Developing Web Applications with UML and Object-Process Methodology (OPM)
The exponential growth of the Web during the last two decades and its expected spread in the next years has set the stage for the enlarged use of Web applications. Web applications, which can be classified as a hybrid between a hypermedia and an information system, have a relatively simple distributed architecture from the user viewpoint and a more complex dynamic architecture from the designer viewpoint, heterogeneously skilled users whose number is considered unlimited, security and privacy concerns, heterogeneous, up-to-date information sources, and very dynamic behaviors. The existing hypermedia authoring techniques and system development methods can model some of these aspects. UML, which is the industrial standard object-oriented modeling language, uses nine types of diagrams in order to specify system structure, architecture, and functionality. Being object-oriented, UML concentrates on objects and their static relations, while the procedural aspects are suppressed and revealed only through operations of objects and the messages passed among them.
The Object-Process Methodology (OPM) is a holistic approach to the modeling, study and development of systems. It integrates the object-oriented and process-oriented paradigms into a single frame of reference. Structure and behavior, the two major aspects that each system exhibits, co-exist in the same OPM model without highlighting one at the expense of suppressing the other. Due to structure-behavior integration, OPM provides a solid basis for modeling complex systems, such as Web applications.
In order to establish the level of comprehension of a given OPM model and the quality of the models constructed using it, we compared OPM experimentally to an extension of UML. Third year undergraduate information systems engineering students had to respond to comprehension and construction questions about two representative Web application models. The questions related to the system's structure, dynamics, and distribution aspects. We found that OPM is significantly better in modeling the dynamics and distribution aspects of the Web applications, while in specifying their structure, there were no significant differences. In both case studies, the quality of the resulting OPM models was superior.