Composability for software components: an approach based on the Whole-Part theory

Software components differ from ordinary software parts in the sense that they own composition potentialities, commonly named composability or compositionality. The lack of influence on component-based software engineering (CBSE), of reputable and recognized theories, somehow precludes for having comprehensive views and contributions on what composability really is. This paper is grounded on the Whole-Part theory, broadly used in other domains as ontology, knowledge engineering, and more recently, object modeling. However, the use of this theory in CBSE remains low. We on purpose formalize a special kind of composability for components operating on the same deployment node. The foundation of our approach is encapsulation of sub-components by components, emergent and resultant properties for components with regard to their sub-components and finally, state and lifetime dependencies. We lay down a general-purpose framework for designing components that truly possess composition potentialities, based on the fact that relationships between components and sub-components are highly coercive.