Neville Churcher

Comments on "A metrics suite for object oriented design

A suite of object oriented software metrics has recently been proposed by S.R. Chidamber and C.F. Kemerer (see ibid., vol. 20, p. 476-94, 1994). While the authors have taken care to ensure their metrics have a sound measurement theoretical basis, we argue that is premature to begin applying such metrics while there remains uncertainty about the precise definitions of many of the quantities to be observed and their impact upon subsequent indirect metrics. In particular, we show some of the ambiguities associated with the seemingly simple concept of the number of methods per class. The usefulness of the proposed metrics, and others, would be greatly enhanced if clearer guidance concerning their application to specific languages were to be provided. Such empirical considerations are as important as the theoretical issues raised by the authors. >

Towards a conceptual framework for object oriented software metrics

The development of software metrics for object oriented (OO) languages is receiving increasing attention. We examine the reasons why this is a much more challenging problem than for conventional languages. It seems premature to develop and apply OO metrics while there remains uncertainty not only about the precise definitions of many fundamental quantities and their subsequent impact on derived metrics, but also a lack of qualitative understanding of the structure and behaviour of OO systems. We argue that establishing a standard terminology and data model will help provide a framework for both theoretical and empirical work and increase the chances of early success. One potential benefit is improvement of the ability to perform independent validation of models and metrics. We propose a data model and terminology and illustrate the importance of such definitions by examining the seemingly straightforward concept of the number of methods per class. We discuss the implications of ambiguities in definitions for a suite of metrics which has recently been proposed. Preliminary results from our analysis of industrial systems are presented.

An extensible framework for collaborative software engineering

The size, complexity and duration of typical software engineering projects means that teams of developers will work on them. However, with the exception of version control systems, the editors, diagrammers and other tools used will generally support only a single user. We present an architecture for bringing to software engineering development environments the advantages of awareness of the presence, intentions, and actions of others. Thus far, the applications of such facilities have been primarily in simple computer supported cooperative work (CSCW) tools, such as shared whiteboards, where the corresponding artifacts, unlike those of software engineering, are typically both simple and transient. We describe our implementation of the architecture and prototype tools and illustrate the benefits of providing support for real-time collaboration between developers located anywhere on the Internet. We also describe how our architecture, which is based on a parse tree representation of artifacts, may be extended readily to include new tools, languages, and notations or be customised to provide new awareness mechanisms.

Object oriented metrics: precision tools and configurable visualisations

Software metrics are a valuable tool in helping software engineers to develop large, complex software systems. However, it is vital that transparency and precision are maintained at all stages. We contend that without grammars we cannot define metrics rigorously, without transparent and powerful parsing tools we cannot collect data accurately and without flexible configurable visualisation we cannot exploit the full potential of our data. We report the development of JST, a semantic analyser for Java, and show how it is incorporated into our pipeline-based approach to metrics collection and visualisation. We describe a new visualisation, class clusters, which not only demonstrate the data generated by our tools but also illustrate the value of 3D virtual worlds for visualising software metrics.

Do your eyes give it away? using eye tracking data to understand students' attitudes towards open student model representations

There is sufficient evidence to show that allowing students to see their own student model is an effective learning and metacognitive strategy. Different tutors have different representations of these open student models, all varying in complexity and detail. EER-Tutor has a number of open student model representations available to the student at any particular time. These include skill meters, kiviat graphs, tag clouds, concept hierarchies, concept lists, and treemaps. Finding out which representation best helps the student at their level of expertise is a difficult task. Do they really understand the representation they are looking at? This paper looks at a novel way of using eye gaze tracking data to see if such data provides us with any clues as to how students use these representations and if they understand them.

Realtime Conferencing in GIS

Most GIS applications support multi-user facilities only to the extent that many people can access the same data as if they were each the only user. For collaborative work, it is beneficial for participants to be able to browse, annotate and query the data with full awareness of each other. Groupware or Computer Supported Cooperative Work (CSCW) provides support for groups of people to participate in virtual conferences from different locations. We demonstrate the advantages to be gained by applying CSCW to GIS and describe GroupARC, an application enabling GIS data to be simultaneously browsed, queried and annotated by many participants.

CodeRank: a new family of software metrics

The concept of pagerank has proved successful in allowing search engines to identify important pages in the World Wide Web. In this paper, we describe the application of the pagerank concept to the domain of software in order to derive a new family of metrics, CodeRank, which captures aspects of software not readily obtainable from other metrics. We have implemented a tool, CODERANKER, to compute values of CodeRank metrics using a full semantic model which we have developed. We present some results and discuss the use of CodeRank metrics in their interpretation

In Situ Software Visualisation

Software engineers need to design, implement, comprehend and maintain large and complex software systems. Awareness of information about the properties and state of individual artifacts, and the process being enacted to produce them, can make these activities less error-prone and more efficient. In this paper we advocate the use of code colouring to augment development environments with rich information overlays. These in situ visualisations are delivered within the existing IDE interface and deliver valuable information with minimal overhead. We present CoderChrome, a code colouring plug-in for Eclipse, and describe how it can be used to support and enhance software engineering activities.

A user evaluation of synchronous collaborative software engineering tools

Collaborative software engineering (CSE) is a rapidly growing field. Tools such as IDEs are now beginning to incorporate new collaborative features. We have developed several real-time CSE tools which support fine-grained collaboration. In this paper we present an empirical evaluation to investigate the potential benefits of our tools for collaborative source code development. Our results show that for the two typical types of collaborative programming scenarios studied, users of CSE tools achieve task completion rates at least twice as fast as those obtained from their single-user counterparts. Additionally, participants indicated strong support for the concept of CSE tools. These results encourage us to continue developing our CSE tools, and to investigate their use in other software engineering contexts.

Theme-based literate programming

The source code for computer programs is destined to be read by compilers and consequently its internal structure is heavily constrained. The compiler neither knows nor cares about such things as a programs internal structure, the relationships between its components and their specifications, the way design patterns are instantiated, the best way to explain its algorithms or how it is intended to be used. People do. Literate programming (LP) was invented by Donald Knuth as a way to address such problems. The idea is appealing but LP has not been adopted widely: the lack of good tools, difficulties with object-oriented languages and the limitations of a single psychological order are among the reasons. We report the development of theme-based literate programming (TBLP). Themes are extremely flexible: they may be aimed at particular reader groups or represent aspects of the program. Features of TBLP include an extended chunk model which accommodates a richer variety of types, an extended connection model which allows chunks to be threaded together into multiple themes, an enhanced processing model which generalises tangling and weaving and a chunk-level version management system. XML is used to represent the web structure and XML-based technologies such as XSLT are used in processing. This provides flexibility and extensibility, allowing users to define new chunk types. An application which implements TBLP is presented and the integration of TBLP with software engineering processes is discussed.