Julián Grigera

Mockup-Driven Development: Providing agile support for Model-Driven Web Engineering

Context: Agile software development approaches are currently becoming the industry standard for Web Application development. On the other hand, Model-Driven Web Engineering (MDWE) methodologies are known to improve productivity when building this kind of applications. However, current MDWE methodologies tend to ignore important aspects of Web Applications development supported by agile processes, such as constant customer feedback or early design of user interfaces. Objective: In this paper we analyze the difficulties of supporting agile features in MDWE methodologies. Then, we propose an approach that eases the incorporation of well-known agile practices to MDWE. Method: We propose using User Interface prototypes (usually known as mockups) as a way to start the modeling process in the context of a mixed agile-MDWE process. To assist this process, we defined a lightweight metamodel that allows modeling features over mockups, interacting with end-users and generating MDWE models. Then, we conducted a statistical evaluation of both approaches (traditional vs. mockup-based modeling). Results: First we comment on how agile features can be added to MDWE processes using mockups. Then, we show by means of a quantitative study that the proposed approach is faster, less error-prone and still as complete as traditional MDWE processes. Conclusion: The use of mockups to guide the MDWE process helps in the reduction of the development cycle as well as in the incorporation of agile practices in the model-driven workflow. Complete MDWE models can be built and generated by using lightweight modeling over User Interface mockups, and this process suggests being more efficient, in terms of errors and effort, than traditional modeling in MDWE.

Personalized Web Accessibility using Client-Side Refactoring

According to W3C accessibility standards, most Web applications are neither accessible nor usable for people with disabilities. Developers often solve this problem by building separate accessible applications, but these applications are seldom usable and typically offer less functionality than the original. Another common solution is to maintain a single application, but create an accessible view by applying on-the-fly transformations to each requested page-a solution that rarely suits all audiences. A third solution is described here: let users improve Web accessibility in their client browsers through interface refactorings, which offer many customized, accessible views of a single application.

Capture and evolution of web requirements using webspec

Developing Web applications is a complex and time consuming process that involves different kind of people, ranging from customers to developers. Requirement artefacts play an important role as they are used by these people to perform their daily activities. However, state of the art in requirement management for Web applications disregards valuable features that tend to improve the development process, such as quick validation during elicitation, automatic requirement validation on the final application and useful change management support. To tackle these problems we introduce WebSpec, a requirement artefact for specifying interaction and navigation features in Web applications. We show its use through the development of an example application in the social networking area, and its implementation as an Eclipse plugin.

Towards Agile Model-Driven Web Engineering

The increasing growth of the Web field has promoted the development of a plethora of Model-Driven Web Engineering (MDWE) approaches. These methodologies share a top-down approach: they start by modeling application content, then they define a navigational schema, and finally refine the latter to obtain presentation and rich behavior specifications. Such approach makes it difficult to acquire quick feedback from customers. Conversely, agile methods follow a non-structured, implementation-centered process building software prototypes to get immediate feedback. In this work we propose an agile approach to MDWE methodologies (called Mockup-Driven Development, or MockupDD) by inverting the development process: we start from user interface mockups that facilitate the generation of software prototypes and models, then we enrich them and apply heuristics in order to obtain software specifications at different abstraction levels. As a result, we get an agile prototype-based iterative process, with advantages of a MDWE one.

MockAPI: an agile approach supporting API-first web application development

In the last years, agile development methodologies have been widely adopted. However, they still lack support for API requirements while, at the same time, public RESTful APIs are fueling a rapid growth of web applications providing services built on other services. On the other hand, whereas Model-Driven Development techniques successfully increase the productivity in the development of data-intensive web applications, they lack the agility required when developing heterogeneous web applications with frequent requirement changes. In this paper we introduce MockAPI, an approach based on annotating user interface mockups that combines the advantages of agile approaches and Model-Driven Development. We introduce a metamodel for annotations and demonstrate how to derive running API prototypes as starting point for agile development. RESTful API best practices and API-first development are introduced into the agile process. The MockAPI approach defines a set of constraints to accelerate the development of web applications. We also show the results of a brief validation applying MockAPI to popular web sites.

Automatic detection of usability smells in web applications

Abstract Usability assessment of web applications continues to be an expensive and often neglected practice. While large companies are able to spare resources for studying and improving usability in their products, smaller businesses often divert theirs in other aspects. To help these cases, researches have devised automatic approaches for user interaction analysis, and there are commercial services that offer automated usability statistics at relatively low fees. However, most existing approaches still fall short in specifying the usability problems concretely enough to identify and suggest solutions. In this work we describe usability smells of user interaction, i.e., hints of usability problems on running web applications, and the process in which they can be identified by analyzing user interaction events. We also describe USF, the tool that implements the process in a fully automated way with minimum setup effort. USF analyses user interaction events on-the-fly, discovers usability smells and reports them together with a concrete solution in terms of a usability refactoring, providing usability advice for deployed web applications.

A Modular Architecture for Context Sensing

Due to the technological evolution, context-aware computing is slowly moving from dream to reality. These applications heavily rely in sensing the users environment and abstracting this information to perform high-level adaptation. While technological issues have been mostly addressed, sensing software is usually built in a handcrafted way, which turns into building ad-hoc solutions for every new application. To solve this problem, we consider that context sensing should be regarded as a software engineering problem and not a simple implementation issue. In this paper we present a software architecture for dealing with context-sensing aspects in a high-level modular way. We show that by using this approach, evolution issues typical of mobile wireless software can be managed easily by replacing or composing software modules without compromising performance.

From interface mockups to web application models

The process of modeling and implementing Web applications has been successfully improved by the use of Model-Driven Web Engineering (MDWE) methodologies. However, because of their traditional process models, these methodologies delay the generation of application prototypes until all design aspects (e.g. domain and navigation) are completed. These aspects are crucial for developers but not for customers, who are interested in viewing parts of the application running as early as possible. In this paper we introduce a novel model driven approach that starts from user interface specifications, using mockups to derive concrete presentation implementations -- we call it Mockup-Driven Development or just MockupDD. Then, by using lightweight enrichments and applying heuristics over these models, we show how we obtain navigation and content specifications in the context of different MDWE methods.

A flexible tool suite for change-aware test-driven development of web applications

Though Web Applications development fits well with Test-Driven Development, there are some problems that hinder its success. In this demo we present a tool suite to improve TDD; the suite supports the representation of web requirements using a domain-specific language and the automatic generation of interaction tests among others.

Assessing refactorings for usability in e-commerce applications

Refactoring has been reported as a helpful technique to systematically improve non-functional attributes of software. This paper evaluates the relevance of refactoring for improving usability on web applications. We conducted an experiment with two replications at different locations, with subjects of different profiles. Objects chosen for the experiment were two e-commerce applications that exhibit common business processes in today’s web usage. Through the experiment we found that half of the studied refactorings cause a significant improvement in usability. The rest of the refactorings required a post-hoc analysis in which we considered aspects like user expertise in the interaction with web applications or type of application. We conclude that, when improving quality in use, the success of the refactoring process depends on several factors, including the type of software system, context and users. We have analyzed all these aspects, which developers must consider for a better decision support at the time of prioritizing improvements and outweighing effort.