Pola Model Domain

Ikhtisar

Pola Model Domain mewakili konsep bisnis, aturan, dan logika aplikasi Anda. Dalam pengembangan module XOOPS, model domain merangkum entitas bisnis core dan perilakunya.

Entitas vs Objek Nilai

Entitas

Entitas memiliki identitas dan siklus hidup:

<?php

declare(strict_types=1);

namespace XoopsModules\MyModule\Entity;

use XoopsModules\MyModule\ValueObject\ArticleId;

final class Article
{
    private bool $isNew = true;

    public function __construct(
        private ArticleId $id,
        private string $title,
        private string $content,
        private int $authorId,
        private int $categoryId,
        private ArticleStatus $status,
        private \DateTimeImmutable $createdAt,
        private ?\DateTimeImmutable $updatedAt = null
    ) {}

    public static function create(
        string $title,
        string $content,
        int $authorId,
        int $categoryId
    ): self {
        return new self(
            id: ArticleId::generate(),
            title: $title,
            content: $content,
            authorId: $authorId,
            categoryId: $categoryId,
            status: ArticleStatus::DRAFT,
            createdAt: new \DateTimeImmutable()
        );
    }

    public function publish(): void
    {
        if ($this->status === ArticleStatus::PUBLISHED) {
            throw new \DomainException('Article is already published');
        }

        $this->status = ArticleStatus::PUBLISHED;
        $this->updatedAt = new \DateTimeImmutable();
    }

    public function updateContent(string $title, string $content): void
    {
        $this->title = $title;
        $this->content = $content;
        $this->updatedAt = new \DateTimeImmutable();
    }

    // Getters...
    public function getId(): ArticleId { return $this->id; }
    public function getTitle(): string { return $this->title; }
    public function getContent(): string { return $this->content; }
    public function getStatus(): ArticleStatus { return $this->status; }
    public function isNew(): bool { return $this->isNew; }

    public function markAsPersisted(): void
    {
        $this->isNew = false;
    }
}

Nilai Objek

Objek Nilai tidak dapat diubah dan dibandingkan berdasarkan nilai:

<?php

declare(strict_types=1);

namespace XoopsModules\MyModule\ValueObject;

final class ArticleId
{
    private function __construct(
        private readonly string $value
    ) {}

    public static function generate(): self
    {
        return new self(\Xmf\Ulid::generate());
    }

    public static function fromString(string $value): self
    {
        if (empty($value)) {
            throw new \InvalidArgumentException('ArticleId cannot be empty');
        }
        return new self($value);
    }

    public function toString(): string
    {
        return $this->value;
    }

    public function equals(self $other): bool
    {
        return $this->value === $other->value;
    }
}

Agregat

Agregat adalah kelompok objek domain yang diperlakukan sebagai satu unit:

final class Category
{
    private array $articles = [];

    public function __construct(
        private CategoryId $id,
        private string $name,
        private ?CategoryId $parentId = null
    ) {}

    public function addArticle(Article $article): void
    {
        if ($article->getCategoryId() !== $this->id->toInt()) {
            throw new \DomainException('Article does not belong to this category');
        }
        $this->articles[] = $article;
    }

    public function getArticleCount(): int
    {
        return count($this->articles);
    }
}

Peristiwa Domain

Tangkap kejadian domain penting:

final class ArticlePublishedEvent
{
    public function __construct(
        public readonly ArticleId $articleId,
        public readonly int $authorId,
        public readonly \DateTimeImmutable $publishedAt
    ) {}
}

Enum untuk Status

Gunakan enum PHP 8.2+ untuk nilai status aman tipe:

enum ArticleStatus: string
{
    case DRAFT = 'draft';
    case PENDING_REVIEW = 'pending';
    case PUBLISHED = 'published';
    case ARCHIVED = 'archived';

    public function canTransitionTo(self $newStatus): bool
    {
        return match($this) {
            self::DRAFT => in_array($newStatus, [self::PENDING_REVIEW, self::ARCHIVED]),
            self::PENDING_REVIEW => in_array($newStatus, [self::DRAFT, self::PUBLISHED]),
            self::PUBLISHED => $newStatus === self::ARCHIVED,
            self::ARCHIVED => false,
        };
    }
}

Invarian

Lindungi aturan domain dalam entitas:

final class Article
{
    public function setTitle(string $title): void
    {
        if (strlen($title) < 5) {
            throw new \DomainException('Title must be at least 5 characters');
        }
        if (strlen($title) > 255) {
            throw new \DomainException('Title cannot exceed 255 characters');
        }
        $this->title = $title;
    }

    public function archive(): void
    {
        if ($this->status === ArticleStatus::DRAFT) {
            throw new \DomainException('Cannot archive a draft article');
        }
        $this->status = ArticleStatus::ARCHIVED;
    }
}

Praktik Terbaik

1. Model Domain Kaya - Masukkan perilaku dalam entitas, bukan layanan
2. Objek Nilai Abadi - Objek nilai tidak boleh berubah
3. Metode Pabrik - Gunakan metode pabrik statis untuk konstruksi kompleks
4. Klausul Penjaga - Validasi input pada batas entitas
5. Peristiwa Domain - Menangkap perubahan status yang signifikan
6. Bahasa yang Ada di Mana-Mana - Gunakan terminologi bisnis dalam kode

Dokumentasi Terkait

• Lapisan Layanan - Layanan aplikasi
• Lapisan Repositori - Kegigihan
• Pola DTO - Transfer data
• Sistem Acara - Acara domain