Event sourced form mapping

DataMapper.php

<?php

use Symfony\Component\Form\Exception\UnexpectedTypeException;
use Symfony\Component\Form\Extension\Core\DataMapper\PropertyPathMapper;

/**
 * Custom datamapper 
 * This uses normal getters to fill the form using PropertyPathMapper.
 * But for setters it go's the custom route.
 */
class MyDataMapper extends PropertyPathMapper {
    /**
     * {@inheritdoc}
     */
    public function mapFormsToData($forms, &$data)
    {
        if (null === $data) {
            return;
        }

        if (!$data instanceof MySource) {
            throw new UnexpectedTypeException($data, sprintf('Expected instance of %s', MySource::class));
        }

        // Get the submitted data
        // In some cases you may want to also normalize or do some very funky validation here
        // If that fails you can throw a `Symfony\Component\Form\Exception\TransformationFailedException`.
        $submittedData = $this->retrieveData($forms);

        // Call the actual method that will apply the changes
        $data->myChangeMethod(
            $submittedData['<element_name_1>'],
            $submittedData['<element_name_2>']
        );
    }
    
    /**
     * Get the data form the given forms/elements and puts it into a array.
     * 
     * @param \Symfony\Component\Form\Form[] $forms
     * @return array
     */
    private function retrieveData($forms)
    {
        $data = [];

        /** @var \Symfony\Component\Form\Form[] $forms */
        foreach ($forms as $form) {
            $propertyPath = $form->getPropertyPath();
            $config = $form->getConfig();

            // Write-back is disabled if the form is not synchronized (transformation failed),
            // if the form was not submitted and if the form is disabled (modification not allowed)
            if (null === $propertyPath || !$config->getMapped() || !$form->isSubmitted() || !$form->isSynchronized() || $form->isDisabled()) {
                continue;
            }

            $data[(string)$propertyPath] = $form->getData();
        }

        return $data;
    }
}

Form.php

<?php

use Symfony\Component\Form\AbstractType;
use Symfony\Component\Form\FormBuilderInterface;

class MySexyFormType extends AbstractType
{
    public function buildForm(FormBuilderInterface $builder, array $options)
    {
        // ...
        $builder->setDataMapper(new MyDataMapper());
    }
}