Factory Generator

Generate DDD-compliant Factories for complex domain object creation.

Factory Characteristics

• Encapsulates Creation: Hides complex instantiation logic
• Validates Input: Ensures valid object creation
• Named Constructors: Provides semantic creation methods
• Domain Layer: Lives in Domain, no infrastructure dependencies
• Returns Valid Objects: Never creates invalid domain objects
• Static or Instance: Static for simple, instance for dependencies

When to Use Factory

| Scenario | Example | |----------|---------| | Complex construction logic | OrderFactory::createFromCart() | | Multiple creation paths | User::register(), User::createAdmin() | | Aggregate creation | PolicyFactory::createWithCoverage() | | Reconstruction from persistence | OrderFactory::reconstitute() | | Creation with validation | InvoiceFactory::create() |

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Generation Process

Step 1: Determine Factory Type

• Static Factory: No dependencies, simple validation
• Instance Factory: Needs domain services or repositories

Step 2: Generate Factory

Path: src/Domain/{BoundedContext}/Factory/

1. {Entity}Factory.php — Main factory class

Step 3: Define Creation Methods

1. create() — Primary creation with validation
2. createFrom{Source}() — Creation from other objects
3. reconstitute() — Reconstruction from persistence (no validation)

Step 4: Generate Tests

Path: tests/Unit/Domain/{BoundedContext}/Factory/

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File Placement

| Component | Path | |-----------|------| | Factory | src/Domain/{BoundedContext}/Factory/ | | Unit Tests | tests/Unit/Domain/{BoundedContext}/Factory/ |

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Naming Conventions

| Pattern | Example | |---------|---------| | Factory Class | {EntityName}Factory | | Create Method | create(), createFrom{Source}() | | Named Constructor | create{Variant}() | | Reconstitute | reconstitute() | | Validation | validate{Aspect}() |

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Quick Template Reference

Static Factory

final class {Entity}Factory
{
    public static function create({parameters}): {Entity}
    {
        self::validate({parameters});
        return new {Entity}({constructorArgs});
    }

    public static function createFrom{Source}({SourceType} $source): {Entity}
    {
        return new {Entity}({mappedArgs});
    }

    public static function reconstitute({allFields}): {Entity}
    {
        return new {Entity}({allArgs});
    }

    private static function validate({parameters}): void
    {
        {validationLogic}
    }
}

Instance Factory

final readonly class {Entity}Factory
{
    public function __construct(
        private {DomainService} $service,
        private {Repository} $repository
    ) {}

    public function create({parameters}): {Entity}
    {
        {creationLogicWithDependencies}
    }
}

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Anti-patterns to Avoid

| Anti-pattern | Problem | Solution | |--------------|---------|----------| | Infrastructure in Factory | DB calls in factory | Keep pure domain logic | | No Validation | Creates invalid objects | Validate before creation | | Too Many Parameters | Hard to use | Use Value Objects, Builder | | Mutable Factory | Stateful creation | Make stateless or readonly | | Missing Reconstitute | Can't hydrate from DB | Add reconstitute method |

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References

For complete PHP templates and examples, see:

• references/templates.md — Static Factory, Instance Factory, Test templates
• references/examples.md — Order, User, Policy factory examples and tests