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