Serfs: Dynamically-bound parameterized components

Parameterization is an effective technique for decoupling design decisions in software. Several languages such as C++ and Ada (and Java and C# more recently) offer language constructs for building parameterized software. Using template or generic constructs, one can postpone committing to specific design choices until the software system is ready for deployment. However, in cases where such choices are influenced by the execution environment, deployment time may not be late enough. Moreover, in the context of software systems that have to satisfy high availability constraints, or are long-running, changes in design choices may be warranted even after deployment. In this paper, we present a design pattern-based methodology for building parameterized components that support dynamic binding of parameters. Moreover, the methodology also supports dynamic re-binding of parameters in the event that such online change is required.