CODEWITHSUNDEEP
delphidependency-injection
mjn
mjn

Reputation: 36654

Is there a Dependency Injection Framework for Delphi with attribute-based injection?

I would love to be able to code in Delphi this way, simply annotating a field:

type
  TMyClass = class
  private
    [Inject]
    Factory: ISomeFactory;
    ...
  end;

or by attributing a setter

type
  TMyClass = class
  private
    FFactory: ISomeFactory;

    [Inject]
    procedure SetFactory(const AFactory: ISomeFactory);
    ...
  public
    property Factory: ISomeFactory read FFactory write SetFactory;
  end;

The background: I am moving old code to a service-oriented architecture and find that referencing the service layer always leads to constructs like

DataModule1.ServiceLayerInstance1.SubSystemN.InvokeSomething(Params, ...);

which could be much shorter like

type
  Form1 = class(TForm1)
  private
    [Inject]
    SubsystemN: ISubsystemN;
    ...
  end;
  ...
  SubsystemN.InvokeSomething(Params, ...);

Upvotes: 7

Views: 1710

Answers (2)

jfoliveira
jfoliveira

Reputation: 2168

You can achieve this goal with the Emballo OpenSource project.

See the project on Google Code: http://code.google.com/p/emballo/wiki/WhyDependencyInjection

Upvotes: 2

Nick Hodges
Nick Hodges

Reputation: 17118

Yes, there is. The Delphi Spring Framework

http://www.spring4d.com/

does precisely this. It has an [Inject] attribute.

One caveat -- to use it, you need to include the Spring unit in your code where the attribute is defined. Otherwise, the compiler will ignore the attribute.

Upvotes: 10

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