Domain models and Metro (was: First discussion - api/implpattern)

Niclas Hedhman niclas at hedhman.org
Tue Oct 5 13:13:58 EDT 2004


On Tuesday 05 October 2004 23:48, David Leangen wrote:

> So essentially, these would be one classe (such as InitialContext) in the
> API that would actually be an implementation class? Or an implementation
> class that would be added to the API doc?

APIs don't have to be free of classes.
The only thing to remember is to keep everything that ends up in the API to an 
absolute minimum. That can't be changed later.

There is a follow up on this problem, that has been irritating Avalon for a 
few years, and that is; Even though you only have interfaces in your API and 
technically speaking could have multple implementations, it is VERY important 
that the API also defines the arguments in and out of methods with a very 
high degree of accuracy. There is even a programming discipline very heavy 
into the 'semantic aspect' of interfaces, and that is called Design By 
Contract.

Cheers
Niclas


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