On Distribution of Components in Pi
In: Report Pi-1 of the DFG Project QUAFOS
Essen: University of Essen, Department of Mathematics and Computer Science / Specification of Software System. (1996)
Buchaufsatz / Kapitel / Fach: Wirtschaftswissenschaften
In order to support software qualities like reusability, portability and maintainability, a software architecture has to consist of self-contained components and explicit descriptions of component connections. The Pi language offers adequate means for specification of modular software systems according to this component concept. However, the Pi language as well as the Pi Language Syntaxedior PILS presume all components of the software architecture are available locally and offer no means for specifying aspects related to distribution of components. In this paper we present our concept for extending the Pi language towards distribution of components, which follows the OMG/CORBA standard for distributed, object oriented systems. First we define an additional Pi view, which encapsulates distribution related information of a component - the interaction view. Then we show how the component connection description has to be extended in order to realize remote use relations. Further, we present a model for defining and evaluating non-funtional properties of the component interaction. Our distribution concept will be described informally as well as formally by presenting the Pi syntax extensions. Also, we define the formal semantics of our distribution concept using modular graph grammars.