Design a shopping cart service

Design a shopping cart service that could be used by any e-store service to store and submit customers purchase requests. Services using your shopping cart service should pay fees as 1% of each purchase order submitted through the shopping cart service. You can make any assumptions you need. However you must clearly state and justify such assumptions. Your answers should clearly include: 1. The context diagram. 2. The service system Architecture. 3. The service system elements showing its inputs, outputs, components, sensors and transformers (i.e. processes). 4. The service operational model showing the different interactions and dataflow diagrams as well as the involved processes models. 5. Realization of the service charge model. (i.e. show how to generate bills for services using the shopping cart service) 6. The data architecture. 7. The exchanged Message formats. 8. The interfaces of the subsystems. 9. WSDL definitions for the shopping cart service. 10. WSDL definitions for any services consumed by the shopping cart service.