Dependency Injection

Package: Skymly.DesignPatterns.Extensions.DependencyInjection

Overview

Optional Microsoft.Extensions.DependencyInjection integration. Does not replace container lifetime rules — it registers generated registries and resolves implementations from IServiceProvider.

Manual registration

Extension methods such as:

• AddStrategyRegistry<TKey, TStrategy>(...)
• AddFactoryRegistry<TKey, TProduct>(...)
• AddAsyncFactoryRegistry<TKey, TProduct>(...)
• AddPooledFactoryRegistry<TKey, TProduct>(..., poolSize)
• AddHandlerPipeline<TContext>(...)
• AddTransitionTable<TState, TTrigger>(...)
• AddStateMachine<TState, TTrigger>(...)

Async factory registry

services.AddAsyncFactoryRegistry<string, IProduct>(builder =>
{
    builder.Register("standard", ct => new ValueTask<IProduct>(new StandardProduct()));
});

Pooled factory registry

services.AddPooledFactoryRegistry<string, IProduct>(builder =>
{
    builder.Register("buffer", () => new BufferProduct());
}, poolSize: 16);

State machine

services.AddTransitionTable<OrderStatus, OrderTrigger>();
services.AddStateMachine<OrderStatus, OrderTrigger>();

Use ServiceLifetime.Transient for AddStateMachine when each consumer needs its own state tracking.

Generated RegisterDi

When the DI package (or its MSBuild targets) is referenced, Strategy / Factory / Handler / State / Composite / Decorator / EventAggregator generators emit:

PaymentStrategyRegistry.RegisterDi(services);
OrderStatusStateMachine.RegisterDi(services);
MenuNodeCompositeCatalog.RegisterDi(services);
PaymentServiceDecoratorStack.RegisterDi(services);
OrderPlacedEventHandlerRegistry.RegisterDi(services);

Registries register as singletons by default. Factory registries default to Transient for implementation types (matching factory semantics — each Create returns a new instance).

Project setup

Reference DesignPatterns.Extensions.DependencyInjection and import its targets (see package / sibling project build/DesignPatterns.Extensions.DependencyInjection.targets).

Set DesignPatternsSampleKind=DependencyInjection in sample projects for the shared MSBuild imports in DesignPatterns.Samples.

Sample

DesignPatterns.Samples.DependencyInjection

Note on meta package

The core Skymly.DesignPatterns NuGet meta package does not include DI or Autofac extensions. Install them separately from nuget.org:

• Skymly.DesignPatterns.Extensions.DependencyInjection
• Skymly.DesignPatterns.Extensions.Autofac

Autofac integration

The Skymly.DesignPatterns.Extensions.Autofac package provides Autofac integration symmetric to the MSDI RegisterDi pattern. When referenced, the source generator emits RegisterAutofac(ContainerBuilder) and Create(ILifetimeScope) methods for Strategy, Factory, Handler, and State registries.

var builder = new ContainerBuilder();
PaymentStrategyRegistry.RegisterAutofac(builder);

using var container = builder.Build();
var registry = container.Resolve<IStrategyRegistry<string, IPaymentStrategy>>();

RegisterAutofac accepts optional parameters:

• sharing — InstanceSharing.Shared (default, SingleInstance()) or InstanceSharing.None (InstancePerDependency())
• serviceKey — optional key for keyed registration

The Autofac extension can be referenced alongside Skymly.DesignPatterns.Extensions.DependencyInjection — both RegisterDi and RegisterAutofac methods are generated. The Autofac extension is not included in the meta package; reference it separately.