
+        {{^required}}
+        if (object.{{{name}}} != null) {
+            {{! Non-required properties are only serialized if not null. }}
+            result
+                ..add(r'{{baseName}}')
+                ..add(serializers.serialize(object.{{{name}}},
+                    specifiedType: {{{vendorExtensions.x-built-value-serializer-type}}}));
+        }
+        {{/required}}
+        {{/vars}}
+        return result;
+    }
+
+    @override
+    {{classname}} deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = {{classname}}Builder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                {{#vars}}
+                case r'{{baseName}}':
+                    {{#isContainer}}
+                    result.{{{name}}}.replace(serializers.deserialize(value,
+                        specifiedType: {{{vendorExtensions.x-built-value-serializer-type}}}) as {{{datatypeWithEnum}}});
+                    {{/isContainer}}
+                    {{#isModel}}
+                    result.{{{name}}}.replace(serializers.deserialize(value,
+                        specifiedType: {{{vendorExtensions.x-built-value-serializer-type}}}) as {{{datatypeWithEnum}}});
+                    {{/isModel}}
+                    {{^isContainer}}
+                    {{^isModel}}
+                    result.{{{name}}} = serializers.deserialize(value,
+                        specifiedType: {{{vendorExtensions.x-built-value-serializer-type}}}) as {{{datatypeWithEnum}}};
+                    {{/isModel}}
+                    {{/isContainer}}
+                    break;
+                {{/vars}}
+            }
+        }
+        return result.build();
+    }
 }
 {{!
     Generate an enum for any variables that are declared as inline enums

modules/openapi-generator/src/main/resources/dart-dio/model_test.mustache

@@ -6,7 +6,9 @@ import 'package:test/test.dart';
 // tests for {{{classname}}}
 void main() {
   {{^isEnum}}
-  final instance = {{{classname}}}();
+  {{! Due to required vars without default value we can not create a full instance here }}
+  final instance = {{{classname}}}Builder();
+  // TODO add properties to the builder and call build()
   {{/isEnum}}
 
   group({{{classname}}}, () {

modules/openapi-generator/src/main/resources/dart2/class.mustache

@@ -2,7 +2,11 @@ class {{{classname}}} {
   /// Returns a new [{{{classname}}}] instance.
   {{{classname}}}({
   {{#vars}}
-    {{#required}}{{^defaultValue}}@required {{/defaultValue}}{{/required}}this.{{{name}}}{{^isNullable}}{{#defaultValue}} = {{#isEnum}}{{^isContainer}}const {{{enumName}}}._({{/isContainer}}{{/isEnum}}{{{defaultValue}}}{{#isEnum}}{{^isContainer}}){{/isContainer}}{{/isEnum}}{{/defaultValue}}{{/isNullable}},
+    {{!
+        A field is @required in Dart when it is
+        required && !nullable && !defaultValue in OAS
+    }}
+    {{#required}}{{^isNullable}}{{^defaultValue}}@required {{/defaultValue}}{{/isNullable}}{{/required}}this.{{{name}}}{{^isNullable}}{{#defaultValue}} = {{#isEnum}}{{^isContainer}}const {{{enumName}}}._({{/isContainer}}{{/isEnum}}{{{defaultValue}}}{{#isEnum}}{{^isContainer}}){{/isContainer}}{{/isEnum}}{{/defaultValue}}{{/isNullable}},
   {{/vars}}
   });
 
@@ -39,33 +43,37 @@ class {{{classname}}} {
   Map<String, dynamic> toJson() {
     final json = <String, dynamic>{};
   {{#vars}}
+    {{^required}}
     if ({{{name}}} != null) {
+    {{/required}}
     {{#isDateTime}}
       {{#pattern}}
-      json[r'{{{baseName}}}'] = _dateEpochMarker == '{{{pattern}}}'
+      json[r'{{{baseName}}}'] = {{#required}}{{#isNullable}}{{{name}}} == null ? null : {{/isNullable}}{{/required}}_dateEpochMarker == '{{{pattern}}}'
         ? {{{name}}}.millisecondsSinceEpoch
         : {{{name}}}.toUtc().toIso8601String();
       {{/pattern}}
       {{^pattern}}
-      json[r'{{{baseName}}}'] = {{{name}}}.toUtc().toIso8601String();
+      json[r'{{{baseName}}}'] = {{#required}}{{#isNullable}}{{{name}}} == null ? null : {{/isNullable}}{{/required}}{{{name}}}.toUtc().toIso8601String();
       {{/pattern}}
     {{/isDateTime}}
     {{#isDate}}
       {{#pattern}}
-      json[r'{{{baseName}}}'] = _dateEpochMarker == '{{{pattern}}}'
+      json[r'{{{baseName}}}'] = {{#required}}{{#isNullable}}{{{name}}} == null ? null : {{/isNullable}}{{/required}}_dateEpochMarker == '{{{pattern}}}'
         ? {{{name}}}.millisecondsSinceEpoch
         : _dateFormatter.format({{{name}}}.toUtc());
       {{/pattern}}
       {{^pattern}}
-      json[r'{{{baseName}}}'] = _dateFormatter.format({{{name}}}.toUtc());
+      json[r'{{{baseName}}}'] = {{#required}}{{#isNullable}}{{{name}}} == null ? null : {{/isNullable}}{{/required}}_dateFormatter.format({{{name}}}.toUtc());
       {{/pattern}}
     {{/isDate}}
     {{^isDateTime}}
       {{^isDate}}
-      json[r'{{{baseName}}}'] = {{{name}}};
+      json[r'{{{baseName}}}'] = {{#required}}{{#isNullable}}{{{name}}} == null ? null : {{/isNullable}}{{/required}}{{{name}}};
       {{/isDate}}
     {{/isDateTime}}
+    {{^required}}
     }
+    {{/required}}
   {{/vars}}
     return json;
   }

samples/client/petstore/dart-dio/petstore_client_lib/lib/model/api_response.dart

@@ -24,12 +24,74 @@ abstract class ApiResponse implements Built<ApiResponse, ApiResponseBuilder> {
     @BuiltValueField(wireName: r'message')
     String get message;
 
-    // Boilerplate code needed to wire-up generated code
     ApiResponse._();
 
     static void _initializeBuilder(ApiResponseBuilder b) => b;
 
     factory ApiResponse([void updates(ApiResponseBuilder b)]) = _$ApiResponse;
-    static Serializer<ApiResponse> get serializer => _$apiResponseSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<ApiResponse> get serializer => _$ApiResponseSerializer();
+}
+
+class _$ApiResponseSerializer implements StructuredSerializer<ApiResponse> {
+
+    @override
+    final Iterable<Type> types = const [ApiResponse, _$ApiResponse];
+    @override
+    final String wireName = r'ApiResponse';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, ApiResponse object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.code != null) {
+            result
+                ..add(r'code')
+                ..add(serializers.serialize(object.code,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.type != null) {
+            result
+                ..add(r'type')
+                ..add(serializers.serialize(object.type,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.message != null) {
+            result
+                ..add(r'message')
+                ..add(serializers.serialize(object.message,
+                    specifiedType: const FullType(String)));
+        }
+        return result;
+    }
+
+    @override
+    ApiResponse deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = ApiResponseBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'code':
+                    result.code = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'type':
+                    result.type = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'message':
+                    result.message = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/client/petstore/dart-dio/petstore_client_lib/lib/model/category.dart

@@ -20,12 +20,64 @@ abstract class Category implements Built<Category, CategoryBuilder> {
     @BuiltValueField(wireName: r'name')
     String get name;
 
-    // Boilerplate code needed to wire-up generated code
     Category._();
 
     static void _initializeBuilder(CategoryBuilder b) => b;
 
     factory Category([void updates(CategoryBuilder b)]) = _$Category;
-    static Serializer<Category> get serializer => _$categorySerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<Category> get serializer => _$CategorySerializer();
+}
+
+class _$CategorySerializer implements StructuredSerializer<Category> {
+
+    @override
+    final Iterable<Type> types = const [Category, _$Category];
+    @override
+    final String wireName = r'Category';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, Category object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.id != null) {
+            result
+                ..add(r'id')
+                ..add(serializers.serialize(object.id,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.name != null) {
+            result
+                ..add(r'name')
+                ..add(serializers.serialize(object.name,
+                    specifiedType: const FullType(String)));
+        }
+        return result;
+    }
+
+    @override
+    Category deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = CategoryBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'id':
+                    result.id = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'name':
+                    result.name = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/client/petstore/dart-dio/petstore_client_lib/lib/model/order.dart

@@ -35,18 +35,109 @@ abstract class Order implements Built<Order, OrderBuilder> {
     OrderStatusEnum get status;
     // enum statusEnum {  placed,  approved,  delivered,  };
 
-    @nullable
     @BuiltValueField(wireName: r'complete')
     bool get complete;
 
-    // Boilerplate code needed to wire-up generated code
     Order._();
 
     static void _initializeBuilder(OrderBuilder b) => b
         ..complete = false;
 
     factory Order([void updates(OrderBuilder b)]) = _$Order;
-    static Serializer<Order> get serializer => _$orderSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<Order> get serializer => _$OrderSerializer();
+}
+
+class _$OrderSerializer implements StructuredSerializer<Order> {
+
+    @override
+    final Iterable<Type> types = const [Order, _$Order];
+    @override
+    final String wireName = r'Order';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, Order object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.id != null) {
+            result
+                ..add(r'id')
+                ..add(serializers.serialize(object.id,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.petId != null) {
+            result
+                ..add(r'petId')
+                ..add(serializers.serialize(object.petId,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.quantity != null) {
+            result
+                ..add(r'quantity')
+                ..add(serializers.serialize(object.quantity,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.shipDate != null) {
+            result
+                ..add(r'shipDate')
+                ..add(serializers.serialize(object.shipDate,
+                    specifiedType: const FullType(DateTime)));
+        }
+        if (object.status != null) {
+            result
+                ..add(r'status')
+                ..add(serializers.serialize(object.status,
+                    specifiedType: const FullType(OrderStatusEnum)));
+        }
+        if (object.complete != null) {
+            result
+                ..add(r'complete')
+                ..add(serializers.serialize(object.complete,
+                    specifiedType: const FullType(bool)));
+        }
+        return result;
+    }
+
+    @override
+    Order deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = OrderBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'id':
+                    result.id = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'petId':
+                    result.petId = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'quantity':
+                    result.quantity = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'shipDate':
+                    result.shipDate = serializers.deserialize(value,
+                        specifiedType: const FullType(DateTime)) as DateTime;
+                    break;
+                case r'status':
+                    result.status = serializers.deserialize(value,
+                        specifiedType: const FullType(OrderStatusEnum)) as OrderStatusEnum;
+                    break;
+                case r'complete':
+                    result.complete = serializers.deserialize(value,
+                        specifiedType: const FullType(bool)) as bool;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 
 class OrderStatusEnum extends EnumClass {

samples/client/petstore/dart-dio/petstore_client_lib/lib/model/pet.dart

@@ -23,11 +23,9 @@ abstract class Pet implements Built<Pet, PetBuilder> {
     @BuiltValueField(wireName: r'category')
     Category get category;
 
-    @nullable
     @BuiltValueField(wireName: r'name')
     String get name;
 
-    @nullable
     @BuiltValueField(wireName: r'photoUrls')
     BuiltList<String> get photoUrls;
 
@@ -41,13 +39,101 @@ abstract class Pet implements Built<Pet, PetBuilder> {
     PetStatusEnum get status;
     // enum statusEnum {  available,  pending,  sold,  };
 
-    // Boilerplate code needed to wire-up generated code
     Pet._();
 
     static void _initializeBuilder(PetBuilder b) => b;
 
     factory Pet([void updates(PetBuilder b)]) = _$Pet;
-    static Serializer<Pet> get serializer => _$petSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<Pet> get serializer => _$PetSerializer();
+}
+
+class _$PetSerializer implements StructuredSerializer<Pet> {
+
+    @override
+    final Iterable<Type> types = const [Pet, _$Pet];
+    @override
+    final String wireName = r'Pet';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, Pet object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.id != null) {
+            result
+                ..add(r'id')
+                ..add(serializers.serialize(object.id,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.category != null) {
+            result
+                ..add(r'category')
+                ..add(serializers.serialize(object.category,
+                    specifiedType: const FullType(Category)));
+        }
+        result
+            ..add(r'name')
+            ..add(serializers.serialize(object.name,
+                specifiedType: const FullType(String)));
+        result
+            ..add(r'photoUrls')
+            ..add(serializers.serialize(object.photoUrls,
+                specifiedType: const FullType(BuiltList, [FullType(String)])));
+        if (object.tags != null) {
+            result
+                ..add(r'tags')
+                ..add(serializers.serialize(object.tags,
+                    specifiedType: const FullType(BuiltList, [FullType(Tag)])));
+        }
+        if (object.status != null) {
+            result
+                ..add(r'status')
+                ..add(serializers.serialize(object.status,
+                    specifiedType: const FullType(PetStatusEnum)));
+        }
+        return result;
+    }
+
+    @override
+    Pet deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = PetBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'id':
+                    result.id = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'category':
+                    result.category.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(Category)) as Category);
+                    break;
+                case r'name':
+                    result.name = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'photoUrls':
+                    result.photoUrls.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltList, [FullType(String)])) as BuiltList<String>);
+                    break;
+                case r'tags':
+                    result.tags.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltList, [FullType(Tag)])) as BuiltList<Tag>);
+                    break;
+                case r'status':
+                    result.status = serializers.deserialize(value,
+                        specifiedType: const FullType(PetStatusEnum)) as PetStatusEnum;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 
 class PetStatusEnum extends EnumClass {

samples/client/petstore/dart-dio/petstore_client_lib/lib/model/tag.dart

@@ -20,12 +20,64 @@ abstract class Tag implements Built<Tag, TagBuilder> {
     @BuiltValueField(wireName: r'name')
     String get name;
 
-    // Boilerplate code needed to wire-up generated code
     Tag._();
 
     static void _initializeBuilder(TagBuilder b) => b;
 
     factory Tag([void updates(TagBuilder b)]) = _$Tag;
-    static Serializer<Tag> get serializer => _$tagSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<Tag> get serializer => _$TagSerializer();
+}
+
+class _$TagSerializer implements StructuredSerializer<Tag> {
+
+    @override
+    final Iterable<Type> types = const [Tag, _$Tag];
+    @override
+    final String wireName = r'Tag';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, Tag object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.id != null) {
+            result
+                ..add(r'id')
+                ..add(serializers.serialize(object.id,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.name != null) {
+            result
+                ..add(r'name')
+                ..add(serializers.serialize(object.name,
+                    specifiedType: const FullType(String)));
+        }
+        return result;
+    }
+
+    @override
+    Tag deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = TagBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'id':
+                    result.id = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'name':
+                    result.name = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/client/petstore/dart-dio/petstore_client_lib/lib/model/user.dart

@@ -45,12 +45,124 @@ abstract class User implements Built<User, UserBuilder> {
     @BuiltValueField(wireName: r'userStatus')
     int get userStatus;
 
-    // Boilerplate code needed to wire-up generated code
     User._();
 
     static void _initializeBuilder(UserBuilder b) => b;
 
     factory User([void updates(UserBuilder b)]) = _$User;
-    static Serializer<User> get serializer => _$userSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<User> get serializer => _$UserSerializer();
+}
+
+class _$UserSerializer implements StructuredSerializer<User> {
+
+    @override
+    final Iterable<Type> types = const [User, _$User];
+    @override
+    final String wireName = r'User';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, User object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.id != null) {
+            result
+                ..add(r'id')
+                ..add(serializers.serialize(object.id,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.username != null) {
+            result
+                ..add(r'username')
+                ..add(serializers.serialize(object.username,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.firstName != null) {
+            result
+                ..add(r'firstName')
+                ..add(serializers.serialize(object.firstName,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.lastName != null) {
+            result
+                ..add(r'lastName')
+                ..add(serializers.serialize(object.lastName,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.email != null) {
+            result
+                ..add(r'email')
+                ..add(serializers.serialize(object.email,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.password != null) {
+            result
+                ..add(r'password')
+                ..add(serializers.serialize(object.password,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.phone != null) {
+            result
+                ..add(r'phone')
+                ..add(serializers.serialize(object.phone,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.userStatus != null) {
+            result
+                ..add(r'userStatus')
+                ..add(serializers.serialize(object.userStatus,
+                    specifiedType: const FullType(int)));
+        }
+        return result;
+    }
+
+    @override
+    User deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = UserBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'id':
+                    result.id = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'username':
+                    result.username = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'firstName':
+                    result.firstName = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'lastName':
+                    result.lastName = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'email':
+                    result.email = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'password':
+                    result.password = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'phone':
+                    result.phone = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'userStatus':
+                    result.userStatus = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/client/petstore/dart-dio/petstore_client_lib/test/api_response_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for ApiResponse
 void main() {
-  final instance = ApiResponse();
+  final instance = ApiResponseBuilder();
+  // TODO add properties to the builder and call build()
 
   group(ApiResponse, () {
     // int code

samples/client/petstore/dart-dio/petstore_client_lib/test/category_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for Category
 void main() {
-  final instance = Category();
+  final instance = CategoryBuilder();
+  // TODO add properties to the builder and call build()
 
   group(Category, () {
     // int id

samples/client/petstore/dart-dio/petstore_client_lib/test/order_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for Order
 void main() {
-  final instance = Order();
+  final instance = OrderBuilder();
+  // TODO add properties to the builder and call build()
 
   group(Order, () {
     // int id

samples/client/petstore/dart-dio/petstore_client_lib/test/pet_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for Pet
 void main() {
-  final instance = Pet();
+  final instance = PetBuilder();
+  // TODO add properties to the builder and call build()
 
   group(Pet, () {
     // int id

samples/client/petstore/dart-dio/petstore_client_lib/test/tag_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for Tag
 void main() {
-  final instance = Tag();
+  final instance = TagBuilder();
+  // TODO add properties to the builder and call build()
 
   group(Tag, () {
     // int id

samples/client/petstore/dart-dio/petstore_client_lib/test/user_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for User
 void main() {
-  final instance = User();
+  final instance = UserBuilder();
+  // TODO add properties to the builder and call build()
 
   group(User, () {
     // int id

samples/client/petstore/dart2/petstore_client_lib/lib/model/pet.dart

@@ -62,12 +62,8 @@ class Pet {
     if (category != null) {
       json[r'category'] = category;
     }
-    if (name != null) {
       json[r'name'] = name;
-    }
-    if (photoUrls != null) {
       json[r'photoUrls'] = photoUrls;
-    }
     if (tags != null) {
       json[r'tags'] = tags;
     }

samples/openapi3/client/petstore/dart-dio/petstore_client_lib/lib/model/api_response.dart

@@ -24,12 +24,74 @@ abstract class ApiResponse implements Built<ApiResponse, ApiResponseBuilder> {
     @BuiltValueField(wireName: r'message')
     String get message;
 
-    // Boilerplate code needed to wire-up generated code
     ApiResponse._();
 
     static void _initializeBuilder(ApiResponseBuilder b) => b;
 
     factory ApiResponse([void updates(ApiResponseBuilder b)]) = _$ApiResponse;
-    static Serializer<ApiResponse> get serializer => _$apiResponseSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<ApiResponse> get serializer => _$ApiResponseSerializer();
+}
+
+class _$ApiResponseSerializer implements StructuredSerializer<ApiResponse> {
+
+    @override
+    final Iterable<Type> types = const [ApiResponse, _$ApiResponse];
+    @override
+    final String wireName = r'ApiResponse';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, ApiResponse object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.code != null) {
+            result
+                ..add(r'code')
+                ..add(serializers.serialize(object.code,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.type != null) {
+            result
+                ..add(r'type')
+                ..add(serializers.serialize(object.type,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.message != null) {
+            result
+                ..add(r'message')
+                ..add(serializers.serialize(object.message,
+                    specifiedType: const FullType(String)));
+        }
+        return result;
+    }
+
+    @override
+    ApiResponse deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = ApiResponseBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'code':
+                    result.code = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'type':
+                    result.type = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'message':
+                    result.message = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib/lib/model/category.dart

@@ -20,12 +20,64 @@ abstract class Category implements Built<Category, CategoryBuilder> {
     @BuiltValueField(wireName: r'name')
     String get name;
 
-    // Boilerplate code needed to wire-up generated code
     Category._();
 
     static void _initializeBuilder(CategoryBuilder b) => b;
 
     factory Category([void updates(CategoryBuilder b)]) = _$Category;
-    static Serializer<Category> get serializer => _$categorySerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<Category> get serializer => _$CategorySerializer();
+}
+
+class _$CategorySerializer implements StructuredSerializer<Category> {
+
+    @override
+    final Iterable<Type> types = const [Category, _$Category];
+    @override
+    final String wireName = r'Category';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, Category object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.id != null) {
+            result
+                ..add(r'id')
+                ..add(serializers.serialize(object.id,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.name != null) {
+            result
+                ..add(r'name')
+                ..add(serializers.serialize(object.name,
+                    specifiedType: const FullType(String)));
+        }
+        return result;
+    }
+
+    @override
+    Category deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = CategoryBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'id':
+                    result.id = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'name':
+                    result.name = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib/lib/model/order.dart

@@ -35,18 +35,109 @@ abstract class Order implements Built<Order, OrderBuilder> {
     OrderStatusEnum get status;
     // enum statusEnum {  placed,  approved,  delivered,  };
 
-    @nullable
     @BuiltValueField(wireName: r'complete')
     bool get complete;
 
-    // Boilerplate code needed to wire-up generated code
     Order._();
 
     static void _initializeBuilder(OrderBuilder b) => b
         ..complete = false;
 
     factory Order([void updates(OrderBuilder b)]) = _$Order;
-    static Serializer<Order> get serializer => _$orderSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<Order> get serializer => _$OrderSerializer();
+}
+
+class _$OrderSerializer implements StructuredSerializer<Order> {
+
+    @override
+    final Iterable<Type> types = const [Order, _$Order];
+    @override
+    final String wireName = r'Order';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, Order object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.id != null) {
+            result
+                ..add(r'id')
+                ..add(serializers.serialize(object.id,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.petId != null) {
+            result
+                ..add(r'petId')
+                ..add(serializers.serialize(object.petId,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.quantity != null) {
+            result
+                ..add(r'quantity')
+                ..add(serializers.serialize(object.quantity,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.shipDate != null) {
+            result
+                ..add(r'shipDate')
+                ..add(serializers.serialize(object.shipDate,
+                    specifiedType: const FullType(DateTime)));
+        }
+        if (object.status != null) {
+            result
+                ..add(r'status')
+                ..add(serializers.serialize(object.status,
+                    specifiedType: const FullType(OrderStatusEnum)));
+        }
+        if (object.complete != null) {
+            result
+                ..add(r'complete')
+                ..add(serializers.serialize(object.complete,
+                    specifiedType: const FullType(bool)));
+        }
+        return result;
+    }
+
+    @override
+    Order deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = OrderBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'id':
+                    result.id = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'petId':
+                    result.petId = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'quantity':
+                    result.quantity = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'shipDate':
+                    result.shipDate = serializers.deserialize(value,
+                        specifiedType: const FullType(DateTime)) as DateTime;
+                    break;
+                case r'status':
+                    result.status = serializers.deserialize(value,
+                        specifiedType: const FullType(OrderStatusEnum)) as OrderStatusEnum;
+                    break;
+                case r'complete':
+                    result.complete = serializers.deserialize(value,
+                        specifiedType: const FullType(bool)) as bool;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 
 class OrderStatusEnum extends EnumClass {

samples/openapi3/client/petstore/dart-dio/petstore_client_lib/lib/model/pet.dart

@@ -23,11 +23,9 @@ abstract class Pet implements Built<Pet, PetBuilder> {
     @BuiltValueField(wireName: r'category')
     Category get category;
 
-    @nullable
     @BuiltValueField(wireName: r'name')
     String get name;
 
-    @nullable
     @BuiltValueField(wireName: r'photoUrls')
     BuiltList<String> get photoUrls;
 
@@ -41,13 +39,101 @@ abstract class Pet implements Built<Pet, PetBuilder> {
     PetStatusEnum get status;
     // enum statusEnum {  available,  pending,  sold,  };
 
-    // Boilerplate code needed to wire-up generated code
     Pet._();
 
     static void _initializeBuilder(PetBuilder b) => b;
 
     factory Pet([void updates(PetBuilder b)]) = _$Pet;
-    static Serializer<Pet> get serializer => _$petSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<Pet> get serializer => _$PetSerializer();
+}
+
+class _$PetSerializer implements StructuredSerializer<Pet> {
+
+    @override
+    final Iterable<Type> types = const [Pet, _$Pet];
+    @override
+    final String wireName = r'Pet';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, Pet object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.id != null) {
+            result
+                ..add(r'id')
+                ..add(serializers.serialize(object.id,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.category != null) {
+            result
+                ..add(r'category')
+                ..add(serializers.serialize(object.category,
+                    specifiedType: const FullType(Category)));
+        }
+        result
+            ..add(r'name')
+            ..add(serializers.serialize(object.name,
+                specifiedType: const FullType(String)));
+        result
+            ..add(r'photoUrls')
+            ..add(serializers.serialize(object.photoUrls,
+                specifiedType: const FullType(BuiltList, [FullType(String)])));
+        if (object.tags != null) {
+            result
+                ..add(r'tags')
+                ..add(serializers.serialize(object.tags,
+                    specifiedType: const FullType(BuiltList, [FullType(Tag)])));
+        }
+        if (object.status != null) {
+            result
+                ..add(r'status')
+                ..add(serializers.serialize(object.status,
+                    specifiedType: const FullType(PetStatusEnum)));
+        }
+        return result;
+    }
+
+    @override
+    Pet deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = PetBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'id':
+                    result.id = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'category':
+                    result.category.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(Category)) as Category);
+                    break;
+                case r'name':
+                    result.name = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'photoUrls':
+                    result.photoUrls.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltList, [FullType(String)])) as BuiltList<String>);
+                    break;
+                case r'tags':
+                    result.tags.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltList, [FullType(Tag)])) as BuiltList<Tag>);
+                    break;
+                case r'status':
+                    result.status = serializers.deserialize(value,
+                        specifiedType: const FullType(PetStatusEnum)) as PetStatusEnum;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 
 class PetStatusEnum extends EnumClass {

samples/openapi3/client/petstore/dart-dio/petstore_client_lib/lib/model/tag.dart

@@ -20,12 +20,64 @@ abstract class Tag implements Built<Tag, TagBuilder> {
     @BuiltValueField(wireName: r'name')
     String get name;
 
-    // Boilerplate code needed to wire-up generated code
     Tag._();
 
     static void _initializeBuilder(TagBuilder b) => b;
 
     factory Tag([void updates(TagBuilder b)]) = _$Tag;
-    static Serializer<Tag> get serializer => _$tagSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<Tag> get serializer => _$TagSerializer();
+}
+
+class _$TagSerializer implements StructuredSerializer<Tag> {
+
+    @override
+    final Iterable<Type> types = const [Tag, _$Tag];
+    @override
+    final String wireName = r'Tag';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, Tag object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.id != null) {
+            result
+                ..add(r'id')
+                ..add(serializers.serialize(object.id,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.name != null) {
+            result
+                ..add(r'name')
+                ..add(serializers.serialize(object.name,
+                    specifiedType: const FullType(String)));
+        }
+        return result;
+    }
+
+    @override
+    Tag deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = TagBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'id':
+                    result.id = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'name':
+                    result.name = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib/lib/model/user.dart

@@ -45,12 +45,124 @@ abstract class User implements Built<User, UserBuilder> {
     @BuiltValueField(wireName: r'userStatus')
     int get userStatus;
 
-    // Boilerplate code needed to wire-up generated code
     User._();
 
     static void _initializeBuilder(UserBuilder b) => b;
 
     factory User([void updates(UserBuilder b)]) = _$User;
-    static Serializer<User> get serializer => _$userSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<User> get serializer => _$UserSerializer();
+}
+
+class _$UserSerializer implements StructuredSerializer<User> {
+
+    @override
+    final Iterable<Type> types = const [User, _$User];
+    @override
+    final String wireName = r'User';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, User object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.id != null) {
+            result
+                ..add(r'id')
+                ..add(serializers.serialize(object.id,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.username != null) {
+            result
+                ..add(r'username')
+                ..add(serializers.serialize(object.username,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.firstName != null) {
+            result
+                ..add(r'firstName')
+                ..add(serializers.serialize(object.firstName,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.lastName != null) {
+            result
+                ..add(r'lastName')
+                ..add(serializers.serialize(object.lastName,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.email != null) {
+            result
+                ..add(r'email')
+                ..add(serializers.serialize(object.email,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.password != null) {
+            result
+                ..add(r'password')
+                ..add(serializers.serialize(object.password,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.phone != null) {
+            result
+                ..add(r'phone')
+                ..add(serializers.serialize(object.phone,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.userStatus != null) {
+            result
+                ..add(r'userStatus')
+                ..add(serializers.serialize(object.userStatus,
+                    specifiedType: const FullType(int)));
+        }
+        return result;
+    }
+
+    @override
+    User deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = UserBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'id':
+                    result.id = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'username':
+                    result.username = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'firstName':
+                    result.firstName = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'lastName':
+                    result.lastName = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'email':
+                    result.email = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'password':
+                    result.password = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'phone':
+                    result.phone = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'userStatus':
+                    result.userStatus = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib/test/api_response_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for ApiResponse
 void main() {
-  final instance = ApiResponse();
+  final instance = ApiResponseBuilder();
+  // TODO add properties to the builder and call build()
 
   group(ApiResponse, () {
     // int code

samples/openapi3/client/petstore/dart-dio/petstore_client_lib/test/category_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for Category
 void main() {
-  final instance = Category();
+  final instance = CategoryBuilder();
+  // TODO add properties to the builder and call build()
 
   group(Category, () {
     // int id

samples/openapi3/client/petstore/dart-dio/petstore_client_lib/test/order_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for Order
 void main() {
-  final instance = Order();
+  final instance = OrderBuilder();
+  // TODO add properties to the builder and call build()
 
   group(Order, () {
     // int id

samples/openapi3/client/petstore/dart-dio/petstore_client_lib/test/pet_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for Pet
 void main() {
-  final instance = Pet();
+  final instance = PetBuilder();
+  // TODO add properties to the builder and call build()
 
   group(Pet, () {
     // int id

samples/openapi3/client/petstore/dart-dio/petstore_client_lib/test/tag_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for Tag
 void main() {
-  final instance = Tag();
+  final instance = TagBuilder();
+  // TODO add properties to the builder and call build()
 
   group(Tag, () {
     // int id

samples/openapi3/client/petstore/dart-dio/petstore_client_lib/test/user_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for User
 void main() {
-  final instance = User();
+  final instance = UserBuilder();
+  // TODO add properties to the builder and call build()
 
   group(User, () {
     // int id

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/additional_properties_class.dart

@@ -21,12 +21,64 @@ abstract class AdditionalPropertiesClass implements Built<AdditionalPropertiesCl
     @BuiltValueField(wireName: r'map_of_map_property')
     BuiltMap<String, BuiltMap<String, String>> get mapOfMapProperty;
 
-    // Boilerplate code needed to wire-up generated code
     AdditionalPropertiesClass._();
 
     static void _initializeBuilder(AdditionalPropertiesClassBuilder b) => b;
 
     factory AdditionalPropertiesClass([void updates(AdditionalPropertiesClassBuilder b)]) = _$AdditionalPropertiesClass;
-    static Serializer<AdditionalPropertiesClass> get serializer => _$additionalPropertiesClassSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<AdditionalPropertiesClass> get serializer => _$AdditionalPropertiesClassSerializer();
+}
+
+class _$AdditionalPropertiesClassSerializer implements StructuredSerializer<AdditionalPropertiesClass> {
+
+    @override
+    final Iterable<Type> types = const [AdditionalPropertiesClass, _$AdditionalPropertiesClass];
+    @override
+    final String wireName = r'AdditionalPropertiesClass';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, AdditionalPropertiesClass object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.mapProperty != null) {
+            result
+                ..add(r'map_property')
+                ..add(serializers.serialize(object.mapProperty,
+                    specifiedType: const FullType(BuiltMap, [FullType(String), FullType(String)])));
+        }
+        if (object.mapOfMapProperty != null) {
+            result
+                ..add(r'map_of_map_property')
+                ..add(serializers.serialize(object.mapOfMapProperty,
+                    specifiedType: const FullType(BuiltMap, [FullType(String), FullType(BuiltMap, [FullType(String), FullType(String)])])));
+        }
+        return result;
+    }
+
+    @override
+    AdditionalPropertiesClass deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = AdditionalPropertiesClassBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'map_property':
+                    result.mapProperty.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltMap, [FullType(String), FullType(String)])) as BuiltMap<String, String>);
+                    break;
+                case r'map_of_map_property':
+                    result.mapOfMapProperty.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltMap, [FullType(String), FullType(BuiltMap, [FullType(String), FullType(String)])])) as BuiltMap<String, BuiltMap<String, String>>);
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/animal.dart

@@ -12,21 +12,69 @@ part 'animal.g.dart';
 
 abstract class Animal implements Built<Animal, AnimalBuilder> {
 
-    @nullable
     @BuiltValueField(wireName: r'className')
     String get className;
 
-    @nullable
     @BuiltValueField(wireName: r'color')
     String get color;
 
-    // Boilerplate code needed to wire-up generated code
     Animal._();
 
     static void _initializeBuilder(AnimalBuilder b) => b
         ..color = 'red';
 
     factory Animal([void updates(AnimalBuilder b)]) = _$Animal;
-    static Serializer<Animal> get serializer => _$animalSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<Animal> get serializer => _$AnimalSerializer();
+}
+
+class _$AnimalSerializer implements StructuredSerializer<Animal> {
+
+    @override
+    final Iterable<Type> types = const [Animal, _$Animal];
+    @override
+    final String wireName = r'Animal';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, Animal object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        result
+            ..add(r'className')
+            ..add(serializers.serialize(object.className,
+                specifiedType: const FullType(String)));
+        if (object.color != null) {
+            result
+                ..add(r'color')
+                ..add(serializers.serialize(object.color,
+                    specifiedType: const FullType(String)));
+        }
+        return result;
+    }
+
+    @override
+    Animal deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = AnimalBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'className':
+                    result.className = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'color':
+                    result.color = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/api_response.dart

@@ -24,12 +24,74 @@ abstract class ApiResponse implements Built<ApiResponse, ApiResponseBuilder> {
     @BuiltValueField(wireName: r'message')
     String get message;
 
-    // Boilerplate code needed to wire-up generated code
     ApiResponse._();
 
     static void _initializeBuilder(ApiResponseBuilder b) => b;
 
     factory ApiResponse([void updates(ApiResponseBuilder b)]) = _$ApiResponse;
-    static Serializer<ApiResponse> get serializer => _$apiResponseSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<ApiResponse> get serializer => _$ApiResponseSerializer();
+}
+
+class _$ApiResponseSerializer implements StructuredSerializer<ApiResponse> {
+
+    @override
+    final Iterable<Type> types = const [ApiResponse, _$ApiResponse];
+    @override
+    final String wireName = r'ApiResponse';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, ApiResponse object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.code != null) {
+            result
+                ..add(r'code')
+                ..add(serializers.serialize(object.code,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.type != null) {
+            result
+                ..add(r'type')
+                ..add(serializers.serialize(object.type,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.message != null) {
+            result
+                ..add(r'message')
+                ..add(serializers.serialize(object.message,
+                    specifiedType: const FullType(String)));
+        }
+        return result;
+    }
+
+    @override
+    ApiResponse deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = ApiResponseBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'code':
+                    result.code = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'type':
+                    result.type = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'message':
+                    result.message = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/array_of_array_of_number_only.dart

@@ -17,12 +17,54 @@ abstract class ArrayOfArrayOfNumberOnly implements Built<ArrayOfArrayOfNumberOnl
     @BuiltValueField(wireName: r'ArrayArrayNumber')
     BuiltList<BuiltList<num>> get arrayArrayNumber;
 
-    // Boilerplate code needed to wire-up generated code
     ArrayOfArrayOfNumberOnly._();
 
     static void _initializeBuilder(ArrayOfArrayOfNumberOnlyBuilder b) => b;
 
     factory ArrayOfArrayOfNumberOnly([void updates(ArrayOfArrayOfNumberOnlyBuilder b)]) = _$ArrayOfArrayOfNumberOnly;
-    static Serializer<ArrayOfArrayOfNumberOnly> get serializer => _$arrayOfArrayOfNumberOnlySerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<ArrayOfArrayOfNumberOnly> get serializer => _$ArrayOfArrayOfNumberOnlySerializer();
+}
+
+class _$ArrayOfArrayOfNumberOnlySerializer implements StructuredSerializer<ArrayOfArrayOfNumberOnly> {
+
+    @override
+    final Iterable<Type> types = const [ArrayOfArrayOfNumberOnly, _$ArrayOfArrayOfNumberOnly];
+    @override
+    final String wireName = r'ArrayOfArrayOfNumberOnly';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, ArrayOfArrayOfNumberOnly object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.arrayArrayNumber != null) {
+            result
+                ..add(r'ArrayArrayNumber')
+                ..add(serializers.serialize(object.arrayArrayNumber,
+                    specifiedType: const FullType(BuiltList, [FullType(BuiltList, [FullType(num)])])));
+        }
+        return result;
+    }
+
+    @override
+    ArrayOfArrayOfNumberOnly deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = ArrayOfArrayOfNumberOnlyBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'ArrayArrayNumber':
+                    result.arrayArrayNumber.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltList, [FullType(BuiltList, [FullType(num)])])) as BuiltList<BuiltList<num>>);
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/array_of_number_only.dart

@@ -17,12 +17,54 @@ abstract class ArrayOfNumberOnly implements Built<ArrayOfNumberOnly, ArrayOfNumb
     @BuiltValueField(wireName: r'ArrayNumber')
     BuiltList<num> get arrayNumber;
 
-    // Boilerplate code needed to wire-up generated code
     ArrayOfNumberOnly._();
 
     static void _initializeBuilder(ArrayOfNumberOnlyBuilder b) => b;
 
     factory ArrayOfNumberOnly([void updates(ArrayOfNumberOnlyBuilder b)]) = _$ArrayOfNumberOnly;
-    static Serializer<ArrayOfNumberOnly> get serializer => _$arrayOfNumberOnlySerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<ArrayOfNumberOnly> get serializer => _$ArrayOfNumberOnlySerializer();
+}
+
+class _$ArrayOfNumberOnlySerializer implements StructuredSerializer<ArrayOfNumberOnly> {
+
+    @override
+    final Iterable<Type> types = const [ArrayOfNumberOnly, _$ArrayOfNumberOnly];
+    @override
+    final String wireName = r'ArrayOfNumberOnly';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, ArrayOfNumberOnly object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.arrayNumber != null) {
+            result
+                ..add(r'ArrayNumber')
+                ..add(serializers.serialize(object.arrayNumber,
+                    specifiedType: const FullType(BuiltList, [FullType(num)])));
+        }
+        return result;
+    }
+
+    @override
+    ArrayOfNumberOnly deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = ArrayOfNumberOnlyBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'ArrayNumber':
+                    result.arrayNumber.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltList, [FullType(num)])) as BuiltList<num>);
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/array_test.dart

@@ -26,12 +26,74 @@ abstract class ArrayTest implements Built<ArrayTest, ArrayTestBuilder> {
     @BuiltValueField(wireName: r'array_array_of_model')
     BuiltList<BuiltList<ReadOnlyFirst>> get arrayArrayOfModel;
 
-    // Boilerplate code needed to wire-up generated code
     ArrayTest._();
 
     static void _initializeBuilder(ArrayTestBuilder b) => b;
 
     factory ArrayTest([void updates(ArrayTestBuilder b)]) = _$ArrayTest;
-    static Serializer<ArrayTest> get serializer => _$arrayTestSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<ArrayTest> get serializer => _$ArrayTestSerializer();
+}
+
+class _$ArrayTestSerializer implements StructuredSerializer<ArrayTest> {
+
+    @override
+    final Iterable<Type> types = const [ArrayTest, _$ArrayTest];
+    @override
+    final String wireName = r'ArrayTest';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, ArrayTest object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.arrayOfString != null) {
+            result
+                ..add(r'array_of_string')
+                ..add(serializers.serialize(object.arrayOfString,
+                    specifiedType: const FullType(BuiltList, [FullType(String)])));
+        }
+        if (object.arrayArrayOfInteger != null) {
+            result
+                ..add(r'array_array_of_integer')
+                ..add(serializers.serialize(object.arrayArrayOfInteger,
+                    specifiedType: const FullType(BuiltList, [FullType(BuiltList, [FullType(int)])])));
+        }
+        if (object.arrayArrayOfModel != null) {
+            result
+                ..add(r'array_array_of_model')
+                ..add(serializers.serialize(object.arrayArrayOfModel,
+                    specifiedType: const FullType(BuiltList, [FullType(BuiltList, [FullType(ReadOnlyFirst)])])));
+        }
+        return result;
+    }
+
+    @override
+    ArrayTest deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = ArrayTestBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'array_of_string':
+                    result.arrayOfString.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltList, [FullType(String)])) as BuiltList<String>);
+                    break;
+                case r'array_array_of_integer':
+                    result.arrayArrayOfInteger.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltList, [FullType(BuiltList, [FullType(int)])])) as BuiltList<BuiltList<int>>);
+                    break;
+                case r'array_array_of_model':
+                    result.arrayArrayOfModel.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltList, [FullType(BuiltList, [FullType(ReadOnlyFirst)])])) as BuiltList<BuiltList<ReadOnlyFirst>>);
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/capitalization.dart

@@ -37,12 +37,104 @@ abstract class Capitalization implements Built<Capitalization, CapitalizationBui
     @BuiltValueField(wireName: r'ATT_NAME')
     String get ATT_NAME;
 
-    // Boilerplate code needed to wire-up generated code
     Capitalization._();
 
     static void _initializeBuilder(CapitalizationBuilder b) => b;
 
     factory Capitalization([void updates(CapitalizationBuilder b)]) = _$Capitalization;
-    static Serializer<Capitalization> get serializer => _$capitalizationSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<Capitalization> get serializer => _$CapitalizationSerializer();
+}
+
+class _$CapitalizationSerializer implements StructuredSerializer<Capitalization> {
+
+    @override
+    final Iterable<Type> types = const [Capitalization, _$Capitalization];
+    @override
+    final String wireName = r'Capitalization';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, Capitalization object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.smallCamel != null) {
+            result
+                ..add(r'smallCamel')
+                ..add(serializers.serialize(object.smallCamel,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.capitalCamel != null) {
+            result
+                ..add(r'CapitalCamel')
+                ..add(serializers.serialize(object.capitalCamel,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.smallSnake != null) {
+            result
+                ..add(r'small_Snake')
+                ..add(serializers.serialize(object.smallSnake,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.capitalSnake != null) {
+            result
+                ..add(r'Capital_Snake')
+                ..add(serializers.serialize(object.capitalSnake,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.sCAETHFlowPoints != null) {
+            result
+                ..add(r'SCA_ETH_Flow_Points')
+                ..add(serializers.serialize(object.sCAETHFlowPoints,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.ATT_NAME != null) {
+            result
+                ..add(r'ATT_NAME')
+                ..add(serializers.serialize(object.ATT_NAME,
+                    specifiedType: const FullType(String)));
+        }
+        return result;
+    }
+
+    @override
+    Capitalization deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = CapitalizationBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'smallCamel':
+                    result.smallCamel = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'CapitalCamel':
+                    result.capitalCamel = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'small_Snake':
+                    result.smallSnake = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'Capital_Snake':
+                    result.capitalSnake = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'SCA_ETH_Flow_Points':
+                    result.sCAETHFlowPoints = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'ATT_NAME':
+                    result.ATT_NAME = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/cat.dart

@@ -14,11 +14,9 @@ part 'cat.g.dart';
 
 abstract class Cat implements Built<Cat, CatBuilder> {
 
-    @nullable
     @BuiltValueField(wireName: r'className')
     String get className;
 
-    @nullable
     @BuiltValueField(wireName: r'color')
     String get color;
 
@@ -26,13 +24,73 @@ abstract class Cat implements Built<Cat, CatBuilder> {
     @BuiltValueField(wireName: r'declawed')
     bool get declawed;
 
-    // Boilerplate code needed to wire-up generated code
     Cat._();
 
     static void _initializeBuilder(CatBuilder b) => b
         ..color = 'red';
 
     factory Cat([void updates(CatBuilder b)]) = _$Cat;
-    static Serializer<Cat> get serializer => _$catSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<Cat> get serializer => _$CatSerializer();
+}
+
+class _$CatSerializer implements StructuredSerializer<Cat> {
+
+    @override
+    final Iterable<Type> types = const [Cat, _$Cat];
+    @override
+    final String wireName = r'Cat';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, Cat object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        result
+            ..add(r'className')
+            ..add(serializers.serialize(object.className,
+                specifiedType: const FullType(String)));
+        if (object.color != null) {
+            result
+                ..add(r'color')
+                ..add(serializers.serialize(object.color,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.declawed != null) {
+            result
+                ..add(r'declawed')
+                ..add(serializers.serialize(object.declawed,
+                    specifiedType: const FullType(bool)));
+        }
+        return result;
+    }
+
+    @override
+    Cat deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = CatBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'className':
+                    result.className = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'color':
+                    result.color = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'declawed':
+                    result.declawed = serializers.deserialize(value,
+                        specifiedType: const FullType(bool)) as bool;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/cat_all_of.dart

@@ -16,12 +16,54 @@ abstract class CatAllOf implements Built<CatAllOf, CatAllOfBuilder> {
     @BuiltValueField(wireName: r'declawed')
     bool get declawed;
 
-    // Boilerplate code needed to wire-up generated code
     CatAllOf._();
 
     static void _initializeBuilder(CatAllOfBuilder b) => b;
 
     factory CatAllOf([void updates(CatAllOfBuilder b)]) = _$CatAllOf;
-    static Serializer<CatAllOf> get serializer => _$catAllOfSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<CatAllOf> get serializer => _$CatAllOfSerializer();
+}
+
+class _$CatAllOfSerializer implements StructuredSerializer<CatAllOf> {
+
+    @override
+    final Iterable<Type> types = const [CatAllOf, _$CatAllOf];
+    @override
+    final String wireName = r'CatAllOf';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, CatAllOf object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.declawed != null) {
+            result
+                ..add(r'declawed')
+                ..add(serializers.serialize(object.declawed,
+                    specifiedType: const FullType(bool)));
+        }
+        return result;
+    }
+
+    @override
+    CatAllOf deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = CatAllOfBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'declawed':
+                    result.declawed = serializers.deserialize(value,
+                        specifiedType: const FullType(bool)) as bool;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/category.dart

@@ -16,17 +16,66 @@ abstract class Category implements Built<Category, CategoryBuilder> {
     @BuiltValueField(wireName: r'id')
     int get id;
 
-    @nullable
     @BuiltValueField(wireName: r'name')
     String get name;
 
-    // Boilerplate code needed to wire-up generated code
     Category._();
 
     static void _initializeBuilder(CategoryBuilder b) => b
         ..name = 'default-name';
 
     factory Category([void updates(CategoryBuilder b)]) = _$Category;
-    static Serializer<Category> get serializer => _$categorySerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<Category> get serializer => _$CategorySerializer();
+}
+
+class _$CategorySerializer implements StructuredSerializer<Category> {
+
+    @override
+    final Iterable<Type> types = const [Category, _$Category];
+    @override
+    final String wireName = r'Category';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, Category object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.id != null) {
+            result
+                ..add(r'id')
+                ..add(serializers.serialize(object.id,
+                    specifiedType: const FullType(int)));
+        }
+        result
+            ..add(r'name')
+            ..add(serializers.serialize(object.name,
+                specifiedType: const FullType(String)));
+        return result;
+    }
+
+    @override
+    Category deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = CategoryBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'id':
+                    result.id = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'name':
+                    result.name = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/class_model.dart

@@ -16,12 +16,54 @@ abstract class ClassModel implements Built<ClassModel, ClassModelBuilder> {
     @BuiltValueField(wireName: r'_class')
     String get class_;
 
-    // Boilerplate code needed to wire-up generated code
     ClassModel._();
 
     static void _initializeBuilder(ClassModelBuilder b) => b;
 
     factory ClassModel([void updates(ClassModelBuilder b)]) = _$ClassModel;
-    static Serializer<ClassModel> get serializer => _$classModelSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<ClassModel> get serializer => _$ClassModelSerializer();
+}
+
+class _$ClassModelSerializer implements StructuredSerializer<ClassModel> {
+
+    @override
+    final Iterable<Type> types = const [ClassModel, _$ClassModel];
+    @override
+    final String wireName = r'ClassModel';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, ClassModel object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.class_ != null) {
+            result
+                ..add(r'_class')
+                ..add(serializers.serialize(object.class_,
+                    specifiedType: const FullType(String)));
+        }
+        return result;
+    }
+
+    @override
+    ClassModel deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = ClassModelBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'_class':
+                    result.class_ = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/dog.dart

@@ -14,11 +14,9 @@ part 'dog.g.dart';
 
 abstract class Dog implements Built<Dog, DogBuilder> {
 
-    @nullable
     @BuiltValueField(wireName: r'className')
     String get className;
 
-    @nullable
     @BuiltValueField(wireName: r'color')
     String get color;
 
@@ -26,13 +24,73 @@ abstract class Dog implements Built<Dog, DogBuilder> {
     @BuiltValueField(wireName: r'breed')
     String get breed;
 
-    // Boilerplate code needed to wire-up generated code
     Dog._();
 
     static void _initializeBuilder(DogBuilder b) => b
         ..color = 'red';
 
     factory Dog([void updates(DogBuilder b)]) = _$Dog;
-    static Serializer<Dog> get serializer => _$dogSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<Dog> get serializer => _$DogSerializer();
+}
+
+class _$DogSerializer implements StructuredSerializer<Dog> {
+
+    @override
+    final Iterable<Type> types = const [Dog, _$Dog];
+    @override
+    final String wireName = r'Dog';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, Dog object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        result
+            ..add(r'className')
+            ..add(serializers.serialize(object.className,
+                specifiedType: const FullType(String)));
+        if (object.color != null) {
+            result
+                ..add(r'color')
+                ..add(serializers.serialize(object.color,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.breed != null) {
+            result
+                ..add(r'breed')
+                ..add(serializers.serialize(object.breed,
+                    specifiedType: const FullType(String)));
+        }
+        return result;
+    }
+
+    @override
+    Dog deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = DogBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'className':
+                    result.className = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'color':
+                    result.color = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'breed':
+                    result.breed = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/dog_all_of.dart

@@ -16,12 +16,54 @@ abstract class DogAllOf implements Built<DogAllOf, DogAllOfBuilder> {
     @BuiltValueField(wireName: r'breed')
     String get breed;
 
-    // Boilerplate code needed to wire-up generated code
     DogAllOf._();
 
     static void _initializeBuilder(DogAllOfBuilder b) => b;
 
     factory DogAllOf([void updates(DogAllOfBuilder b)]) = _$DogAllOf;
-    static Serializer<DogAllOf> get serializer => _$dogAllOfSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<DogAllOf> get serializer => _$DogAllOfSerializer();
+}
+
+class _$DogAllOfSerializer implements StructuredSerializer<DogAllOf> {
+
+    @override
+    final Iterable<Type> types = const [DogAllOf, _$DogAllOf];
+    @override
+    final String wireName = r'DogAllOf';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, DogAllOf object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.breed != null) {
+            result
+                ..add(r'breed')
+                ..add(serializers.serialize(object.breed,
+                    specifiedType: const FullType(String)));
+        }
+        return result;
+    }
+
+    @override
+    DogAllOf deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = DogAllOfBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'breed':
+                    result.breed = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/enum_arrays.dart

@@ -23,13 +23,65 @@ abstract class EnumArrays implements Built<EnumArrays, EnumArraysBuilder> {
     BuiltList<EnumArraysArrayEnumEnum> get arrayEnum;
     // enum arrayEnumEnum {  fish,  crab,  };
 
-    // Boilerplate code needed to wire-up generated code
     EnumArrays._();
 
     static void _initializeBuilder(EnumArraysBuilder b) => b;
 
     factory EnumArrays([void updates(EnumArraysBuilder b)]) = _$EnumArrays;
-    static Serializer<EnumArrays> get serializer => _$enumArraysSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<EnumArrays> get serializer => _$EnumArraysSerializer();
+}
+
+class _$EnumArraysSerializer implements StructuredSerializer<EnumArrays> {
+
+    @override
+    final Iterable<Type> types = const [EnumArrays, _$EnumArrays];
+    @override
+    final String wireName = r'EnumArrays';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, EnumArrays object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.justSymbol != null) {
+            result
+                ..add(r'just_symbol')
+                ..add(serializers.serialize(object.justSymbol,
+                    specifiedType: const FullType(EnumArraysJustSymbolEnum)));
+        }
+        if (object.arrayEnum != null) {
+            result
+                ..add(r'array_enum')
+                ..add(serializers.serialize(object.arrayEnum,
+                    specifiedType: const FullType(BuiltList, [FullType(EnumArraysArrayEnumEnum)])));
+        }
+        return result;
+    }
+
+    @override
+    EnumArrays deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = EnumArraysBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'just_symbol':
+                    result.justSymbol = serializers.deserialize(value,
+                        specifiedType: const FullType(EnumArraysJustSymbolEnum)) as EnumArraysJustSymbolEnum;
+                    break;
+                case r'array_enum':
+                    result.arrayEnum.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltList, [FullType(EnumArraysArrayEnumEnum)])) as BuiltList<EnumArraysArrayEnumEnum>);
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 
 class EnumArraysJustSymbolEnum extends EnumClass {

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/enum_test.dart

@@ -22,7 +22,6 @@ abstract class EnumTest implements Built<EnumTest, EnumTestBuilder> {
     EnumTestEnumStringEnum get enumString;
     // enum enumStringEnum {  UPPER,  lower,  ,  };
 
-    @nullable
     @BuiltValueField(wireName: r'enum_string_required')
     EnumTestEnumStringRequiredEnum get enumStringRequired;
     // enum enumStringRequiredEnum {  UPPER,  lower,  ,  };
@@ -57,13 +56,123 @@ abstract class EnumTest implements Built<EnumTest, EnumTestBuilder> {
     OuterEnumIntegerDefaultValue get outerEnumIntegerDefaultValue;
     // enum outerEnumIntegerDefaultValueEnum {  0,  1,  2,  };
 
-    // Boilerplate code needed to wire-up generated code
     EnumTest._();
 
     static void _initializeBuilder(EnumTestBuilder b) => b;
 
     factory EnumTest([void updates(EnumTestBuilder b)]) = _$EnumTest;
-    static Serializer<EnumTest> get serializer => _$enumTestSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<EnumTest> get serializer => _$EnumTestSerializer();
+}
+
+class _$EnumTestSerializer implements StructuredSerializer<EnumTest> {
+
+    @override
+    final Iterable<Type> types = const [EnumTest, _$EnumTest];
+    @override
+    final String wireName = r'EnumTest';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, EnumTest object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.enumString != null) {
+            result
+                ..add(r'enum_string')
+                ..add(serializers.serialize(object.enumString,
+                    specifiedType: const FullType(EnumTestEnumStringEnum)));
+        }
+        result
+            ..add(r'enum_string_required')
+            ..add(serializers.serialize(object.enumStringRequired,
+                specifiedType: const FullType(EnumTestEnumStringRequiredEnum)));
+        if (object.enumInteger != null) {
+            result
+                ..add(r'enum_integer')
+                ..add(serializers.serialize(object.enumInteger,
+                    specifiedType: const FullType(EnumTestEnumIntegerEnum)));
+        }
+        if (object.enumNumber != null) {
+            result
+                ..add(r'enum_number')
+                ..add(serializers.serialize(object.enumNumber,
+                    specifiedType: const FullType(EnumTestEnumNumberEnum)));
+        }
+        if (object.outerEnum != null) {
+            result
+                ..add(r'outerEnum')
+                ..add(serializers.serialize(object.outerEnum,
+                    specifiedType: const FullType(OuterEnum)));
+        }
+        if (object.outerEnumInteger != null) {
+            result
+                ..add(r'outerEnumInteger')
+                ..add(serializers.serialize(object.outerEnumInteger,
+                    specifiedType: const FullType(OuterEnumInteger)));
+        }
+        if (object.outerEnumDefaultValue != null) {
+            result
+                ..add(r'outerEnumDefaultValue')
+                ..add(serializers.serialize(object.outerEnumDefaultValue,
+                    specifiedType: const FullType(OuterEnumDefaultValue)));
+        }
+        if (object.outerEnumIntegerDefaultValue != null) {
+            result
+                ..add(r'outerEnumIntegerDefaultValue')
+                ..add(serializers.serialize(object.outerEnumIntegerDefaultValue,
+                    specifiedType: const FullType(OuterEnumIntegerDefaultValue)));
+        }
+        return result;
+    }
+
+    @override
+    EnumTest deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = EnumTestBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'enum_string':
+                    result.enumString = serializers.deserialize(value,
+                        specifiedType: const FullType(EnumTestEnumStringEnum)) as EnumTestEnumStringEnum;
+                    break;
+                case r'enum_string_required':
+                    result.enumStringRequired = serializers.deserialize(value,
+                        specifiedType: const FullType(EnumTestEnumStringRequiredEnum)) as EnumTestEnumStringRequiredEnum;
+                    break;
+                case r'enum_integer':
+                    result.enumInteger = serializers.deserialize(value,
+                        specifiedType: const FullType(EnumTestEnumIntegerEnum)) as EnumTestEnumIntegerEnum;
+                    break;
+                case r'enum_number':
+                    result.enumNumber = serializers.deserialize(value,
+                        specifiedType: const FullType(EnumTestEnumNumberEnum)) as EnumTestEnumNumberEnum;
+                    break;
+                case r'outerEnum':
+                    result.outerEnum = serializers.deserialize(value,
+                        specifiedType: const FullType(OuterEnum)) as OuterEnum;
+                    break;
+                case r'outerEnumInteger':
+                    result.outerEnumInteger = serializers.deserialize(value,
+                        specifiedType: const FullType(OuterEnumInteger)) as OuterEnumInteger;
+                    break;
+                case r'outerEnumDefaultValue':
+                    result.outerEnumDefaultValue = serializers.deserialize(value,
+                        specifiedType: const FullType(OuterEnumDefaultValue)) as OuterEnumDefaultValue;
+                    break;
+                case r'outerEnumIntegerDefaultValue':
+                    result.outerEnumIntegerDefaultValue = serializers.deserialize(value,
+                        specifiedType: const FullType(OuterEnumIntegerDefaultValue)) as OuterEnumIntegerDefaultValue;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 
 class EnumTestEnumStringEnum extends EnumClass {

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/file_schema_test_class.dart

@@ -22,12 +22,64 @@ abstract class FileSchemaTestClass implements Built<FileSchemaTestClass, FileSch
     @BuiltValueField(wireName: r'files')
     BuiltList<ModelFile> get files;
 
-    // Boilerplate code needed to wire-up generated code
     FileSchemaTestClass._();
 
     static void _initializeBuilder(FileSchemaTestClassBuilder b) => b;
 
     factory FileSchemaTestClass([void updates(FileSchemaTestClassBuilder b)]) = _$FileSchemaTestClass;
-    static Serializer<FileSchemaTestClass> get serializer => _$fileSchemaTestClassSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<FileSchemaTestClass> get serializer => _$FileSchemaTestClassSerializer();
+}
+
+class _$FileSchemaTestClassSerializer implements StructuredSerializer<FileSchemaTestClass> {
+
+    @override
+    final Iterable<Type> types = const [FileSchemaTestClass, _$FileSchemaTestClass];
+    @override
+    final String wireName = r'FileSchemaTestClass';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, FileSchemaTestClass object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.file != null) {
+            result
+                ..add(r'file')
+                ..add(serializers.serialize(object.file,
+                    specifiedType: const FullType(ModelFile)));
+        }
+        if (object.files != null) {
+            result
+                ..add(r'files')
+                ..add(serializers.serialize(object.files,
+                    specifiedType: const FullType(BuiltList, [FullType(ModelFile)])));
+        }
+        return result;
+    }
+
+    @override
+    FileSchemaTestClass deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = FileSchemaTestClassBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'file':
+                    result.file.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(ModelFile)) as ModelFile);
+                    break;
+                case r'files':
+                    result.files.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltList, [FullType(ModelFile)])) as BuiltList<ModelFile>);
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/foo.dart

@@ -12,17 +12,58 @@ part 'foo.g.dart';
 
 abstract class Foo implements Built<Foo, FooBuilder> {
 
-    @nullable
     @BuiltValueField(wireName: r'bar')
     String get bar;
 
-    // Boilerplate code needed to wire-up generated code
     Foo._();
 
     static void _initializeBuilder(FooBuilder b) => b
         ..bar = 'bar';
 
     factory Foo([void updates(FooBuilder b)]) = _$Foo;
-    static Serializer<Foo> get serializer => _$fooSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<Foo> get serializer => _$FooSerializer();
+}
+
+class _$FooSerializer implements StructuredSerializer<Foo> {
+
+    @override
+    final Iterable<Type> types = const [Foo, _$Foo];
+    @override
+    final String wireName = r'Foo';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, Foo object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.bar != null) {
+            result
+                ..add(r'bar')
+                ..add(serializers.serialize(object.bar,
+                    specifiedType: const FullType(String)));
+        }
+        return result;
+    }
+
+    @override
+    Foo deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = FooBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'bar':
+                    result.bar = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/format_test.dart

@@ -25,7 +25,6 @@ abstract class FormatTest implements Built<FormatTest, FormatTestBuilder> {
     @BuiltValueField(wireName: r'int64')
     int get int64;
 
-    @nullable
     @BuiltValueField(wireName: r'number')
     num get number;
 
@@ -45,7 +44,6 @@ abstract class FormatTest implements Built<FormatTest, FormatTestBuilder> {
     @BuiltValueField(wireName: r'string')
     String get string;
 
-    @nullable
     @BuiltValueField(wireName: r'byte')
     String get byte;
 
@@ -53,7 +51,6 @@ abstract class FormatTest implements Built<FormatTest, FormatTestBuilder> {
     @BuiltValueField(wireName: r'binary')
     Uint8List get binary;
 
-    @nullable
     @BuiltValueField(wireName: r'date')
     DateTime get date;
 
@@ -65,7 +62,6 @@ abstract class FormatTest implements Built<FormatTest, FormatTestBuilder> {
     @BuiltValueField(wireName: r'uuid')
     String get uuid;
 
-    @nullable
     @BuiltValueField(wireName: r'password')
     String get password;
 
@@ -79,12 +75,196 @@ abstract class FormatTest implements Built<FormatTest, FormatTestBuilder> {
     @BuiltValueField(wireName: r'pattern_with_digits_and_delimiter')
     String get patternWithDigitsAndDelimiter;
 
-    // Boilerplate code needed to wire-up generated code
     FormatTest._();
 
     static void _initializeBuilder(FormatTestBuilder b) => b;
 
     factory FormatTest([void updates(FormatTestBuilder b)]) = _$FormatTest;
-    static Serializer<FormatTest> get serializer => _$formatTestSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<FormatTest> get serializer => _$FormatTestSerializer();
+}
+
+class _$FormatTestSerializer implements StructuredSerializer<FormatTest> {
+
+    @override
+    final Iterable<Type> types = const [FormatTest, _$FormatTest];
+    @override
+    final String wireName = r'FormatTest';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, FormatTest object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.integer != null) {
+            result
+                ..add(r'integer')
+                ..add(serializers.serialize(object.integer,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.int32 != null) {
+            result
+                ..add(r'int32')
+                ..add(serializers.serialize(object.int32,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.int64 != null) {
+            result
+                ..add(r'int64')
+                ..add(serializers.serialize(object.int64,
+                    specifiedType: const FullType(int)));
+        }
+        result
+            ..add(r'number')
+            ..add(serializers.serialize(object.number,
+                specifiedType: const FullType(num)));
+        if (object.float != null) {
+            result
+                ..add(r'float')
+                ..add(serializers.serialize(object.float,
+                    specifiedType: const FullType(double)));
+        }
+        if (object.double_ != null) {
+            result
+                ..add(r'double')
+                ..add(serializers.serialize(object.double_,
+                    specifiedType: const FullType(double)));
+        }
+        if (object.decimal != null) {
+            result
+                ..add(r'decimal')
+                ..add(serializers.serialize(object.decimal,
+                    specifiedType: const FullType(double)));
+        }
+        if (object.string != null) {
+            result
+                ..add(r'string')
+                ..add(serializers.serialize(object.string,
+                    specifiedType: const FullType(String)));
+        }
+        result
+            ..add(r'byte')
+            ..add(serializers.serialize(object.byte,
+                specifiedType: const FullType(String)));
+        if (object.binary != null) {
+            result
+                ..add(r'binary')
+                ..add(serializers.serialize(object.binary,
+                    specifiedType: const FullType(Uint8List)));
+        }
+        result
+            ..add(r'date')
+            ..add(serializers.serialize(object.date,
+                specifiedType: const FullType(DateTime)));
+        if (object.dateTime != null) {
+            result
+                ..add(r'dateTime')
+                ..add(serializers.serialize(object.dateTime,
+                    specifiedType: const FullType(DateTime)));
+        }
+        if (object.uuid != null) {
+            result
+                ..add(r'uuid')
+                ..add(serializers.serialize(object.uuid,
+                    specifiedType: const FullType(String)));
+        }
+        result
+            ..add(r'password')
+            ..add(serializers.serialize(object.password,
+                specifiedType: const FullType(String)));
+        if (object.patternWithDigits != null) {
+            result
+                ..add(r'pattern_with_digits')
+                ..add(serializers.serialize(object.patternWithDigits,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.patternWithDigitsAndDelimiter != null) {
+            result
+                ..add(r'pattern_with_digits_and_delimiter')
+                ..add(serializers.serialize(object.patternWithDigitsAndDelimiter,
+                    specifiedType: const FullType(String)));
+        }
+        return result;
+    }
+
+    @override
+    FormatTest deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = FormatTestBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'integer':
+                    result.integer = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'int32':
+                    result.int32 = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'int64':
+                    result.int64 = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'number':
+                    result.number = serializers.deserialize(value,
+                        specifiedType: const FullType(num)) as num;
+                    break;
+                case r'float':
+                    result.float = serializers.deserialize(value,
+                        specifiedType: const FullType(double)) as double;
+                    break;
+                case r'double':
+                    result.double_ = serializers.deserialize(value,
+                        specifiedType: const FullType(double)) as double;
+                    break;
+                case r'decimal':
+                    result.decimal = serializers.deserialize(value,
+                        specifiedType: const FullType(double)) as double;
+                    break;
+                case r'string':
+                    result.string = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'byte':
+                    result.byte = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'binary':
+                    result.binary = serializers.deserialize(value,
+                        specifiedType: const FullType(Uint8List)) as Uint8List;
+                    break;
+                case r'date':
+                    result.date = serializers.deserialize(value,
+                        specifiedType: const FullType(DateTime)) as DateTime;
+                    break;
+                case r'dateTime':
+                    result.dateTime = serializers.deserialize(value,
+                        specifiedType: const FullType(DateTime)) as DateTime;
+                    break;
+                case r'uuid':
+                    result.uuid = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'password':
+                    result.password = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'pattern_with_digits':
+                    result.patternWithDigits = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'pattern_with_digits_and_delimiter':
+                    result.patternWithDigitsAndDelimiter = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/has_only_read_only.dart

@@ -20,12 +20,64 @@ abstract class HasOnlyReadOnly implements Built<HasOnlyReadOnly, HasOnlyReadOnly
     @BuiltValueField(wireName: r'foo')
     String get foo;
 
-    // Boilerplate code needed to wire-up generated code
     HasOnlyReadOnly._();
 
     static void _initializeBuilder(HasOnlyReadOnlyBuilder b) => b;
 
     factory HasOnlyReadOnly([void updates(HasOnlyReadOnlyBuilder b)]) = _$HasOnlyReadOnly;
-    static Serializer<HasOnlyReadOnly> get serializer => _$hasOnlyReadOnlySerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<HasOnlyReadOnly> get serializer => _$HasOnlyReadOnlySerializer();
+}
+
+class _$HasOnlyReadOnlySerializer implements StructuredSerializer<HasOnlyReadOnly> {
+
+    @override
+    final Iterable<Type> types = const [HasOnlyReadOnly, _$HasOnlyReadOnly];
+    @override
+    final String wireName = r'HasOnlyReadOnly';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, HasOnlyReadOnly object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.bar != null) {
+            result
+                ..add(r'bar')
+                ..add(serializers.serialize(object.bar,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.foo != null) {
+            result
+                ..add(r'foo')
+                ..add(serializers.serialize(object.foo,
+                    specifiedType: const FullType(String)));
+        }
+        return result;
+    }
+
+    @override
+    HasOnlyReadOnly deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = HasOnlyReadOnlyBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'bar':
+                    result.bar = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'foo':
+                    result.foo = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/health_check_result.dart

@@ -16,12 +16,54 @@ abstract class HealthCheckResult implements Built<HealthCheckResult, HealthCheck
     @BuiltValueField(wireName: r'NullableMessage')
     String get nullableMessage;
 
-    // Boilerplate code needed to wire-up generated code
     HealthCheckResult._();
 
     static void _initializeBuilder(HealthCheckResultBuilder b) => b;
 
     factory HealthCheckResult([void updates(HealthCheckResultBuilder b)]) = _$HealthCheckResult;
-    static Serializer<HealthCheckResult> get serializer => _$healthCheckResultSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<HealthCheckResult> get serializer => _$HealthCheckResultSerializer();
+}
+
+class _$HealthCheckResultSerializer implements StructuredSerializer<HealthCheckResult> {
+
+    @override
+    final Iterable<Type> types = const [HealthCheckResult, _$HealthCheckResult];
+    @override
+    final String wireName = r'HealthCheckResult';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, HealthCheckResult object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.nullableMessage != null) {
+            result
+                ..add(r'NullableMessage')
+                ..add(serializers.serialize(object.nullableMessage,
+                    specifiedType: const FullType(String)));
+        }
+        return result;
+    }
+
+    @override
+    HealthCheckResult deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = HealthCheckResultBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'NullableMessage':
+                    result.nullableMessage = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/inline_response_default.dart

@@ -17,12 +17,54 @@ abstract class InlineResponseDefault implements Built<InlineResponseDefault, Inl
     @BuiltValueField(wireName: r'string')
     Foo get string;
 
-    // Boilerplate code needed to wire-up generated code
     InlineResponseDefault._();
 
     static void _initializeBuilder(InlineResponseDefaultBuilder b) => b;
 
     factory InlineResponseDefault([void updates(InlineResponseDefaultBuilder b)]) = _$InlineResponseDefault;
-    static Serializer<InlineResponseDefault> get serializer => _$inlineResponseDefaultSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<InlineResponseDefault> get serializer => _$InlineResponseDefaultSerializer();
+}
+
+class _$InlineResponseDefaultSerializer implements StructuredSerializer<InlineResponseDefault> {
+
+    @override
+    final Iterable<Type> types = const [InlineResponseDefault, _$InlineResponseDefault];
+    @override
+    final String wireName = r'InlineResponseDefault';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, InlineResponseDefault object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.string != null) {
+            result
+                ..add(r'string')
+                ..add(serializers.serialize(object.string,
+                    specifiedType: const FullType(Foo)));
+        }
+        return result;
+    }
+
+    @override
+    InlineResponseDefault deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = InlineResponseDefaultBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'string':
+                    result.string.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(Foo)) as Foo);
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/map_test.dart

@@ -30,13 +30,85 @@ abstract class MapTest implements Built<MapTest, MapTestBuilder> {
     @BuiltValueField(wireName: r'indirect_map')
     BuiltMap<String, bool> get indirectMap;
 
-    // Boilerplate code needed to wire-up generated code
     MapTest._();
 
     static void _initializeBuilder(MapTestBuilder b) => b;
 
     factory MapTest([void updates(MapTestBuilder b)]) = _$MapTest;
-    static Serializer<MapTest> get serializer => _$mapTestSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<MapTest> get serializer => _$MapTestSerializer();
+}
+
+class _$MapTestSerializer implements StructuredSerializer<MapTest> {
+
+    @override
+    final Iterable<Type> types = const [MapTest, _$MapTest];
+    @override
+    final String wireName = r'MapTest';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, MapTest object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.mapMapOfString != null) {
+            result
+                ..add(r'map_map_of_string')
+                ..add(serializers.serialize(object.mapMapOfString,
+                    specifiedType: const FullType(BuiltMap, [FullType(String), FullType(BuiltMap, [FullType(String), FullType(String)])])));
+        }
+        if (object.mapOfEnumString != null) {
+            result
+                ..add(r'map_of_enum_string')
+                ..add(serializers.serialize(object.mapOfEnumString,
+                    specifiedType: const FullType(BuiltMap, [FullType(String), FullType(MapTestMapOfEnumStringEnum)])));
+        }
+        if (object.directMap != null) {
+            result
+                ..add(r'direct_map')
+                ..add(serializers.serialize(object.directMap,
+                    specifiedType: const FullType(BuiltMap, [FullType(String), FullType(bool)])));
+        }
+        if (object.indirectMap != null) {
+            result
+                ..add(r'indirect_map')
+                ..add(serializers.serialize(object.indirectMap,
+                    specifiedType: const FullType(BuiltMap, [FullType(String), FullType(bool)])));
+        }
+        return result;
+    }
+
+    @override
+    MapTest deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = MapTestBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'map_map_of_string':
+                    result.mapMapOfString.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltMap, [FullType(String), FullType(BuiltMap, [FullType(String), FullType(String)])])) as BuiltMap<String, BuiltMap<String, String>>);
+                    break;
+                case r'map_of_enum_string':
+                    result.mapOfEnumString.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltMap, [FullType(String), FullType(MapTestMapOfEnumStringEnum)])) as BuiltMap<String, MapTestMapOfEnumStringEnum>);
+                    break;
+                case r'direct_map':
+                    result.directMap.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltMap, [FullType(String), FullType(bool)])) as BuiltMap<String, bool>);
+                    break;
+                case r'indirect_map':
+                    result.indirectMap.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltMap, [FullType(String), FullType(bool)])) as BuiltMap<String, bool>);
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 
 class MapTestMapOfEnumStringEnum extends EnumClass {

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/mixed_properties_and_additional_properties_class.dart

@@ -26,12 +26,74 @@ abstract class MixedPropertiesAndAdditionalPropertiesClass implements Built<Mixe
     @BuiltValueField(wireName: r'map')
     BuiltMap<String, Animal> get map;
 
-    // Boilerplate code needed to wire-up generated code
     MixedPropertiesAndAdditionalPropertiesClass._();
 
     static void _initializeBuilder(MixedPropertiesAndAdditionalPropertiesClassBuilder b) => b;
 
     factory MixedPropertiesAndAdditionalPropertiesClass([void updates(MixedPropertiesAndAdditionalPropertiesClassBuilder b)]) = _$MixedPropertiesAndAdditionalPropertiesClass;
-    static Serializer<MixedPropertiesAndAdditionalPropertiesClass> get serializer => _$mixedPropertiesAndAdditionalPropertiesClassSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<MixedPropertiesAndAdditionalPropertiesClass> get serializer => _$MixedPropertiesAndAdditionalPropertiesClassSerializer();
+}
+
+class _$MixedPropertiesAndAdditionalPropertiesClassSerializer implements StructuredSerializer<MixedPropertiesAndAdditionalPropertiesClass> {
+
+    @override
+    final Iterable<Type> types = const [MixedPropertiesAndAdditionalPropertiesClass, _$MixedPropertiesAndAdditionalPropertiesClass];
+    @override
+    final String wireName = r'MixedPropertiesAndAdditionalPropertiesClass';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, MixedPropertiesAndAdditionalPropertiesClass object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.uuid != null) {
+            result
+                ..add(r'uuid')
+                ..add(serializers.serialize(object.uuid,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.dateTime != null) {
+            result
+                ..add(r'dateTime')
+                ..add(serializers.serialize(object.dateTime,
+                    specifiedType: const FullType(DateTime)));
+        }
+        if (object.map != null) {
+            result
+                ..add(r'map')
+                ..add(serializers.serialize(object.map,
+                    specifiedType: const FullType(BuiltMap, [FullType(String), FullType(Animal)])));
+        }
+        return result;
+    }
+
+    @override
+    MixedPropertiesAndAdditionalPropertiesClass deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = MixedPropertiesAndAdditionalPropertiesClassBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'uuid':
+                    result.uuid = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'dateTime':
+                    result.dateTime = serializers.deserialize(value,
+                        specifiedType: const FullType(DateTime)) as DateTime;
+                    break;
+                case r'map':
+                    result.map.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltMap, [FullType(String), FullType(Animal)])) as BuiltMap<String, Animal>);
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/model200_response.dart

@@ -20,12 +20,64 @@ abstract class Model200Response implements Built<Model200Response, Model200Respo
     @BuiltValueField(wireName: r'class')
     String get class_;
 
-    // Boilerplate code needed to wire-up generated code
     Model200Response._();
 
     static void _initializeBuilder(Model200ResponseBuilder b) => b;
 
     factory Model200Response([void updates(Model200ResponseBuilder b)]) = _$Model200Response;
-    static Serializer<Model200Response> get serializer => _$model200ResponseSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<Model200Response> get serializer => _$Model200ResponseSerializer();
+}
+
+class _$Model200ResponseSerializer implements StructuredSerializer<Model200Response> {
+
+    @override
+    final Iterable<Type> types = const [Model200Response, _$Model200Response];
+    @override
+    final String wireName = r'Model200Response';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, Model200Response object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.name != null) {
+            result
+                ..add(r'name')
+                ..add(serializers.serialize(object.name,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.class_ != null) {
+            result
+                ..add(r'class')
+                ..add(serializers.serialize(object.class_,
+                    specifiedType: const FullType(String)));
+        }
+        return result;
+    }
+
+    @override
+    Model200Response deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = Model200ResponseBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'name':
+                    result.name = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'class':
+                    result.class_ = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/model_client.dart

@@ -16,12 +16,54 @@ abstract class ModelClient implements Built<ModelClient, ModelClientBuilder> {
     @BuiltValueField(wireName: r'client')
     String get client;
 
-    // Boilerplate code needed to wire-up generated code
     ModelClient._();
 
     static void _initializeBuilder(ModelClientBuilder b) => b;
 
     factory ModelClient([void updates(ModelClientBuilder b)]) = _$ModelClient;
-    static Serializer<ModelClient> get serializer => _$modelClientSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<ModelClient> get serializer => _$ModelClientSerializer();
+}
+
+class _$ModelClientSerializer implements StructuredSerializer<ModelClient> {
+
+    @override
+    final Iterable<Type> types = const [ModelClient, _$ModelClient];
+    @override
+    final String wireName = r'ModelClient';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, ModelClient object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.client != null) {
+            result
+                ..add(r'client')
+                ..add(serializers.serialize(object.client,
+                    specifiedType: const FullType(String)));
+        }
+        return result;
+    }
+
+    @override
+    ModelClient deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = ModelClientBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'client':
+                    result.client = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/model_file.dart

@@ -17,12 +17,54 @@ abstract class ModelFile implements Built<ModelFile, ModelFileBuilder> {
     @BuiltValueField(wireName: r'sourceURI')
     String get sourceURI;
 
-    // Boilerplate code needed to wire-up generated code
     ModelFile._();
 
     static void _initializeBuilder(ModelFileBuilder b) => b;
 
     factory ModelFile([void updates(ModelFileBuilder b)]) = _$ModelFile;
-    static Serializer<ModelFile> get serializer => _$modelFileSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<ModelFile> get serializer => _$ModelFileSerializer();
+}
+
+class _$ModelFileSerializer implements StructuredSerializer<ModelFile> {
+
+    @override
+    final Iterable<Type> types = const [ModelFile, _$ModelFile];
+    @override
+    final String wireName = r'ModelFile';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, ModelFile object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.sourceURI != null) {
+            result
+                ..add(r'sourceURI')
+                ..add(serializers.serialize(object.sourceURI,
+                    specifiedType: const FullType(String)));
+        }
+        return result;
+    }
+
+    @override
+    ModelFile deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = ModelFileBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'sourceURI':
+                    result.sourceURI = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/model_list.dart

@@ -16,12 +16,54 @@ abstract class ModelList implements Built<ModelList, ModelListBuilder> {
     @BuiltValueField(wireName: r'123-list')
     String get n123list;
 
-    // Boilerplate code needed to wire-up generated code
     ModelList._();
 
     static void _initializeBuilder(ModelListBuilder b) => b;
 
     factory ModelList([void updates(ModelListBuilder b)]) = _$ModelList;
-    static Serializer<ModelList> get serializer => _$modelListSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<ModelList> get serializer => _$ModelListSerializer();
+}
+
+class _$ModelListSerializer implements StructuredSerializer<ModelList> {
+
+    @override
+    final Iterable<Type> types = const [ModelList, _$ModelList];
+    @override
+    final String wireName = r'ModelList';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, ModelList object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.n123list != null) {
+            result
+                ..add(r'123-list')
+                ..add(serializers.serialize(object.n123list,
+                    specifiedType: const FullType(String)));
+        }
+        return result;
+    }
+
+    @override
+    ModelList deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = ModelListBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'123-list':
+                    result.n123list = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/model_return.dart

@@ -16,12 +16,54 @@ abstract class ModelReturn implements Built<ModelReturn, ModelReturnBuilder> {
     @BuiltValueField(wireName: r'return')
     int get return_;
 
-    // Boilerplate code needed to wire-up generated code
     ModelReturn._();
 
     static void _initializeBuilder(ModelReturnBuilder b) => b;
 
     factory ModelReturn([void updates(ModelReturnBuilder b)]) = _$ModelReturn;
-    static Serializer<ModelReturn> get serializer => _$modelReturnSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<ModelReturn> get serializer => _$ModelReturnSerializer();
+}
+
+class _$ModelReturnSerializer implements StructuredSerializer<ModelReturn> {
+
+    @override
+    final Iterable<Type> types = const [ModelReturn, _$ModelReturn];
+    @override
+    final String wireName = r'ModelReturn';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, ModelReturn object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.return_ != null) {
+            result
+                ..add(r'return')
+                ..add(serializers.serialize(object.return_,
+                    specifiedType: const FullType(int)));
+        }
+        return result;
+    }
+
+    @override
+    ModelReturn deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = ModelReturnBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'return':
+                    result.return_ = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/name.dart

@@ -12,7 +12,6 @@ part 'name.g.dart';
 
 abstract class Name implements Built<Name, NameBuilder> {
 
-    @nullable
     @BuiltValueField(wireName: r'name')
     int get name;
 
@@ -28,12 +27,82 @@ abstract class Name implements Built<Name, NameBuilder> {
     @BuiltValueField(wireName: r'123Number')
     int get n123number;
 
-    // Boilerplate code needed to wire-up generated code
     Name._();
 
     static void _initializeBuilder(NameBuilder b) => b;
 
     factory Name([void updates(NameBuilder b)]) = _$Name;
-    static Serializer<Name> get serializer => _$nameSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<Name> get serializer => _$NameSerializer();
+}
+
+class _$NameSerializer implements StructuredSerializer<Name> {
+
+    @override
+    final Iterable<Type> types = const [Name, _$Name];
+    @override
+    final String wireName = r'Name';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, Name object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        result
+            ..add(r'name')
+            ..add(serializers.serialize(object.name,
+                specifiedType: const FullType(int)));
+        if (object.snakeCase != null) {
+            result
+                ..add(r'snake_case')
+                ..add(serializers.serialize(object.snakeCase,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.property != null) {
+            result
+                ..add(r'property')
+                ..add(serializers.serialize(object.property,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.n123number != null) {
+            result
+                ..add(r'123Number')
+                ..add(serializers.serialize(object.n123number,
+                    specifiedType: const FullType(int)));
+        }
+        return result;
+    }
+
+    @override
+    Name deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = NameBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'name':
+                    result.name = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'snake_case':
+                    result.snakeCase = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'property':
+                    result.property = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'123Number':
+                    result.n123number = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/nullable_class.dart

@@ -62,12 +62,164 @@ abstract class NullableClass implements Built<NullableClass, NullableClassBuilde
     @BuiltValueField(wireName: r'object_items_nullable')
     BuiltMap<String, JsonObject> get objectItemsNullable;
 
-    // Boilerplate code needed to wire-up generated code
     NullableClass._();
 
     static void _initializeBuilder(NullableClassBuilder b) => b;
 
     factory NullableClass([void updates(NullableClassBuilder b)]) = _$NullableClass;
-    static Serializer<NullableClass> get serializer => _$nullableClassSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<NullableClass> get serializer => _$NullableClassSerializer();
+}
+
+class _$NullableClassSerializer implements StructuredSerializer<NullableClass> {
+
+    @override
+    final Iterable<Type> types = const [NullableClass, _$NullableClass];
+    @override
+    final String wireName = r'NullableClass';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, NullableClass object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.integerProp != null) {
+            result
+                ..add(r'integer_prop')
+                ..add(serializers.serialize(object.integerProp,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.numberProp != null) {
+            result
+                ..add(r'number_prop')
+                ..add(serializers.serialize(object.numberProp,
+                    specifiedType: const FullType(num)));
+        }
+        if (object.booleanProp != null) {
+            result
+                ..add(r'boolean_prop')
+                ..add(serializers.serialize(object.booleanProp,
+                    specifiedType: const FullType(bool)));
+        }
+        if (object.stringProp != null) {
+            result
+                ..add(r'string_prop')
+                ..add(serializers.serialize(object.stringProp,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.dateProp != null) {
+            result
+                ..add(r'date_prop')
+                ..add(serializers.serialize(object.dateProp,
+                    specifiedType: const FullType(DateTime)));
+        }
+        if (object.datetimeProp != null) {
+            result
+                ..add(r'datetime_prop')
+                ..add(serializers.serialize(object.datetimeProp,
+                    specifiedType: const FullType(DateTime)));
+        }
+        if (object.arrayNullableProp != null) {
+            result
+                ..add(r'array_nullable_prop')
+                ..add(serializers.serialize(object.arrayNullableProp,
+                    specifiedType: const FullType(BuiltList, [FullType(JsonObject)])));
+        }
+        if (object.arrayAndItemsNullableProp != null) {
+            result
+                ..add(r'array_and_items_nullable_prop')
+                ..add(serializers.serialize(object.arrayAndItemsNullableProp,
+                    specifiedType: const FullType(BuiltList, [FullType(JsonObject)])));
+        }
+        if (object.arrayItemsNullable != null) {
+            result
+                ..add(r'array_items_nullable')
+                ..add(serializers.serialize(object.arrayItemsNullable,
+                    specifiedType: const FullType(BuiltList, [FullType(JsonObject)])));
+        }
+        if (object.objectNullableProp != null) {
+            result
+                ..add(r'object_nullable_prop')
+                ..add(serializers.serialize(object.objectNullableProp,
+                    specifiedType: const FullType(BuiltMap, [FullType(String), FullType(JsonObject)])));
+        }
+        if (object.objectAndItemsNullableProp != null) {
+            result
+                ..add(r'object_and_items_nullable_prop')
+                ..add(serializers.serialize(object.objectAndItemsNullableProp,
+                    specifiedType: const FullType(BuiltMap, [FullType(String), FullType(JsonObject)])));
+        }
+        if (object.objectItemsNullable != null) {
+            result
+                ..add(r'object_items_nullable')
+                ..add(serializers.serialize(object.objectItemsNullable,
+                    specifiedType: const FullType(BuiltMap, [FullType(String), FullType(JsonObject)])));
+        }
+        return result;
+    }
+
+    @override
+    NullableClass deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = NullableClassBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'integer_prop':
+                    result.integerProp = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'number_prop':
+                    result.numberProp = serializers.deserialize(value,
+                        specifiedType: const FullType(num)) as num;
+                    break;
+                case r'boolean_prop':
+                    result.booleanProp = serializers.deserialize(value,
+                        specifiedType: const FullType(bool)) as bool;
+                    break;
+                case r'string_prop':
+                    result.stringProp = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'date_prop':
+                    result.dateProp = serializers.deserialize(value,
+                        specifiedType: const FullType(DateTime)) as DateTime;
+                    break;
+                case r'datetime_prop':
+                    result.datetimeProp = serializers.deserialize(value,
+                        specifiedType: const FullType(DateTime)) as DateTime;
+                    break;
+                case r'array_nullable_prop':
+                    result.arrayNullableProp.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltList, [FullType(JsonObject)])) as BuiltList<JsonObject>);
+                    break;
+                case r'array_and_items_nullable_prop':
+                    result.arrayAndItemsNullableProp.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltList, [FullType(JsonObject)])) as BuiltList<JsonObject>);
+                    break;
+                case r'array_items_nullable':
+                    result.arrayItemsNullable.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltList, [FullType(JsonObject)])) as BuiltList<JsonObject>);
+                    break;
+                case r'object_nullable_prop':
+                    result.objectNullableProp.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltMap, [FullType(String), FullType(JsonObject)])) as BuiltMap<String, JsonObject>);
+                    break;
+                case r'object_and_items_nullable_prop':
+                    result.objectAndItemsNullableProp.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltMap, [FullType(String), FullType(JsonObject)])) as BuiltMap<String, JsonObject>);
+                    break;
+                case r'object_items_nullable':
+                    result.objectItemsNullable.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltMap, [FullType(String), FullType(JsonObject)])) as BuiltMap<String, JsonObject>);
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/number_only.dart

@@ -16,12 +16,54 @@ abstract class NumberOnly implements Built<NumberOnly, NumberOnlyBuilder> {
     @BuiltValueField(wireName: r'JustNumber')
     num get justNumber;
 
-    // Boilerplate code needed to wire-up generated code
     NumberOnly._();
 
     static void _initializeBuilder(NumberOnlyBuilder b) => b;
 
     factory NumberOnly([void updates(NumberOnlyBuilder b)]) = _$NumberOnly;
-    static Serializer<NumberOnly> get serializer => _$numberOnlySerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<NumberOnly> get serializer => _$NumberOnlySerializer();
+}
+
+class _$NumberOnlySerializer implements StructuredSerializer<NumberOnly> {
+
+    @override
+    final Iterable<Type> types = const [NumberOnly, _$NumberOnly];
+    @override
+    final String wireName = r'NumberOnly';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, NumberOnly object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.justNumber != null) {
+            result
+                ..add(r'JustNumber')
+                ..add(serializers.serialize(object.justNumber,
+                    specifiedType: const FullType(num)));
+        }
+        return result;
+    }
+
+    @override
+    NumberOnly deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = NumberOnlyBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'JustNumber':
+                    result.justNumber = serializers.deserialize(value,
+                        specifiedType: const FullType(num)) as num;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/order.dart

@@ -35,18 +35,109 @@ abstract class Order implements Built<Order, OrderBuilder> {
     OrderStatusEnum get status;
     // enum statusEnum {  placed,  approved,  delivered,  };
 
-    @nullable
     @BuiltValueField(wireName: r'complete')
     bool get complete;
 
-    // Boilerplate code needed to wire-up generated code
     Order._();
 
     static void _initializeBuilder(OrderBuilder b) => b
         ..complete = false;
 
     factory Order([void updates(OrderBuilder b)]) = _$Order;
-    static Serializer<Order> get serializer => _$orderSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<Order> get serializer => _$OrderSerializer();
+}
+
+class _$OrderSerializer implements StructuredSerializer<Order> {
+
+    @override
+    final Iterable<Type> types = const [Order, _$Order];
+    @override
+    final String wireName = r'Order';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, Order object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.id != null) {
+            result
+                ..add(r'id')
+                ..add(serializers.serialize(object.id,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.petId != null) {
+            result
+                ..add(r'petId')
+                ..add(serializers.serialize(object.petId,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.quantity != null) {
+            result
+                ..add(r'quantity')
+                ..add(serializers.serialize(object.quantity,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.shipDate != null) {
+            result
+                ..add(r'shipDate')
+                ..add(serializers.serialize(object.shipDate,
+                    specifiedType: const FullType(DateTime)));
+        }
+        if (object.status != null) {
+            result
+                ..add(r'status')
+                ..add(serializers.serialize(object.status,
+                    specifiedType: const FullType(OrderStatusEnum)));
+        }
+        if (object.complete != null) {
+            result
+                ..add(r'complete')
+                ..add(serializers.serialize(object.complete,
+                    specifiedType: const FullType(bool)));
+        }
+        return result;
+    }
+
+    @override
+    Order deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = OrderBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'id':
+                    result.id = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'petId':
+                    result.petId = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'quantity':
+                    result.quantity = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'shipDate':
+                    result.shipDate = serializers.deserialize(value,
+                        specifiedType: const FullType(DateTime)) as DateTime;
+                    break;
+                case r'status':
+                    result.status = serializers.deserialize(value,
+                        specifiedType: const FullType(OrderStatusEnum)) as OrderStatusEnum;
+                    break;
+                case r'complete':
+                    result.complete = serializers.deserialize(value,
+                        specifiedType: const FullType(bool)) as bool;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 
 class OrderStatusEnum extends EnumClass {

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/outer_composite.dart

@@ -24,12 +24,74 @@ abstract class OuterComposite implements Built<OuterComposite, OuterCompositeBui
     @BuiltValueField(wireName: r'my_boolean')
     bool get myBoolean;
 
-    // Boilerplate code needed to wire-up generated code
     OuterComposite._();
 
     static void _initializeBuilder(OuterCompositeBuilder b) => b;
 
     factory OuterComposite([void updates(OuterCompositeBuilder b)]) = _$OuterComposite;
-    static Serializer<OuterComposite> get serializer => _$outerCompositeSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<OuterComposite> get serializer => _$OuterCompositeSerializer();
+}
+
+class _$OuterCompositeSerializer implements StructuredSerializer<OuterComposite> {
+
+    @override
+    final Iterable<Type> types = const [OuterComposite, _$OuterComposite];
+    @override
+    final String wireName = r'OuterComposite';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, OuterComposite object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.myNumber != null) {
+            result
+                ..add(r'my_number')
+                ..add(serializers.serialize(object.myNumber,
+                    specifiedType: const FullType(num)));
+        }
+        if (object.myString != null) {
+            result
+                ..add(r'my_string')
+                ..add(serializers.serialize(object.myString,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.myBoolean != null) {
+            result
+                ..add(r'my_boolean')
+                ..add(serializers.serialize(object.myBoolean,
+                    specifiedType: const FullType(bool)));
+        }
+        return result;
+    }
+
+    @override
+    OuterComposite deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = OuterCompositeBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'my_number':
+                    result.myNumber = serializers.deserialize(value,
+                        specifiedType: const FullType(num)) as num;
+                    break;
+                case r'my_string':
+                    result.myString = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'my_boolean':
+                    result.myBoolean = serializers.deserialize(value,
+                        specifiedType: const FullType(bool)) as bool;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/pet.dart

@@ -23,11 +23,9 @@ abstract class Pet implements Built<Pet, PetBuilder> {
     @BuiltValueField(wireName: r'category')
     Category get category;
 
-    @nullable
     @BuiltValueField(wireName: r'name')
     String get name;
 
-    @nullable
     @BuiltValueField(wireName: r'photoUrls')
     BuiltSet<String> get photoUrls;
 
@@ -41,13 +39,101 @@ abstract class Pet implements Built<Pet, PetBuilder> {
     PetStatusEnum get status;
     // enum statusEnum {  available,  pending,  sold,  };
 
-    // Boilerplate code needed to wire-up generated code
     Pet._();
 
     static void _initializeBuilder(PetBuilder b) => b;
 
     factory Pet([void updates(PetBuilder b)]) = _$Pet;
-    static Serializer<Pet> get serializer => _$petSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<Pet> get serializer => _$PetSerializer();
+}
+
+class _$PetSerializer implements StructuredSerializer<Pet> {
+
+    @override
+    final Iterable<Type> types = const [Pet, _$Pet];
+    @override
+    final String wireName = r'Pet';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, Pet object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.id != null) {
+            result
+                ..add(r'id')
+                ..add(serializers.serialize(object.id,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.category != null) {
+            result
+                ..add(r'category')
+                ..add(serializers.serialize(object.category,
+                    specifiedType: const FullType(Category)));
+        }
+        result
+            ..add(r'name')
+            ..add(serializers.serialize(object.name,
+                specifiedType: const FullType(String)));
+        result
+            ..add(r'photoUrls')
+            ..add(serializers.serialize(object.photoUrls,
+                specifiedType: const FullType(BuiltSet, [FullType(String)])));
+        if (object.tags != null) {
+            result
+                ..add(r'tags')
+                ..add(serializers.serialize(object.tags,
+                    specifiedType: const FullType(BuiltList, [FullType(Tag)])));
+        }
+        if (object.status != null) {
+            result
+                ..add(r'status')
+                ..add(serializers.serialize(object.status,
+                    specifiedType: const FullType(PetStatusEnum)));
+        }
+        return result;
+    }
+
+    @override
+    Pet deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = PetBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'id':
+                    result.id = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'category':
+                    result.category.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(Category)) as Category);
+                    break;
+                case r'name':
+                    result.name = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'photoUrls':
+                    result.photoUrls.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltSet, [FullType(String)])) as BuiltSet<String>);
+                    break;
+                case r'tags':
+                    result.tags.replace(serializers.deserialize(value,
+                        specifiedType: const FullType(BuiltList, [FullType(Tag)])) as BuiltList<Tag>);
+                    break;
+                case r'status':
+                    result.status = serializers.deserialize(value,
+                        specifiedType: const FullType(PetStatusEnum)) as PetStatusEnum;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 
 class PetStatusEnum extends EnumClass {

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/read_only_first.dart

@@ -20,12 +20,64 @@ abstract class ReadOnlyFirst implements Built<ReadOnlyFirst, ReadOnlyFirstBuilde
     @BuiltValueField(wireName: r'baz')
     String get baz;
 
-    // Boilerplate code needed to wire-up generated code
     ReadOnlyFirst._();
 
     static void _initializeBuilder(ReadOnlyFirstBuilder b) => b;
 
     factory ReadOnlyFirst([void updates(ReadOnlyFirstBuilder b)]) = _$ReadOnlyFirst;
-    static Serializer<ReadOnlyFirst> get serializer => _$readOnlyFirstSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<ReadOnlyFirst> get serializer => _$ReadOnlyFirstSerializer();
+}
+
+class _$ReadOnlyFirstSerializer implements StructuredSerializer<ReadOnlyFirst> {
+
+    @override
+    final Iterable<Type> types = const [ReadOnlyFirst, _$ReadOnlyFirst];
+    @override
+    final String wireName = r'ReadOnlyFirst';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, ReadOnlyFirst object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.bar != null) {
+            result
+                ..add(r'bar')
+                ..add(serializers.serialize(object.bar,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.baz != null) {
+            result
+                ..add(r'baz')
+                ..add(serializers.serialize(object.baz,
+                    specifiedType: const FullType(String)));
+        }
+        return result;
+    }
+
+    @override
+    ReadOnlyFirst deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = ReadOnlyFirstBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'bar':
+                    result.bar = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'baz':
+                    result.baz = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/special_model_name.dart

@@ -16,12 +16,54 @@ abstract class SpecialModelName implements Built<SpecialModelName, SpecialModelN
     @BuiltValueField(wireName: r'$special[property.name]')
     int get dollarSpecialLeftSquareBracketPropertyPeriodNameRightSquareBracket;
 
-    // Boilerplate code needed to wire-up generated code
     SpecialModelName._();
 
     static void _initializeBuilder(SpecialModelNameBuilder b) => b;
 
     factory SpecialModelName([void updates(SpecialModelNameBuilder b)]) = _$SpecialModelName;
-    static Serializer<SpecialModelName> get serializer => _$specialModelNameSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<SpecialModelName> get serializer => _$SpecialModelNameSerializer();
+}
+
+class _$SpecialModelNameSerializer implements StructuredSerializer<SpecialModelName> {
+
+    @override
+    final Iterable<Type> types = const [SpecialModelName, _$SpecialModelName];
+    @override
+    final String wireName = r'SpecialModelName';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, SpecialModelName object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.dollarSpecialLeftSquareBracketPropertyPeriodNameRightSquareBracket != null) {
+            result
+                ..add(r'$special[property.name]')
+                ..add(serializers.serialize(object.dollarSpecialLeftSquareBracketPropertyPeriodNameRightSquareBracket,
+                    specifiedType: const FullType(int)));
+        }
+        return result;
+    }
+
+    @override
+    SpecialModelName deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = SpecialModelNameBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'$special[property.name]':
+                    result.dollarSpecialLeftSquareBracketPropertyPeriodNameRightSquareBracket = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/tag.dart

@@ -20,12 +20,64 @@ abstract class Tag implements Built<Tag, TagBuilder> {
     @BuiltValueField(wireName: r'name')
     String get name;
 
-    // Boilerplate code needed to wire-up generated code
     Tag._();
 
     static void _initializeBuilder(TagBuilder b) => b;
 
     factory Tag([void updates(TagBuilder b)]) = _$Tag;
-    static Serializer<Tag> get serializer => _$tagSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<Tag> get serializer => _$TagSerializer();
+}
+
+class _$TagSerializer implements StructuredSerializer<Tag> {
+
+    @override
+    final Iterable<Type> types = const [Tag, _$Tag];
+    @override
+    final String wireName = r'Tag';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, Tag object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.id != null) {
+            result
+                ..add(r'id')
+                ..add(serializers.serialize(object.id,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.name != null) {
+            result
+                ..add(r'name')
+                ..add(serializers.serialize(object.name,
+                    specifiedType: const FullType(String)));
+        }
+        return result;
+    }
+
+    @override
+    Tag deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = TagBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'id':
+                    result.id = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'name':
+                    result.name = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/lib/model/user.dart

@@ -45,12 +45,124 @@ abstract class User implements Built<User, UserBuilder> {
     @BuiltValueField(wireName: r'userStatus')
     int get userStatus;
 
-    // Boilerplate code needed to wire-up generated code
     User._();
 
     static void _initializeBuilder(UserBuilder b) => b;
 
     factory User([void updates(UserBuilder b)]) = _$User;
-    static Serializer<User> get serializer => _$userSerializer;
+
+    @BuiltValueSerializer(custom: true)
+    static Serializer<User> get serializer => _$UserSerializer();
+}
+
+class _$UserSerializer implements StructuredSerializer<User> {
+
+    @override
+    final Iterable<Type> types = const [User, _$User];
+    @override
+    final String wireName = r'User';
+
+    @override
+    Iterable<Object> serialize(Serializers serializers, User object,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = <Object>[];
+        if (object.id != null) {
+            result
+                ..add(r'id')
+                ..add(serializers.serialize(object.id,
+                    specifiedType: const FullType(int)));
+        }
+        if (object.username != null) {
+            result
+                ..add(r'username')
+                ..add(serializers.serialize(object.username,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.firstName != null) {
+            result
+                ..add(r'firstName')
+                ..add(serializers.serialize(object.firstName,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.lastName != null) {
+            result
+                ..add(r'lastName')
+                ..add(serializers.serialize(object.lastName,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.email != null) {
+            result
+                ..add(r'email')
+                ..add(serializers.serialize(object.email,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.password != null) {
+            result
+                ..add(r'password')
+                ..add(serializers.serialize(object.password,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.phone != null) {
+            result
+                ..add(r'phone')
+                ..add(serializers.serialize(object.phone,
+                    specifiedType: const FullType(String)));
+        }
+        if (object.userStatus != null) {
+            result
+                ..add(r'userStatus')
+                ..add(serializers.serialize(object.userStatus,
+                    specifiedType: const FullType(int)));
+        }
+        return result;
+    }
+
+    @override
+    User deserialize(Serializers serializers, Iterable<Object> serialized,
+        {FullType specifiedType = FullType.unspecified}) {
+        final result = UserBuilder();
+
+        final iterator = serialized.iterator;
+        while (iterator.moveNext()) {
+            final key = iterator.current as String;
+            iterator.moveNext();
+            final dynamic value = iterator.current;
+            switch (key) {
+                case r'id':
+                    result.id = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+                case r'username':
+                    result.username = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'firstName':
+                    result.firstName = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'lastName':
+                    result.lastName = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'email':
+                    result.email = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'password':
+                    result.password = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'phone':
+                    result.phone = serializers.deserialize(value,
+                        specifiedType: const FullType(String)) as String;
+                    break;
+                case r'userStatus':
+                    result.userStatus = serializers.deserialize(value,
+                        specifiedType: const FullType(int)) as int;
+                    break;
+            }
+        }
+        return result.build();
+    }
 }
 

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/additional_properties_class_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for AdditionalPropertiesClass
 void main() {
-  final instance = AdditionalPropertiesClass();
+  final instance = AdditionalPropertiesClassBuilder();
+  // TODO add properties to the builder and call build()
 
   group(AdditionalPropertiesClass, () {
     // BuiltMap<String, String> mapProperty

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/animal_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for Animal
 void main() {
-  final instance = Animal();
+  final instance = AnimalBuilder();
+  // TODO add properties to the builder and call build()
 
   group(Animal, () {
     // String className

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/api_response_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for ApiResponse
 void main() {
-  final instance = ApiResponse();
+  final instance = ApiResponseBuilder();
+  // TODO add properties to the builder and call build()
 
   group(ApiResponse, () {
     // int code

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/array_of_array_of_number_only_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for ArrayOfArrayOfNumberOnly
 void main() {
-  final instance = ArrayOfArrayOfNumberOnly();
+  final instance = ArrayOfArrayOfNumberOnlyBuilder();
+  // TODO add properties to the builder and call build()
 
   group(ArrayOfArrayOfNumberOnly, () {
     // BuiltList<BuiltList<num>> arrayArrayNumber

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/array_of_number_only_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for ArrayOfNumberOnly
 void main() {
-  final instance = ArrayOfNumberOnly();
+  final instance = ArrayOfNumberOnlyBuilder();
+  // TODO add properties to the builder and call build()
 
   group(ArrayOfNumberOnly, () {
     // BuiltList<num> arrayNumber

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/array_test_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for ArrayTest
 void main() {
-  final instance = ArrayTest();
+  final instance = ArrayTestBuilder();
+  // TODO add properties to the builder and call build()
 
   group(ArrayTest, () {
     // BuiltList<String> arrayOfString

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/capitalization_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for Capitalization
 void main() {
-  final instance = Capitalization();
+  final instance = CapitalizationBuilder();
+  // TODO add properties to the builder and call build()
 
   group(Capitalization, () {
     // String smallCamel

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/cat_all_of_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for CatAllOf
 void main() {
-  final instance = CatAllOf();
+  final instance = CatAllOfBuilder();
+  // TODO add properties to the builder and call build()
 
   group(CatAllOf, () {
     // bool declawed

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/cat_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for Cat
 void main() {
-  final instance = Cat();
+  final instance = CatBuilder();
+  // TODO add properties to the builder and call build()
 
   group(Cat, () {
     // String className

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/category_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for Category
 void main() {
-  final instance = Category();
+  final instance = CategoryBuilder();
+  // TODO add properties to the builder and call build()
 
   group(Category, () {
     // int id

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/class_model_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for ClassModel
 void main() {
-  final instance = ClassModel();
+  final instance = ClassModelBuilder();
+  // TODO add properties to the builder and call build()
 
   group(ClassModel, () {
     // String class_

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/dog_all_of_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for DogAllOf
 void main() {
-  final instance = DogAllOf();
+  final instance = DogAllOfBuilder();
+  // TODO add properties to the builder and call build()
 
   group(DogAllOf, () {
     // String breed

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/dog_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for Dog
 void main() {
-  final instance = Dog();
+  final instance = DogBuilder();
+  // TODO add properties to the builder and call build()
 
   group(Dog, () {
     // String className

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/enum_arrays_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for EnumArrays
 void main() {
-  final instance = EnumArrays();
+  final instance = EnumArraysBuilder();
+  // TODO add properties to the builder and call build()
 
   group(EnumArrays, () {
     // String justSymbol

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/enum_test_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for EnumTest
 void main() {
-  final instance = EnumTest();
+  final instance = EnumTestBuilder();
+  // TODO add properties to the builder and call build()
 
   group(EnumTest, () {
     // String enumString

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/file_schema_test_class_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for FileSchemaTestClass
 void main() {
-  final instance = FileSchemaTestClass();
+  final instance = FileSchemaTestClassBuilder();
+  // TODO add properties to the builder and call build()
 
   group(FileSchemaTestClass, () {
     // ModelFile file

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/foo_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for Foo
 void main() {
-  final instance = Foo();
+  final instance = FooBuilder();
+  // TODO add properties to the builder and call build()
 
   group(Foo, () {
     // String bar (default value: 'bar')

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/format_test_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for FormatTest
 void main() {
-  final instance = FormatTest();
+  final instance = FormatTestBuilder();
+  // TODO add properties to the builder and call build()
 
   group(FormatTest, () {
     // int integer

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/has_only_read_only_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for HasOnlyReadOnly
 void main() {
-  final instance = HasOnlyReadOnly();
+  final instance = HasOnlyReadOnlyBuilder();
+  // TODO add properties to the builder and call build()
 
   group(HasOnlyReadOnly, () {
     // String bar

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/health_check_result_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for HealthCheckResult
 void main() {
-  final instance = HealthCheckResult();
+  final instance = HealthCheckResultBuilder();
+  // TODO add properties to the builder and call build()
 
   group(HealthCheckResult, () {
     // String nullableMessage

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/inline_response_default_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for InlineResponseDefault
 void main() {
-  final instance = InlineResponseDefault();
+  final instance = InlineResponseDefaultBuilder();
+  // TODO add properties to the builder and call build()
 
   group(InlineResponseDefault, () {
     // Foo string

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/map_test_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for MapTest
 void main() {
-  final instance = MapTest();
+  final instance = MapTestBuilder();
+  // TODO add properties to the builder and call build()
 
   group(MapTest, () {
     // BuiltMap<String, BuiltMap<String, String>> mapMapOfString

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/mixed_properties_and_additional_properties_class_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for MixedPropertiesAndAdditionalPropertiesClass
 void main() {
-  final instance = MixedPropertiesAndAdditionalPropertiesClass();
+  final instance = MixedPropertiesAndAdditionalPropertiesClassBuilder();
+  // TODO add properties to the builder and call build()
 
   group(MixedPropertiesAndAdditionalPropertiesClass, () {
     // String uuid

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/model200_response_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for Model200Response
 void main() {
-  final instance = Model200Response();
+  final instance = Model200ResponseBuilder();
+  // TODO add properties to the builder and call build()
 
   group(Model200Response, () {
     // int name

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/model_client_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for ModelClient
 void main() {
-  final instance = ModelClient();
+  final instance = ModelClientBuilder();
+  // TODO add properties to the builder and call build()
 
   group(ModelClient, () {
     // String client

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/model_file_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for ModelFile
 void main() {
-  final instance = ModelFile();
+  final instance = ModelFileBuilder();
+  // TODO add properties to the builder and call build()
 
   group(ModelFile, () {
     // Test capitalization

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/model_list_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for ModelList
 void main() {
-  final instance = ModelList();
+  final instance = ModelListBuilder();
+  // TODO add properties to the builder and call build()
 
   group(ModelList, () {
     // String n123list

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/model_return_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for ModelReturn
 void main() {
-  final instance = ModelReturn();
+  final instance = ModelReturnBuilder();
+  // TODO add properties to the builder and call build()
 
   group(ModelReturn, () {
     // int return_

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/name_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for Name
 void main() {
-  final instance = Name();
+  final instance = NameBuilder();
+  // TODO add properties to the builder and call build()
 
   group(Name, () {
     // int name

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/nullable_class_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for NullableClass
 void main() {
-  final instance = NullableClass();
+  final instance = NullableClassBuilder();
+  // TODO add properties to the builder and call build()
 
   group(NullableClass, () {
     // int integerProp

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/number_only_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for NumberOnly
 void main() {
-  final instance = NumberOnly();
+  final instance = NumberOnlyBuilder();
+  // TODO add properties to the builder and call build()
 
   group(NumberOnly, () {
     // num justNumber

samples/openapi3/client/petstore/dart-dio/petstore_client_lib_fake/test/order_test.dart

@@ -3,7 +3,8 @@ import 'package:test/test.dart';
 
 // tests for Order
 void main() {
-  final instance = Order();
+  final instance = OrderBuilder();
+  // TODO add properties to the builder and call build()
 
   group(Order, () {
     // int id