Design of composable proxy filters for heterogeneous mobile computing

RAPIDware is a collection of software design techniques for constructing adaptive middleware to support collaborative computing. The paper describes an experimental study in the design of adaptive proxy services for resource-limited mobile hosts. The approach is based on detachable Java I/O streams, which enable proxy filters and transcoders to be dynamically inserted, deleted and reordered on a given data stream. Unlike conventional Java I/O streams, detachable streams can be stopped, disconnected, reconnected, and restarted. As such, they provide the "glue" needed to support the dynamic composition of proxy services. The operation and implementation of detachable streams are described, followed by a discussion of their use in demand-driven forward error correction services for wireless hosts.