Jörg P. Wadsack

Towards pattern-based design recovery

A method and a corresponding tool is described which assist design recovery and program understanding by recognising instances of design patterns semi-automatically. The approach taken is specifically designed to overcome the existing scalability problems caused by many design and implementation variants of design pattern instances. Our approach is based on a new recognition algorithm which works incrementally rather than trying to analyse a possibly large software system in one pass without any human intervention. The new algorithm exploits domain and context knowledge given by a reverse engineer and by a special underlying data structure, namely a special form of an annotated abstract syntax graph. A comparative and quantitative evaluation of applying the approach to the Java AWT and JGL libraries is also given.

Tool integration at the meta-model level: the Fujaba approach

Today’s development processes employ a variety of notations and tools, e.g., the Unified Modeling Language UML, the Standard Description Language SDL, requirements databases, design tools, code generators, model checkers, etc. For better process support, the employed tools may be organized within a tool suite or integration platform, e.g., Rational Rose or Eclipse. While these tool-integration platforms usually provide GUI adaption mechanisms and functional adaption via application programming interfaces, they frequently do not provide appropriate means for data integration at the meta-model level. Thus, overlapping and redundant data from different “integrated” tools may easily become inconsistent and unusable. We propose two design patterns that provide a flexible basis for the integration of different tool data at the meta-model level. To achieve consistency between meta-models, we describe rule-based mechanisms providing generic solutions for managing overlapping and redundant data. The proposed mechanisms are widely used within the Fujaba Tool Suite. We report about our implementation and application experiences .

Handling large search space in pattern-based reverse engineering

Large industrial legacy systems are challenges of reverse-engineering activities. Reverse-engineering approaches use text-search tools based on regular expressions or work on graph representations of programs, such as abstract syntax graphs. Analyzing large legacy systems often fail because of the large search space. Our approach to handle large search space in pattern-based reverse engineering is to allow imprecise results in means of false positives. We use the theory of fuzzy sets to express impreciseness and present our approach on the example of recovering associations.

Supporting iterations in exploratory database reengineering processes

Key technologies like the World Wide Web, object-orientation, and distributed computing enable new applications, e.g., in the area of electronic commerce, management of information systems, and decision support systems. Today, many companies face the problem that they have to reengineer pre-existing information systems to take advantage of these technologies. Various computer-aided reengineering tools have been developed to reduce the complexity of the reengineering task. A major limitation of current approaches, however, is that they impose a strictly phase-oriented, waterfall-type reengineering process, with little support for iterations. Still, such iterations often occur in real-world examples, e.g., when additional knowledge about the legacy system becomes available or when the legacy system is modified during an ongoing migration process. In this paper, we present an approach to incremental consistency management that allows to overcome this limitation in the domain of database systems by integrating reverse and forward engineering activities in an intertwined process. The described mechanism is based on a formalization of conceptual schema translation and redesign transformations by graph rewriting rules and has been implemented and evaluated with the Varlet database reengineering environment.

Integration of analysis and redesign activities in information system reengineering

Emerging key technologies like the World Wide Web, object-orientation, and distributed computing enable new applications, e.g., in the area of electronic commerce, management information systems, and decision support systems. Today, many companies face the problem that they have to reengineer pre-existing information systems to take advantage of these technologies. Various computer-aided reengineering tools have been developed to reduce the complexity of the reengineering task. However a major limitation of current approaches is that they impose a strictly phase-oriented waterfall-type reengineering process, without the support for iterations. Still, such iterations often occur in real world examples, e.g., when additional knowledge about the legacy system becomes available or when the legacy system is modified during the migration process. We present an approach to incremental consistency management that allows to overcome this limitation by integrating reverse and forward engineering activities in an intertwined process. The described mechanism is based on a formalization of redesign transformations by graph rewriting rules and has been implemented in the Varlet reengineering environment.

A history concept for design recovery tools

Many tools have been developed for recovering the design of legacy software. Interactively invoked abstraction operations and re-design transformations play a central role in these tools. A limitation of most existing approaches is, however, that they assume a mostly linear transformation process. They provide little support for iteration, recursion and incremental changes during the recovery process. Nevertheless, empirical results suggest that real-world abstraction and reengineering processes are in fact highly iterative. A history mechanism that explicitly maintains dependencies of all performed transformations can overcome this mismatch. Based on our experience with a specialized implementation of such a mechanism, we present a generalized history concept as an add-on to existing tools that support design recovery.

Automated quality analysis of component software for embedded systems

The Java programming language has gained increasing importance for the development of embedded systems. To be cost efficient, such systems have to cope with significant hardware restrictions which result in certain software programming restrictions. Recently, companies have started to apply Java component technology also in the area of embedded systems. Components are pieces of software with a defined interface which can be reused in different applications. Typically, components are not developed under programming restrictions for specific embedded systems, because those restrictions depend highly on the underlying hardware. Executing such software on a micro controller with very limited resources often results in unforeseen problems, e.g., in a memory overflow. Failure to detect such problems in an early stage might lead to significant costs, e.g., for replacing software on thousands of produced controllers. The authors present a semi-automatic approach to inspect Java source code in order to check for predefined hardware dependent restrictions. As an application domain we have chosen Java Smart Cards, which are very popular today, introduce their specific restrictions, and present how to inspect Java code to ensure that all restrictions are considered.