--- In [email protected], Michael Poulin <[EMAIL PROTECTED]> wrote: > > I would like to comment two points in Rob's note: > > 1) "The UI isn't a service (nor a collection of services). It performs all the complex things it needs to do to provide the rich experience users need. Pagination is probably one of those things." > > - sounds like a magic while it has quite simple concept: ANY UI is a combination of Business Service Interface and User Experience.
Right. It's a service consumer combined with the components that implement the UI. I didn't intend to make it sound like voodoo. I contend that a UI is not a service in the context of an SOA service provider. > This means each UI view (page, window,...) combines well-known > though complex things. Pagination clearly relates to the Business > Service Interface return which is constrained by User Experience > and visualisation conditions, in particular, how many entries > may/should be displayed at once. My experience tells me that > pagination can be perfectly implemented as a service (and it is > done many times in the area of distributed computing) Stateless principles indicate that the service provider should not keep track of the page position. This means the UI must track it. As you imply, the service provider of "getList" might support inputs such as offset and maxcount. Or, the service provider might do nothing at all to help with pagination and the UI must implement a scheme to manage the pages. There are pros and cons to both approaches. > > 2) "I agree that a UI will generally be guided more by other > principles rather than by SOA principles. The UI generally will be > guided by SOA principles as a service consumer, not as a service > provider. A UI is not a "non-SOA thing" " > > - sure, a UI is generally guided by other principles than by SOA > principles - due to the User Experience requirements. Yes, UI is > better be Service Consumer friendly (nevertheless, provided by the > Service Provider or an intermediary). "Service consumer friendly?" I don't understand what you're saying. The UI is a service consumer. > - interesting expression - "A UI is not a "non-SOA thing"". > Arguing about this means arguing about whether a business service > is a SOA-thing. Is a UI totally covered by SOA concepts? My answer > is NO, but there is no mystique in it. Suhayl indicated that he feels the UI and reporting tools are "non- SOA things." I simply pointed out that I believe they are, but perhaps my wording wasn't to your liking? -Rob
