Abstract Factory Generator

[GenerateAbstractFactory] emits an AbstractFactory<TKey> from declarative product-family attributes. Use it when the family matrix is known at compile time and should stay reviewable, type-safe, and importable through normal application composition.

Quick Start

using PatternKit.Generators.Factories;

[GenerateAbstractFactory(typeof(Platform), FactoryMethodName = "Create", ServiceProviderFactoryMethodName = "CreateFromServices")]
[AbstractFactoryProduct(Platform.Windows, typeof(IButton), typeof(WindowsButton))]
[AbstractFactoryProduct(Platform.Windows, typeof(ITextBox), typeof(WindowsTextBox))]
[AbstractFactoryProduct(Platform.Linux, typeof(IButton), typeof(LinuxButton))]
[AbstractFactoryProduct(Platform.Linux, typeof(ITextBox), typeof(LinuxTextBox))]
public static partial class PlatformWidgetFactory;

Generated API:

public static AbstractFactory<Platform> Create();
public static AbstractFactory<Platform> CreateFromServices(IServiceProvider services);

The normal factory path uses public parameterless constructors. The optional service-provider path uses ActivatorUtilities.CreateInstance<T>(services), so products can add constructor dependencies when the importing app registers them with IServiceCollection.

Behavior

• [GenerateAbstractFactory] must be placed on a partial class or struct.
• [AbstractFactoryProduct] declares one contract/implementation pair for one family key.
• ImplementationType must be a concrete class assignable to ContractType.
• Each generated factory calls the runtime fluent API: AbstractFactory<TKey>.Create().Family(...).Product<...>().Build().
• Set IsDefaultFamily = true on a product to add it to the default family instead of a keyed family.

Diagnostics

ID	Meaning
PKAF001	The generated host type is not partial.
PKAF002	No products were declared.
PKAF003	A product declaration has an invalid key, contract, implementation, or constructor.
PKAF004	A family declares the same product contract more than once.

Example Source

• src/PatternKit.Examples/AbstractFactoryDemo/AbstractFactoryDemo.cs
• test/PatternKit.Examples.Tests/AbstractFactoryDemo/AbstractFactoryDemoTests.cs
• test/PatternKit.Generators.Tests/AbstractFactoryGeneratorTests.cs