Hi Ralf, I am currently trying to learn Flow Design, IODA, IOSP etc. with your book Flow Design Programming with ease and with your colleague Stefan Lieser´s book Flow Design. I also read your articles in the DotnetPro magazine and investigating the github repos of you and Stefan. I find your ideas interesting, and I am excited if I can introduce these concepts in our brown field projects (more or less).

But I am little bit disappointed about the less reaction of the community here and your other posts. It would be great to see if others could implement these concepts in their business applicatons successfully and what challanges they had to solve.

It would be great to have others to talk about questions, ideas etc. Is there any community place where IODA/IOSP is discussed?

Regarding Sleepy Hollow Architecture and the Interactors, it seems that you and Stefan have a different definition of a flow design based software structure. In Stefan´s book (page 177) it seems that the Interactors class is that what here in your post is the Processor. So Stefans Interactors is integrating Domain and Provider. His Interactors is not integrating UI. In Stefans architecture he has a Controller class that integrates UI and Interactors.

Can you give some clarification of my confusion please?

Are you both still working together or do you have different opinions?

Why two books and not one book together?



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Glad to hear you're delving into Flow Design and IODA!

Why isn't the community more interested in IODA, IOSP etc.? Because people are drowned by the older principles/concepts like SOLID or Hex/Clean Architecture. Over time they have got so much more visibility, that's hard to match. Stefan and I were always focused on the DACH market.

Check out the Clean Code Developer community on Discord: https://discord.gg/9p9YX7T8 (link valid until 25.8.23). We are excited to hear about your insights and questions there.

Sleepy hollow is "on top of IODA". It came later.

The terminology in IODA has changed. In the beginning the integration strata were called Controller and Interactor. Later I changed Controller to Application and Interactor to Processor - and Stefan kept the former.

I don't mind that much. All terms have their merits:

- Application: I find this a more general term; Controller is more suggestive of a web service.

- Processor: I find this a more general term. Interactor is alluding to the Clean Architekture and is pointing at where "things really happen" in an interaction diagram used in Slicing.

Stefan and I parted ways some years ago. He's actively promoting Flow Design with his CCD academy trainings; I've retreated to Bulgaria and am not really actively/heavily involved in Clean Code Development anymore. Sometimes I write about it in this blog. But mostly I'm concerned with matters not related to CCD. I'm happy with concepts developed from 2008 until now.

Why two books? Because this topic (like any other) deserves different points of view.😁 We are sharing most opinions on this, but we're also differing in some aspects.

And any additional book on Flow Design of course is welcome, too😁 Why not continue the development of this "art"?

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Hi Ralf, thank you for this good article. One question, as all found links to the discord group are expired. Is that community still existing and open to join?

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Come and join the server: https://discord.gg/MNRYmGJK

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Thank you for your quick reply and the clarifications, and of course for the discord invitation, I appreciate this very much!! Writing a book was not in my mind (yet :D). First I need to learn and gather experience in practice of our brown field project. But the hardest part will be to point our architects and developer team to these concepts. It would be nice to hear/read success stories, it would help as an argument.

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Hey Ralf, how's it going?

The Free World Theory substack is taking off. Currently have almost 1,000 subscribers, and more and more people are recommending it. Thanks for the early support!

Hope everything is well with you.


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