Unit-of-Work-Muster

Übersicht

Das Unit-of-Work-Muster verwaltet eine Liste von Objekten, die von einer Geschäftstransaktion betroffen sind, und koordiniert das Schreiben von Änderungen. Es stellt sicher, dass alle zugehörigen Änderungen zusammen committed oder bei einem Fehler zurückgerollt werden.

Zweck

1. Transaktionsverwaltung - Gruppieren Sie zugehörige Operationen
2. Änderungsverfolgung - Verfolgen Sie geänderte Entitäten
3. Batch-Operationen - Optimieren Sie Datenbankschreibvorgänge
4. Konsistenz - Stellen Sie Datenintegrität sicher

Implementierung

Unit-of-Work-Schnittstelle

<?php

declare(strict_types=1);

namespace XoopsModules\MyModule\Infrastructure;

interface UnitOfWorkInterface
{
    public function begin(): void;
    public function commit(): void;
    public function rollback(): void;
    public function registerNew(object $entity): void;
    public function registerDirty(object $entity): void;
    public function registerDeleted(object $entity): void;
}

Grundlegende Implementierung

<?php

declare(strict_types=1);

namespace XoopsModules\MyModule\Infrastructure;

final class UnitOfWork implements UnitOfWorkInterface
{
    private array $newEntities = [];
    private array $dirtyEntities = [];
    private array $deletedEntities = [];
    private bool $inTransaction = false;

    public function __construct(
        private readonly \XoopsDatabase $db,
        private readonly EntityMapperRegistry $mappers
    ) {}

    public function begin(): void
    {
        if ($this->inTransaction) {
            throw new \RuntimeException('Transaction already started');
        }

        $this->db->query('START TRANSACTION');
        $this->inTransaction = true;
    }

    public function commit(): void
    {
        if (!$this->inTransaction) {
            throw new \RuntimeException('No transaction in progress');
        }

        try {
            $this->insertNew();
            $this->updateDirty();
            $this->deleteRemoved();

            $this->db->query('COMMIT');
            $this->clear();
        } catch (\Exception $e) {
            $this->rollback();
            throw $e;
        }
    }

    public function rollback(): void
    {
        if ($this->inTransaction) {
            $this->db->query('ROLLBACK');
            $this->clear();
        }
    }

    public function registerNew(object $entity): void
    {
        $id = spl_object_id($entity);
        $this->newEntities[$id] = $entity;
    }

    public function registerDirty(object $entity): void
    {
        $id = spl_object_id($entity);
        if (!isset($this->newEntities[$id])) {
            $this->dirtyEntities[$id] = $entity;
        }
    }

    public function registerDeleted(object $entity): void
    {
        $id = spl_object_id($entity);
        unset($this->newEntities[$id], $this->dirtyEntities[$id]);
        $this->deletedEntities[$id] = $entity;
    }

    private function insertNew(): void
    {
        foreach ($this->newEntities as $entity) {
            $mapper = $this->mappers->getMapper($entity::class);
            $mapper->insert($entity);
        }
    }

    private function updateDirty(): void
    {
        foreach ($this->dirtyEntities as $entity) {
            $mapper = $this->mappers->getMapper($entity::class);
            $mapper->update($entity);
        }
    }

    private function deleteRemoved(): void
    {
        foreach ($this->deletedEntities as $entity) {
            $mapper = $this->mappers->getMapper($entity::class);
            $mapper->delete($entity);
        }
    }

    private function clear(): void
    {
        $this->newEntities = [];
        $this->dirtyEntities = [];
        $this->deletedEntities = [];
        $this->inTransaction = false;
    }
}

Usage in Services

final class ArticleService
{
    public function __construct(
        private readonly UnitOfWorkInterface $unitOfWork,
        private readonly ArticleRepository $articles,
        private readonly CommentRepository $comments
    ) {}

    public function publishWithComments(
        Article $article,
        array $comments
    ): void {
        $this->unitOfWork->begin();

        try {
            // Mark article as modified
            $article->publish();
            $this->unitOfWork->registerDirty($article);

            // Add new comments
            foreach ($comments as $comment) {
                $this->unitOfWork->registerNew($comment);
            }

            // Commit all changes together
            $this->unitOfWork->commit();

        } catch (\Exception $e) {
            $this->unitOfWork->rollback();
            throw $e;
        }
    }
}

With Repository Integration

final class ArticleRepository implements ArticleRepositoryInterface
{
    public function __construct(
        private readonly UnitOfWorkInterface $unitOfWork,
        private readonly ArticleMapper $mapper
    ) {}

    public function add(Article $article): void
    {
        $this->unitOfWork->registerNew($article);
    }

    public function update(Article $article): void
    {
        $this->unitOfWork->registerDirty($article);
    }

    public function remove(Article $article): void
    {
        $this->unitOfWork->registerDeleted($article);
    }

    public function findById(ArticleId $id): ?Article
    {
        return $this->mapper->findById($id);
    }
}

Best Practices

1. Short Transactions - Keep transactions brief
2. Single Responsibility - One unit of work per business operation
3. Clear Boundaries - Define transaction scope clearly
4. Error Handling - Always handle rollback scenarios
5. Avoid Nested - Don’t nest units of work

Related Documentation

• Repository-Layer - Repository pattern
• Service-Layer - Service pattern
• ../Database/Database-Schema - Database operations
• Domain-Model - Domain entities