accumulators.md

Accumulators

Accumulators allow you to accumulate instances of certain types and lifetimes.

using Shouldly;
using Pure.DI;
using static Pure.DI.Lifetime;

DI.Setup(nameof(Composition))
    .Accumulate<IAccumulating, MyAccumulator>(Transient, Singleton)
    .Bind<IDependency>().As(PerBlock).To<AbcDependency>()
    .Bind<IDependency>(Tag.Type).To<AbcDependency>()
    .Bind<IDependency>(Tag.Type).As(Singleton).To<XyzDependency>()
    .Bind<IService>().To<Service>()
    .Root<(IService service, MyAccumulator accumulator)>("Root");

var composition = new Composition();
var (service, accumulator) = composition.Root;
accumulator.Count.ShouldBe(3);
accumulator[0].ShouldBeOfType<AbcDependency>();
accumulator[1].ShouldBeOfType<XyzDependency>();
accumulator[2].ShouldBeOfType<Service>();

interface IAccumulating;

class MyAccumulator : List<IAccumulating>;

interface IDependency;

class AbcDependency : IDependency, IAccumulating;

class XyzDependency : IDependency, IAccumulating;

interface IService;

class Service(
    [Tag(typeof(AbcDependency))] IDependency dependency1,
    [Tag(typeof(XyzDependency))] IDependency dependency2,
    IDependency dependency3)
    : IService, IAccumulating;

Running this code sample locally

• Make sure you have the .NET SDK 9.0 or later is installed

dotnet --list-sdk

• Create a net9.0 (or later) console application

dotnet new console -n Sample

• Add references to NuGet packages
  • Pure.DI
  • Shouldly

dotnet add package Pure.DI
dotnet add package Shouldly

• Copy the example code into the Program.cs file

You are ready to run the example 🚀

dotnet run

The following partial class will be generated:

partial class Composition
{
  private readonly Composition _root;
  private readonly Lock _lock;

  private XyzDependency? _singletonXyzDependency53;

  [OrdinalAttribute(256)]
  public Composition()
  {
    _root = this;
    _lock = new Lock();
  }

  internal Composition(Composition parentScope)
  {
    _root = (parentScope ?? throw new ArgumentNullException(nameof(parentScope)))._root;
    _lock = _root._lock;
  }

  public (IService service, MyAccumulator accumulator) Root
  {
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    get
    {
      var accumulator56 = new MyAccumulator();
      AbcDependency transientAbcDependency3 = new AbcDependency();
      using (_lock.EnterScope())
      {
        accumulator56.Add(transientAbcDependency3);
      }

      if (_root._singletonXyzDependency53 is null)
      {
        using (_lock.EnterScope())
        {
          if (_root._singletonXyzDependency53 is null)
          {
            XyzDependency _singletonXyzDependency53Temp;
            _singletonXyzDependency53Temp = new XyzDependency();
            accumulator56.Add(_singletonXyzDependency53Temp);
            Thread.MemoryBarrier();
            _root._singletonXyzDependency53 = _singletonXyzDependency53Temp;
          }
        }
      }

      AbcDependency perBlockAbcDependency4 = new AbcDependency();
      Service transientService1 = new Service(transientAbcDependency3, _root._singletonXyzDependency53, perBlockAbcDependency4);
      using (_lock.EnterScope())
      {
        accumulator56.Add(transientService1);
      }

      return (transientService1, accumulator56);
    }
  }
}

Class diagram:

---
 config:
  class:
   hideEmptyMembersBox: true
---
classDiagram
	AbcDependency --|> IDependency : typeof(Pure.DI.UsageTests.Advanced.AccumulatorScenario.AbcDependency) 
	XyzDependency --|> IDependency : typeof(Pure.DI.UsageTests.Advanced.AccumulatorScenario.XyzDependency) 
	Service --|> IService
	Composition ..> ValueTupleᐸIServiceˏMyAccumulatorᐳ : ValueTupleᐸIServiceˏMyAccumulatorᐳ Root
	Service o-- "PerBlock" AbcDependency : IDependency
	Service *--  AbcDependency : typeof(Pure.DI.UsageTests.Advanced.AccumulatorScenario.AbcDependency)  IDependency
	Service o-- "Singleton" XyzDependency : typeof(Pure.DI.UsageTests.Advanced.AccumulatorScenario.XyzDependency)  IDependency
	ValueTupleᐸIServiceˏMyAccumulatorᐳ *--  Service : IService
	ValueTupleᐸIServiceˏMyAccumulatorᐳ *--  MyAccumulator : MyAccumulator
	namespace Pure.DI.UsageTests.Advanced.AccumulatorScenario {
		class AbcDependency {
			+AbcDependency()
		}
		class Composition {
		<<partial>>
		+ValueTupleᐸIServiceˏMyAccumulatorᐳ Root
		}
		class IDependency {
			<<interface>>
		}
		class IService {
			<<interface>>
		}
		class MyAccumulator {
		}
		class Service {
			+Service(IDependency dependency1, IDependency dependency2, IDependency dependency3)
		}
		class XyzDependency {
			+XyzDependency()
		}
	}
	namespace System {
		class ValueTupleᐸIServiceˏMyAccumulatorᐳ {
				<<struct>>
			+ValueTuple(IService item1, MyAccumulator item2)
		}
	}

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