Formalizing the functional model within object-oriented design

The data flow diagram (DFD), originally introduced for structured design purposes, depicts the functions that a system or a module should provide. The objective of a software system is to implement specific functionalities. The function-oriented decomposition strategy of DFDs in the conventional design process for structured design conflicts with the spirit of object-orientation. So far, there is no object-oriented method that has successfully integrated DFDs into the object-oriented development process. In this paper, we demonstrate how DFDs can be modified in order do be integrated into object-oriented development. The Object Modeling Technique (OMT) is used as the context for object-oriented development. In addition, a set of formalization rules are proposed to provide formal semantics for DFDs in order to integrate the functional model with the other two models of OMT, namely, the object and dynamic models, in terms of the underlying formal semantics.