A Polymorphism Implementation of Web Services for Context Adaptation and Performance

Context aware applications in Ubiquitous Computing (UC) require the dynamic adaptation to the context and the interoperability across heterogeneous platforms, as a distributed system. Service-oriented Architecture (SOA) enables the dynamic adaptation through using loosely-coupled services, and it also supports the interoperability through using XML messaging. For the adaptation, the orchestration service of SOA implements the adaptation steps inside the source code with some APIs. It also causes more messaging between services, but the XML messaging is the bottleneck of the performance. However, UC requires the frequent messaging between various sites within its boundary according to the frequent changes of the context. Finally, the context adaptation causes lots of messaging, and the messaging causes the decrease of the execution performance. This paper proposes a polymorphism implementation of SOA services to satisfy both of the context adaptation and the execution performance. It also measures how well the polymorphism model satisfies them with an implementation of J2EE.