Add factory interface to support self initialized nullable value objects

src/Converter/ResourceConverter.php

@@ -8,6 +8,7 @@
 use Dogado\JsonApi\Model\Resource\ResourceInterface;
 use Dogado\JsonApi\Support\Model\CustomAttributeSetterInterface;
 use Dogado\JsonApi\Support\Model\DataModelAnalyser;
+use Dogado\JsonApi\Support\Model\ValueObjectFactoryInterface;
 use ReflectionClass;
 use ReflectionException;
 use ReflectionNamedType;
@@ -78,34 +79,48 @@ protected function setValue(ReflectionClass $reflection, object $model, array $p
         }
 
         $property = $reflection->getProperty($propertyName);
-        if (null !== $property->getType() && !$property->getType() instanceof ReflectionNamedType) {
+        $propertyType = $property->getType();
+        if (null !== $propertyType && !$propertyType instanceof ReflectionNamedType) {
             // other reflection types, like union types, are not supported
             return;
         }
 
         if (
-            null === $property->getType() ||
-            'mixed' === $property->getType()->getName() ||
-            $property->getType()->getName() === gettype($value)
+            null === $propertyType ||
+            'mixed' === $propertyType->getName() ||
+            $propertyType->getName() === gettype($value)
         ) {
             $property->setAccessible(true);
             $property->setValue($model, $value);
             return;
         }
 
-        if (class_exists($property->getType()->getName()) && 0 < count($propertyMap)) {
+        $propertyClassName = $propertyType->getName();
+        if (class_exists($propertyClassName) && 0 < count($propertyMap)) {
+            if (null === $value) {
+                return;
+            }
+
             $property->setAccessible(true);
             $valueObject = $property->getValue($model);
             if (null === $valueObject) {
-                return;
+                if (
+                    !(new ReflectionClass($propertyClassName))
+                        ->implementsInterface(ValueObjectFactoryInterface::class)
+                ) {
+                    return;
+                }
+                /** @var ValueObjectFactoryInterface $propertyClassName */
+                $valueObject = $propertyClassName::create();
+                $property->setValue($model, $valueObject);
             }
 
             $this->setValue(new ReflectionClass($valueObject), $valueObject, $propertyMap, $value);
             return;
         }
 
         if (null === $value) {
-            if (!$property->getType()->allowsNull()) {
+            if (!$propertyType->allowsNull()) {
                 throw DataModelSerializerException::propertyIsNotNullable(
                     $this->resource ? $this->resource->type() : 'unknown',
                     get_class($model),
@@ -122,7 +137,7 @@ protected function setValue(ReflectionClass $reflection, object $model, array $p
             return;
         }
 
-        switch ($property->getType()->getName()) {
+        switch ($propertyType->getName()) {
             case 'boolean':
             case 'bool':
                 $property->setAccessible(true);

src/Support/Model/ValueObjectFactoryInterface.php

@@ -0,0 +1,10 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Dogado\JsonApi\Support\Model;
+
+interface ValueObjectFactoryInterface
+{
+    public static function create(): self;
+}

tests/Converter/ResourceConverterTest.php

@@ -41,6 +41,10 @@ public function testResourceToModel(): void
                     'number' => (string) $this->faker()->numberBetween(),
                     'ignoreOnNull' => $this->faker()->text(),
                 ],
+                'nullableValueObject' => [
+                    'number' => (string) $this->faker()->numberBetween(),
+                    'ignoreOnNull' => $this->faker()->text(),
+                ],
                 'arrayItems' => [
                     $this->faker->slug() => $this->faker->text(),
                     $this->faker->slug() => $this->faker->text(),
@@ -82,6 +86,15 @@ public function testResourceToModel(): void
             $attributes->getSubCollection('values')->getRequired('ignoreOnNull'),
             $model->getValueObject()->getIgnoreOnNull()
         );
+        $this->assertNotNull($model->getNullableValueObject());
+        $this->assertEquals(
+            (int) $attributes->getSubCollection('nullableValueObject')->getRequired('number'),
+            $model->getNullableValueObject()->getSubItem()
+        );
+        $this->assertEquals(
+            $attributes->getSubCollection('nullableValueObject')->getRequired('ignoreOnNull'),
+            $model->getNullableValueObject()->getIgnoreOnNull()
+        );
         $this->assertEquals(
             $attributes->get('arrayItems'),
             $model->getArrayItems()