Re: Responsibilities of ApplicationServices versus DomainServices

Infrastructure service

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On Monday, May 27, 2013, Wim van Gool wrote:

> **
>
>
> Everybody knows ApplicationServices and DomainServices are different and
> have different responsibilities. Yet, I think it would be convenient to
> have a clear list of what things should typically be handled by each
> service-type and what not. I'll kick it off by my own thoughts on the
> matter and hope others will correct me or help me complete the list (or add
> some open questions).
>
> *ApplicationServices* (aka MessageHandlers)
> - Live in the ApplicationLayer.
> - Know about and handle messages of any kind (commands and events,
> external and internal)
> - Never contain any business logic, but delegate to the domain(services)
> for this.
> - Translates message-property values to Domain-instances where required.
> - May have some form of exception-handling to handle/convert exceptions
> raised by the domain.
>
> *DomainServices*
> - Live in the DomainLayer
> - Know nothing about messages - only plain arguments.
> - Primarily used to coordinate several calls to aggregates in one
> transaction, which should be a rather scarce case.
>
> *Remaining questions*:
> - Which service would you use to implement adding/removing aggregates and
> raise the appropriate DomainEvent?
> - Which service would you use to send an email or otherwise call external
> services?
>
>  
>


-- 
Le doute n'est pas une condition agréable, mais la certitude est absurde.