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We present a framework for modeling visual notations and for generating the corresponding visual programming environments. The framework can be used for modeling the diagrammatic notations of software development methodologies, and to generate visual programming environments with CASE tools functionalities. This is accomplished through an underlying modeling process based on the visual notation syntactic model of eXtended Positional Grammars (XPG, for short), and the associated parsing methodology, XpLR. In particular, the process requires the modeling of the basic elements (visual symbols) of a visual notation, their syntactic properties, the relations between them, the syntactic rules to formally define the set of feasible visual sentences, and a set of semantic routines performing additional checks and translation tasks. Such a process is completely supported by the VLDesk system, which enables the automatic generation of an editor for drawing visual sentences, as well as a processor for their recognition, parsing, and translation into other notations.The proposed framework also provides the basis for the definition of a meta-CASE technology. In fact, we can customize the generated visual programming environment in terms of the supported visual notation, its syntactic properties, and the translation rules. We have used this framework to model several diagrammatic notations used in software development methodologies, including those of the Unified Modeling Language.

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Sketch-based user interfaces are increasingly common and are being built for a variety of different disciplines. However, at present the implementation of sketch recognizers is quite time consuming since they are mostly based on specific techniques, as opposed to several other fields such as textual/visual languages and speech recognition, which benefit from the availability of compiler generation techniques and tools. This paper proposes a grammar formalism, namely Sketch Grammars (SkGs), for describing both the shape of the symbols' language and the syntax of sketch languages. Recognizers are automatically generated from the sketch grammar descriptions.

Recovering design pattern instances in a software system can help maintainers to understand its design and implementation. In this paper we present a fully automated design pattern recovery approach that analyzes the behavior of pattern instances both statically and dynamically. In particular, the proposed approach exploits model checking to statically verify the behavioral aspects of design pattern instances. To this end, we encode the properties defining the correct behavior of a pattern as LTL (Linear Temporal Logic) formulae and the sequence diagram representing the possible interaction traces among the objects involved in the candidate instances as PROMELA specifications. To verify whether the LTL properties are satisfied by the candidates we employ the SPIN model checking tool. The dynamic analysis of the pattern behavior is performed through a code instrumentation and monitoring phase applied on the candidate pattern instances. This phase allows us to obtain actual dynamic data during program execution, which is then used to verify its compliance to the pattern definition. The effectiveness of the proposed approach is shown by presenting and discussing the results obtained on JHotDraw and JRefactory.