Damiano Distante

Speaking a common language: a conceptual model for describing service-oriented systems

The diffusion of service-oriented computing is today heavily influencing many software development and research activities. Despite this, service-oriented computing is a relatively new field, where many aspects still suffer from a lack of standardization. Also, the service-oriented approach is bringing together researchers from different communities or from organizations having developed their own solutions. This introduces the need for letting all these people communicate with each other using a common language and a common understanding of the technologies they are using or building. This paper proposes a conceptual model that describes actors, activities and entities involved in a service-oriented scenario and the relationships between them. While being created for a European project, the model is easily adaptable to address the needs of any other service-oriented initiative.

Model-driven development of web applications with UWA, MVC and JavaServer faces

This paper presents a model-driven approach to the development of web applications based on the Ubiquitous Web Application (UWA) design framework, the Model-View-Controller (MVC) architectural pattern and the JavaServer Faces technology. The approach combines a complete and robust methodology for the user-centered conceptual design of web applications with the MVC metaphor, which improves separation of business logic and data presentation. The proposed approach, by carrying the advantages of Model-Driven Development (MDD) and user-centered design, produces Web applications which are of high quality from the users point of view and easier to maintain and evolve.

Refactoring for Usability in Web Applications

Refactoring a Web applications design structure can improve its usability. Characterizing each refactoring according to the usability factor it improves and the bad usability smells it targets can further clarify its intent.

Transparent interface composition in web applications

In this paper we present an approach for oblivious composition of Web user interfaces, particularly for volatile functionality. Our approach, which is inspired on well-known techniques for advanced separation of concerns such as aspect-oriented software design, allows to clearly separate the design of the cores interface from the one corresponding to more volatile services, i.e. those that are offered for short periods of time. Both interfaces are oblivious from each other and can be seamlessly composed using a transformation language. We show that in this way we simplify the applications evolution by preventing intrusive edition of the interface code. Using some illustrative examples we focus both on design and implementation issues, presenting an extension of the OOHDM design model which supports modular design of volatile functionality.

A comprehensive design model for integrating business processes in web applications

Web applications have evolved from simple read-only websites to complex data- and operation-intensive systems. The main goal of this kind of application is to provide the users with services that assist them in carrying out activities according to a given set of business rules. The addition of transactions to modern web applications poses new challenges, such as managing the interplay between business process execution and navigation, and improving the users experience in accessing the services that the web application offers. This paper presents a comprehensive design model for integrating business processes in web applications. The model is based on UWAT+, an extended and revised version of the Ubiquitous Web Applications (UWA) Transaction Design model for designing web transactions. UWAT+ makes it possible to design web application transactions according to the users perspective and to integrate the web transaction design with the information and navigation design of the web application.

Model Refactoring in Web Applications

Refactoring has been growing in importance with recent software engineering approaches, particularly agile methodologies, which promote continuous improvement of an applications code and design. Web applications are especially suitable for refactoring because of their rapid development and continuous evolution. Refactoring is about applying transformations that preserve program behavior. Code refactorings apply transformations to the source code while model refactorings apply to design models, both with the purpose of increasing internal qualities like maintainability and extensibility. In this paper we propose Web model refactorings as transformations that apply to the design models of a Web application. Particularly, we define refactorings on the navigation and presentation models, and present examples. Since changing these models impacts on what the user perceives, the intent of Web model refactorings is to improve external qualities like usability. They may also help to introduce Web patterns in a Web application.

Recovering conceptual models from web applications

This paper proposes a reverse engineering approach for abstracting conceptual user-centered models from existing Web applications to re-document them at a high level of abstraction and from a user perspective.The recovered models are specified by referring to the Ubiquitous Web Application (UWA) design methodology. UWA models are able to describe the structure of the application contents, the semantic relations among contents, the different views on contents the application offers to users, and the navigation paths and the navigation nodes used to present contents to users.The approach exploits existing reverse engineering methods and tools to extract fine grained structural information from the analyzed applications and abstracts UWA models from them.The architecture of a tool to support the reverse engineering approach is described and the results from some preliminary experiments are discussed.

Incremental quality improvement in web applications using web model refactoring

Web applications must be usable and accessible; besides, they evolve at a fast pace and it is difficult to sustain a high degree of external quality. Agile methods and continuous refactoring are well-suited for the rapid development of Web applications since they particularly support continuous evolution. However, the purpose of traditional refactorings is to improve internal quality, like maintainability of design and code, rather than usability of the application. We have defined Web model refactorings as transformations on the navigation and presentation models of a Web application. In this paper, we demonstrate how Web model refactorings can improve the usability of a Web application by using a mature quality evaluation approach (WebQEM) to assess the impact of refactoring on some defined attributes of a Web product entity. We present a case study showing how a shopping cart in an e-commerce site can improve its usability by applying Web model refactorings.

A model-driven approach for the fast prototyping of web applications

This paper presents an approach for the model-driven fast prototyping of Web applications. The approach exploits well known Model-Driven Engineering frameworks and technologies, such as Eclipse EMF, GMF, and Xpand, to enable the design of a Web application and the automatic generation of the code artifacts implementing a ready to deploy prototype of it. The approach allows to effortlessly and quickly carry out a modeling-generation-validation process in order to validate and refining the design of a Web application before actually implementing it. The paper describes the approach and the process followed to define it, the supporting tools and the technologies used to develop them, and the results from a case study of designing and generating the prototype of a Web application for on-line note taking and sharing. The process and the technologies used to develop the proposed approach can be reused to develop a fast prototyping approach for a different design model and a different target technology platform.

The RE-UWA approach to recover user centered conceptual models from Web applications

Large-scale Web Applications, especially those intended to publish contents and provide information to its users, are by nature subject to continuous and fast changes. This often means fast obsolescence of the design documentation and a lot of effort required to comprehend the application when performing maintenance and evolution tasks. This paper presents a reverse engineering approach for Web Applications enabling the semi-automatic recovery of user-centered conceptual models describing, from a user perspective, key aspects, such as the delivered contents and navigational paths. The abstracted models are formalized according to the Ubiquitous Web Applications (UWA) design methodology, but any other design method for Web Applications could be used instead. The paper describes the recovery process, a tool developed to support the process, and the results from a case study conducted to validate the approach on a set of real world Web Applications.