Shopping Cart Metaphor

Your key objects are "customer" (a party who buys from you) "items" (individual things to buy), "shopping cart" (a collection of items associated with a specific customer).

What other objects -- "checkout manager"?

A "credit card" object comes to mind ;-)

Aha! Payment! What object is responsible for accepting payment?

See ProvenSystemMetaphors, GenericBusinessFrameworkUnobtainable

CategoryMetaphor