Using coordination contracts for flexible adaptation to changing business rules

We report on the use of coordination contracts, presented at the previous two IWPSE workshops, in a project for a credit recovery company. We have designed and implemented a framework that allows users to define several business rules according to predefined parameters. However, some rules require changes to the services provided by the system. For these, we use coordination contracts to intercept the calls to the underlying services and superpose whatever behaviour is imposed by the business rules applicable to that service. Such contracts can be added and deleted at run-time. Hence, our framework includes a configurator that, whenever a service is called, checks the applicable rules and configures the service with the given parameters and contracts, before proceeding with the call. Based on our experience, we put forward the position that coordination contracts facilitate the evolution of the system in order to accomodate new business rules that change the "normal" behaviour of the provided system's functionalities.