Comments on: IRepository: one size does not fit all

By: Nan Vantrease

Nan Vantrease — Sun, 20 Sep 2009 21:45:18 +0000

wei? nicht, wie Ihr Blog kam, muss ein Tippfehler gewesen sein,

By: Christian Horsdal

Christian Horsdal — Thu, 25 Jun 2009 09:58:41 +0000

Oops I got the link wrong. It’s: http://horsdal.blogspot.com/2009/06/exploring-wpf-business-application_24.html

By: Christian Horsdal

Christian Horsdal — Thu, 25 Jun 2009 09:57:06 +0000

Very good post. I definitely like way you split the repository interface into little self-contained traits.
Combining your approach with a few extension methods creates traits that carry implementation with them. That implementation is easily reused between concrete repositories. I show this approach in a blog post at http://horsdal.blogspot.com/2009/06/exploring-wpf-business-application_24.html/ …and hey, I think it turns out pretty nicely :-)

By: Richard

Richard — Sat, 11 Apr 2009 23:06:32 +0000

@Vasilio: my concrete repository is connected directly to NHibernate because the ORM easily allows this, and there is no additional logic in the repository (nor should there be, it’s just a collection).

In more complex mapping scenarios you might use a DAO-backed repository – see this article for the difference http://warren.mayocchi.com/2006/07/27/repository-or-dao/.

By: Vasilio Ruzanni

Vasilio Ruzanni — Sat, 11 Apr 2009 16:41:50 +0000

2Richard

And also I’d better tend to instead (of inheritance) delegate data-access functions to NHibernateRepository by using it inside ProjectRepository.

That’s just because I can’t clearly see any reason to inherit from it. Is there one?

By: Vasilio Ruzanni

Vasilio Ruzanni — Sat, 11 Apr 2009 16:31:11 +0000

It seems like we can almost clearly separate the concepts of “Domain Repositories” (and Domain Repositories Traits) and “Data Access Repositories”.

Should we?

By: Matt Freeman

Matt Freeman — Tue, 20 Jan 2009 21:48:00 +0000

I’m definitely leaning towards a generic DAO style inner repository, and concrete implementation of a domain repository containing this.

Part of the domain would be IPersonRepository exposing clear methods like GetPersonByFirstName(string firstName) etc… This would be implemented by a concrete repository that lives outside your domain that contains a nested concrete generic DAO style repository exposing Load FindAll etc…

By: Andrew Jackman

Andrew Jackman — Mon, 19 Jan 2009 09:49:31 +0000

This is called the “favour composition over inheritance” approach. See http://www.artima.com/lejava/articles/designprinciples4.html and http://www.objectmentor.com/resources/articles/inheritanceVsDelegation.pdf.