Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.

Web application design is a broad term that refers to any aspect of designing a Web application, including designing Web interfaces to data. There are a number of commercial software tools available that employ various techniques for implementing Web access to databases. However, these techniques apply only to portions of Web application implementation and lack a common design paradigm. We believe that defining an approach to designing and implementing Web applications based on views, frameworks, and patterns allows us to extend an object-oriented design representation and develop reusable and extensible design solutions for a class of Web applications in which the concerns are separated. The major contribution of this thesis is the development of a new approach to designing Web applications, producing the following visible contributions: a model for Web applications based upon a separation of concerns using views; a framework for system elements so that object-oriented design patterns can be used to build the application; a reusable design approach so that many Web applications can be built around the same framework; a coherent and organized framework representation using extended UML; and an implementation approach that can be implemented on a number of different platforms using a range of software and tools. In support of this solution, this thesis shows the design and implementation of a proof-of-concept Web application using this design technique. We believe that the approach to Web application design promoted in this thesis has proven itself useful in a practical way for the case studies discussed herein and points the way to a wider range of design and implementation possibilities.

Web application design is a broad term that refers to any aspect of designing a Web application, including designing Web interfaces to data. There are a number of commercial software tools available that employ various techniques for implementing Web access to databases. However, these techniques apply only to portions of Web application implementation and lack a common design paradigm. We believe that defining an approach to designing and implementing Web applications based on views, frameworks, and patterns allows us to extend an object-oriented design representation and develop reusable and extensible design solutions for a class of Web applications in which the concerns are separated. The major contribution of this thesis is the development of a new approach to designing Web applications, producing the following visible contributions: a model for Web applications based upon a separation of concerns using views; a framework for system elements so that object-oriented design patterns can be used to build the application; a reusable design approach so that many Web applications can be built around the same framework; a coherent and organized framework representation using extended UML; and an implementation approach that can be implemented on a number of different platforms using a range of software and tools. In support of this solution, this thesis shows the design and implementation of a proof-of-concept Web application using this design technique. We believe that the approach to Web application design promoted in this thesis has proven itself useful in a practical way for the case studies discussed herein and points the way to a wider range of design and implementation possibilities.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

The complexity of Web sites are increasing and transforming into Web applications that contain business logic, interactivity, transaction handling and states. This phenomenon forces the Web developers to adapt more traditional software engineering techniques to keep the Web applications error free, maintainable, reusable, well documented etc. Many Web developers do not use any engineering techniques at all and design mainly to create as fashionable applications as possible with no regards on the application?s functionality. This results in applications that are hard to maintain and with poor functionality. The purpose with this thesis was to see if the use of a more traditional software engineering technique, namely the Unified Modeling Language with the newly added Web Application Extension, resulted in a Web application with good design regarding the maintainability of the application. To investigate the maintainability of an application, the maintainability was further divided into three sub criteria: extensibility, reusability and documentation. These three criteria were then applied on a case study were a Web application was designed. From the analysis of the final design, using the three criteria, the maintainability was derived. The result of the entire investigation showed that the UML WAE had a good support for extensibility, fair support for reusability and very good support for documentation. From these results the main conclusion was derived, that the use of UML WAE resulted in good design regarding the maintainability. However, the result is limited to our case study and the design created in that case. The result may have been different if the three criteria had been applied on a different case. Another aspect to consider is that the quality of a design is often dependent on the knowledge of the persons that carry out the design.

Since Web applications are very complex, compared to traditional client/server applications, Web application design with the UML can be obtrusively hard for a modeller. The grounds are that the UML does not define the correct semantics to be able to visualize a web application correctly. This is a qualitative reduction study where we have used interviews and our own experience during the redesign of a UML-modelled e-commerce application with WAE-UML. Using the flow of a case study we have tried to see if we can improve three quality attributes of a complete design. Stakeholder communication reflects the need of unambiguous design artefacts that are easy to understand and that mediate the real message of the use-case. The condition of the design artefacts should provide artefacts that resemble reality and that not are misleading and provide for verification and validation of the requirements. The last attribute maintainability should provide means for easy maintenance and updates. We found that WAE-UML can improve these quality attributes in a design but the impact it has on them is dependent on two major aspects. The first aspect concerns the designers’ judgment of detail in a design. A detailed design can be good considering requirements and use-case traceability and verification, but prohibit communication. Maintainability can also be improved in a detailed design because the diagrams are less abstract and a truer picture of the application. The second aspect is that it depends on the knowledge possessed of the semantics by the people in contact with the design documents. Due to the time aspect the people working in the industry that we interviewed were reluctant to modelling a Web application at all. They thought it would take a long time to learn WAE-UML but also for executing a design phase. / Contact e-mail: miga02@student.bth.se, hean01@student.bth.se