[Podcast] Using WCF for Entity and Activity Services to Implement Business Services

Ask Udi Podcast – Udi Dahan – The Software Simplist

This week we return to the topic of Entity, Activity, and Process services and compares their usages as top-level SOA elements and as implementation details of the application architecture inside a business service.

And the question that this answers is:

Hi Udi,

We’ve been having some discussions about how to implement our latest project using SOA and this is what we came up with:

Every activity is a method, which is broken into a class ( Think separation of concerns ), so we get high reusability.
On top of those classes we have decided to put a WCF layer, so you can expose the method as a web method. If an activity needs data, then it will access a entity service via WCF. To make the activities useful for the business we put them in a class which we have called processes ( a process layer). A process contains one or more activities and is able to call other processes and activities aren’t allowed to call processes or other activities. On top of each process we have decided to put a WCF so the UI can access them.

So it’s pretty close to what you wrote about in the Microsoft Architecture Journal except that we don’t have direct call to the entity services, we wrap it up in an activity before the call, which is wrapped in a WCF-host. Much like the definitions in Ontology and Taxonomy of Services in a Service-Oriented Architecture

I would love to hear your comments and thoughts about this architecture.

With thanks, Ingo

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Additional References:

• Ontology and Taxonomy of Services in a Service-Oriented Architecture
• Udi’s Architecture Journal article on Autonomous Services
  
• Podcast on how to structure .NET solutions and components
• Blog post covering a discussion on Entity Services

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