roots.md

Roots

Sometimes you need roots for all types inherited from available at compile time at the point where the method is called.

using Shouldly;
using Pure.DI;

DI.Setup(nameof(Composition))
    .Bind().As(Lifetime.Singleton).To<Dependency>()
    .Roots<IService>("My{type}");

var composition = new Composition();
composition.MyService1.ShouldBeOfType<Service1>();
composition.MyService2.ShouldBeOfType<Service2>();

interface IDependency;

class Dependency : IDependency;

interface IService;

class Service1(IDependency dependency) : IService;

class Service2(IDependency dependency) : IService;

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 Dependency? _singletonDependency43;

  [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 Service2 MyService2
  {
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    get
    {
      if (_root._singletonDependency43 is null)
      {
        using (_lock.EnterScope())
        {
          if (_root._singletonDependency43 is null)
          {
            _root._singletonDependency43 = new Dependency();
          }
        }
      }

      return new Service2(_root._singletonDependency43);
    }
  }

  public Service1 MyService1
  {
    [MethodImpl(MethodImplOptions.AggressiveInlining)]
    get
    {
      if (_root._singletonDependency43 is null)
      {
        using (_lock.EnterScope())
        {
          if (_root._singletonDependency43 is null)
          {
            _root._singletonDependency43 = new Dependency();
          }
        }
      }

      return new Service1(_root._singletonDependency43);
    }
  }
}

Class diagram:

---
 config:
  class:
   hideEmptyMembersBox: true
---
classDiagram
	Dependency --|> IDependency
	Composition ..> Service2 : Service2 MyService2
	Composition ..> Service1 : Service1 MyService1
	Service2 o-- "Singleton" Dependency : IDependency
	Service1 o-- "Singleton" Dependency : IDependency
	namespace Pure.DI.UsageTests.Basics.RootsScenario {
		class Composition {
		<<partial>>
		+Service1 MyService1
		+Service2 MyService2
		}
		class Dependency {
			+Dependency()
		}
		class IDependency {
			<<interface>>
		}
		class Service1 {
		}
		class Service2 {
		}
	}

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