Abstract Pricing Model for .NET

High-level abstract model for calculating price of subscriptions and/or other products and services

Each Tariff is composed by a list of Fees. Tariff contains minimal logic and provides unified interface for calculating Fees. Tariff implements Fascade pattern to operate list of Fee objects.

Terminology and main classes

• Tariff is a class representing the main entity the model is going to compare. Tariff, product, service and subscription are hereby considered the same thing. Tariff aggregates a set of fees. Tariff classes are designed to be reused when same pricing model is required, only with different values.
• Fee is is a class that comprises a Tariff - a Tariff has many Fees. Each Fee implement it's own 'Calculate(...). E.g. some fees are based on consumption, while others on fixed periods of time.
• Applying a fee is the process of calculation of cost - really done in IFee.Calculate(...). When Calculate(...) is called on Tariff object it calls Calculate(...) on each Fee and aggregates the result

Common actions

Add a Tariff

To add a new Tariff extend the abstract Tariff class.

Add a Fee

Extend and implement from IFee interface. Use the Fee within a Tariff class.

Change calculation algorithm

Override Calculate(...) from the base abstract Tariff class.

Add features to the model

To add features to the model, like add more unit types or change calculation algorithm, re-implement the ITariff and IFee interfaces. Consumption class is also meant to be extended as needed