I'm having trouble figuring out how to drive the design of a class. I'm hoping I can get a hint or two from the more experienced BDDers on this list.

I'm writing an adapter class that sits between a 3rd party library and my business logic. I would like to extract some information from objects available from the 3rd party lib and covert them into ruby objects. My desire is to insulate my ruby business logic from changes in the 3rd party library by putting all of this conversion code into a single adapter class (and some related "event" classes).

Using BDD techniques I have created a pretty simple interface to the adapter class. So far the adapter class has two main public methods (plus a bunch of accessors to allow the dependency injection).

#discover_instruments
- this method calls into the 3rd party library and pulls out the 3rdPartyInstrument object and stores it off for further manipulation

#save_components
- this method permanently saves the 3rdPartyInstrument if it is a FUTURE, or if it is a COMBINATION it iterates through each sub-3rdPartyInstrument and saves it off

Using mocks and ruby's brain-dead simple support for dependency injection I have been able to mock out and verify this behavior.

Now I need to add another public method which I will call #generate_internal_instruments. What I would like this method to do is iterate through my #components and create two related objects. Object one will be my RubyInstrument class (called something else, but this will suffice) and a second is a RubyInstrumentCreationEvent. The intention is to pass the 3rdParty component to RubyInstrumentCreationEvent.new(component) where it will extract all salient details from the 3rdParty component (again, this is for insulating the business logic from knowing this 3rd Party lib). Then I will pass this RubyInstrumentCreationEvent to RubyInstrument.new (or RubyInstrument.build) where it will finish the construction of itself.

Ideally, all of these steps would be private to the Adapter class and would expose a single public interface called #build. All of these public methods exist solely so I can test these specific behaviors.

Any suggestions on how to accomplish my goals? Is my difficulty pointing at a code smell that I am not detecting?

cr

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