SCEL: a Language for Autonomic Computing

The autonomic computing paradigm has been proposed to cope with size, complexity and dynamism of contemporary softwareintensive systems. The challenge for language designers is to devise appropriate abstractions and linguistic primitives to deal with the large dimension of systems, and with their need to adapt to the changes of the working environment and to the evolving requirements. We propose a set of programming abstractions that permit to represent behaviors, knowledge and aggregations according to specific policies, and to support programming context-awareness, self-awareness and adaptation. Based on these abstractions, we define SCEL (Software Component Ensemble Language), a kernel language whose solid semantic foundations lay also the basis for formal reasoning on autonomic systems behavior. In this document, we first present the syntax and operational semantics of SCEL. We then demonstrate that adaptation can be naturally modeled in SCEL, and present a simple policy language and its integration with SCEL. Finally, to show expressiveness and effectiveness of SCEL’s design, we present a Java implementation of the SCEL’s programming abstractions and illustrate their use by specifying two case studies from the service provision and robotics domains. ? This work has been partially sponsored by the EU project ASCENS (257414).