Migration of a Chosen Architectural Pattern to Service Oriented ...

Chapter 5. Guidelines 110Problem The same business rules are applied in many different services.This may lead to redundancy and problem with maintenance of the changes.ContextA System uses many rules across services.Forces(a) Rules may change over time(b) New rules may be added(c) Outdated rules may be removed(d) One rule may be used by many servicesSolution Business rules are stored and accessible through dedicated entitieslike business rules services.Result Context The application has unified access and storage of businessrules. The rules are easy to update and access.9. Name Inventory EndpointProblem An inventory may contain several services providing functionalitythat might be used outside the inventory. Services accessing the inventoryfrom outside should not know structure of the inventory and itsfunctionality. The access also needs to be secured.ContextAn application exposes some of its services to external services.Forces(a) The services that can potentially access the inventory are not known.(b) Structure of the inventory needs to be hidden.(c) The functionality of the inventory needs to be limited.(d) Access to the inventory needs to be secured.Solution Inventory Endpoint establishes an entry point for external serviceconsumers. Each customer accessing service repository, access the endpointand receives information from the endpoint. Capabilities of endpointscan be extended by for instance direct / brokered authentication. A singleInventory can have more than one endpoint.