Workflow modeling

[achimr]

-- Most importantly: The API does not define a workflow. It seems to provide commands one can use in various scenarios.But this cannot work as a standard. For example a client cannot write his side of the process if there is not a fix set of operation that is expected for all transactions. So the claim that one client can simply switch provider if they implement the API is (for now) bogus: they would have to adapt how they call the API to switch to a new provider. Potentially they would have to call the API in different ways if they work with different providers. Don't take me wrong: I'm all for a standard API. But just defining an API is not going to make it useable. We need to define the sequences of the transactions too. The same client application should be able to just change the URL of the server to switch provider or work with several. (reported by Yves Savourel)

The recently added HATEOAS links provide for a means of self-description describing possible follow-up actions. Could this be enough?