An Enhanced Composition Model for Conversational Enterprise JavaBeans
When designing applications with Enterprise JavaBeans (EJBs) and more specifically with Stateful Session Beans, a major difficulty (or even an impossibility) is being able to properly transform business models and more precisely UML 2 models, into such component types, while including the expression of their mutual compositions. This contradicts with the spirit of the emerging Model-Driven Architecture (MDA) software engineering paradigm based on the definition of seamless model transformations. In this scope, this paper proposes and describes an appropriate Java library in order to increase the composition power of EJBs. The proposition includes a support for a broadcast communication mode (assimilated to “horizontal composition” in the paper) which is, a priori, incompatible with non reentrance, a key characteristic of EJBs. Besides, “vertical composition” is the counterpart of “horizontal compo-sition”. “Vertical composition” enables the consistent hierarchical combination of composite behaviors and compound behaviors, both being specified and implemented by means of UML 2 State Machine Diagrams.
KeywordsState Machine Composition Model Autonomic Computing Component Instance State Machine Diagram
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