HasDomainModel.php

<?php

declare (strict_types = 1);

namespace App\Infrastructure;

use App\Domain;

trait HasDomainModel
{
    public function mapToDomainModel()
    {
        $model = (new \ReflectionClass($this->getDomainModelClass()))->newInstanceWithoutConstructor();

        $hydrator = (function($entity) {
            return function(string $propertyName) use ($entity) {
                return function(callable $propertyValue) use ($entity, $propertyName) {
                    return function(Domain\Program $program) use ($entity, $propertyName, $propertyValue) {
                        $program->{$propertyName} = $propertyValue($entity);
                    };
                };
            };
        })($this);

        $mapper = $this->getPropertyMapper();
        foreach ($this->getDomainMapping() as $entityPropertyName => $domainModelPropertyName) {
            $hydrate = $hydrator($domainModelPropertyName)(
                isset($mapper[$entityPropertyName]) ? $mapper[$entityPropertyName] : function($entity) use ($entityPropertyName) {
                    return $entity->{'get'.ucfirst($entityPropertyName)}();
                }
            );
            $hydrate = \Closure::bind($hydrate, null, $model);
            $hydrate($model);
        }

        return $model;
    }
}

Program.php

<?php

declare (strict_types = 1);

namespace App\Infrastructure\Entity;

use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\ORM\Mapping as ORM;
use App\Infrastructure\HasDomainModel;
use App\Domain;


/**
 * @ORM\Entity
 */
final class Program
{
    use HasDomainModel;

    /**
     * @ORM\Id
     * @ORM\Column(type="string", length=36)
     */
    private $id;

    /**
     * @ORM\Column(type="string")
     */
    private $description;

    /**
     * @ORM\Column(type="integer")
     */
    private $maxParticipants;

    /**
     * @ORM\ManyToMany(targetEntity="Participant", cascade={"persist"})
     */
    private $participants;

    public function __construct()
    {
        $this->participants = new ArrayCollection();
    }

    public function getId()
    {
        return $this->id;
    }

    public function getDescription()
    {
        return $this->description;
    }

    public function setDescription($description)
    {
        $this->description = $description;
    }

    public function getMaxParticipants()
    {
        return $this->maxParticipants;
    }

    public function setMaxParticipants($maxParticipants)
    {
        $this->maxParticipants = $maxParticipants;
    }

    public function getParticipants()
    {
        return $this->participants;
    }

    public function setParticipants($participants)
    {
        $this->participants = $participants;
    }

    private function getDomainModelClass(): string
    {
        return Domain\Program::class;
    }

    private function getDomainMapping(): array
    {
        return [
            'id' => 'programId',
            'description' => 'description',
            'maxParticipants' => 'maxParticipants',
        ];
    }

    private function getPropertyMapper(): array
    {
        return [
            'id' => function(Program $entity) {
                return Domain\ProgramId::fromString($entity->getId());
            },
        ];
    }
}