Pieter Van Gorp

Towards automating source-consistent UML refactorings

With the increased interest in refactoring, UML tool vendors seek ways to support software developers in applying a (sequence of) refactoring(s). The problem with such tools is that the UML metamodel – on which their repository is based – is inadequate to maintain the consistency between the model and the code while one of them gets refactored. Therefore, we propose a set of minimal extensions to the UML metamodel, which is sufficient to reason about refactoring for all common OO languages. For instance, by specifying pre- and postconditions in OCL, we are able to compose primitive refactorings, verify preservation of program behavior, and trigger refactorings based on code smells. This way, we provide future MDA tools with the ability to improve existing UML designs, yet keeping them in synch with the underlying code base.

SHARE: a web portal for creating and sharing executable research papers

Abstract This paper describes how SHARE (Sharing Hosted Autonomous Research Environments) satisfies the criteria of the Elsevier 2011 Executable Paper Grand Challenge. This challenge aims at disseminating the use of systems that provide reviewers and fellow scientists a convenient way to reproduce computational results of research papers. This can involve among others the calculation of a number, the plotting of a diagram, the automatic proof of a theorem or the interactive transformation of various inputs into a complex output document. Besides reproducing the literate results, readers of an executable paper should also be able to explore the result space by entering different input parameters than the ones reported in the original text. SHARE is a web portal that enables academics to create, share, and access remote virtual machines that can be cited from research papers. By deploying in SHARE a copy of the required operating system as well as all the relevant software and data, authors can make a conventional paper fully reproducible and interactive. Shared virtual machines can also contain the original paper text— when desirable even with embedded computations. This paper shows the concrete potential of SHARE-based articles by means of an example virtual machine that is based on a conventional research article published by Elsevier recently. More generally, it demonstrates how SHARE has supported the publication workflow of a journal special issue and various workshop proceedings. Finally, it clarifies how the SHARE architecture supports among others the Elsevier challenges licensing and scalability requirements without domain specific restrictions.

Refactoring: current research and future trends

In this paper we provide an detailed overview of existing research in the field of software restructuring and refactoring, from a formal as well as a practical point of view. Next, we propose an extensive list of open questions that indicate future research directions, and we provide some partial answers to these questions.

Using Graph Transformation for Practical Model Driven Software Engineering

Model transformations are one of the core technologies needed to apply OMG’s model-driven engineering concept for the construction of real-world systems. Several formalisms are currently proposed for the specification of these model transformations. A suitable formalism is based on graph transformation systems and graph transformation rules. The chapter provides an overview about the needed concepts to apply graph transformations in the context of model driven engineering and we show the technical feasibility based on several tools and applications.

Transformation of UML Models to CSP: A Case Study for Graph Transformation Tools

Graph transformation provides an intuitive mechanism for capturing model transformations. In the current paper, we investigate and compare various graph transformation tools using a compact practical model transformation case study carried out as part of the AGTIVE 2007 Tool Contest [22]. The aim of this case study is to generate formal CSP processes from high-level UML activity diagrams, which enables to carry out mathematical analysis of the system under design.

Graph and model transformation tools for model migration

We describe the results of the Transformation Tool Contest 2010 workshop, in which nine graph and model transformation tools were compared for specifying model migration. The model migration problem—migration of UML activity diagrams from version 1.4 to version 2.2—is non-trivial and practically relevant. The solutions have been compared with respect to several criteria: correctness, conciseness, understandability, appropriateness, maturity and support for extensions to the core migration task. We describe in detail the comparison method, and discuss the strengths and weaknesses of the solutions with a special focus on the differences between graph and model transformation for model migration. The comparison results demonstrate tool and language features that strongly impact the efficacy of solutions, such as support for retyping of model elements. The results are used to motivate an agenda for future model migration research (including suggestions for areas in which the tools need to be further improved).

Leveraging UML Profiles to Generate Plugins From Visual Model Transformations

Model transformation is a fundamental technology in the MDA. Therefore, model transformations should be treated as first class entities, that is, models. One could use the metamodel of SDM, a graph based object transformation language, as the metamodel of such transformation models. However, there are two problems associated with this. First, SDM has a non-standardized metamodel, meaning a specific tool (Fujaba) would be needed to write transformation specifications. Secondly, due to assumptions of the code generator, the transformations could only be deployed on the Fujaba tool itself. In this paper, we describe how these issues have been overcome through the development of a template based code generator that translates instances of a UML profile for SDM to complete model transformation code that complies to the JMI standard. We have validated this approach by specifying a simple visual refactoring in one UML tool and deploying the generated plugin on another UML tool.

Graph transformation tool contest 2008

This special section is the outcome of the graph transformation tool contest organised during the Graph-Based Tools (GraBaTs) 2008 workshop, which took place as a satellite event of the International Conference on Graph Transformation (ICGT) 2008. The contest involved two parts: three “off-line case studies” which were published before the contest, and to which solutions were submitted and reviewed; and a “live contest” for which the case description was only handed out during the event, and to which solutions had to be constructed during a single afternoon session. Here we briefly sketch the off-line cases, and the setup and topic of the live contest in somewhat more detail. We also evaluate the results of the workshop, and give some recommendations for future editions. Finally, we introduce the research papers appearing in this special section.

Synthesizing object life cycles from business process models

Business process models expressed in UML activity diagrams can specify the flow of stateful business objects among activities. Such business process models implicitly specify the life cycles of those objects. To check the consistency of a business process model with an existing object life cycle or to generate or configure software supporting the business process, these implicit life cycles need to be discovered. This paper presents an approach for synthesizing an object life cycle from a business process model in which the object occurs in different states. The synthesized object life cycles are expressed as hierarchical statecharts. The approach makes implicit life cycles contained inside business process models explicit. The synthesis approach has been implemented using a graph transformation tool and has been applied to case studies.

Transformation Language Integration Based on Profiles and Higher Order Transformations

For about two decades, researchers have been constructing tools for applying graph transformations on large model transformation case studies. Instead of incrementally extending a common core, these competitive tool builders have repeatedly reconstructed mechanisms that were already supported by other tools. Not only has this been counter-productive, it has also prevented the definition of new language constructs independently of a specific transformation tool. Moreover, it has complicated the comparison of transformation languages. This paper describes a light-weight solution to this integration problem. The approach is based on executable transformation modeling using a small UML profile and on higher order transformations. It enables the integration of graph transformation tools such as Fujaba, VMTS and GReAT. The paper illustrates the approach by discussing the contribution of a Copy operator to any of these tools. Other language constructs can be realized similarly, without locking into specific tools.