Model Development in the UML-based Specification Environment (USE)

The tool USE (UML-based Specification Environment) supports analysts, designers and developers in executing UML models and checking OCL constraints and thus enables them to employ model-driven techniques for software production. USE has been developed since 1998 at the University of Bremen. This paper will discuss to what extent and how USE relates to the questions and topics (Model quality, Modelling method, Model Effectiveness, Model Maintainability) raised for this seminar

An Example for Metamodeling Syntax and Semantics of Two Languages, their Transformation, and a Correctness Criterion

We study a metamodel for the Entity Relationship (ER) and the Relational data model. We do this by describing the syntax of the ER data model by introducing classes for ER schemata, entities, and relationships. We also describe the semantics of the ER data model by introducing classes for ER states, instances, and links. The connection between syntax and semantics is established by associations explaining that syntactical objects are interpreted by corresponding semantical objects. Analogously we do this for the Relational data model. Finally, we give a metamodel for the transformation of ER schemata into Relational database schemata. By characterizing the syntax and semantics of the languages to be transformed and also the transformation itself within the same (meta-)modeling language we are able to include equivalence criteria on the syntactical and on the semantical level for the transformation. In particular, we show that the semantical equivalence criterion requires that the ER states and the corresponding Relational states bear the same information

Towards Model Validation and Verification with SAT Techniques

After sketching how system development and the UML (Unified Modeling Language) and the OCL (Object Constraint Language) are related, validation and verification with the tool USE (UML-based Specification Environment) is demonstrated. As a more efficient alternative for verification tasks, two approaches using SAT-based techniques are put forward: First, a direct encoding of UML and OCL with Boolean variables and propositional formulas, and second, an encoding employing an intermediate, higher-level language (KODKOD, stongly connected to ALLOY). A number of further, presently not realized verification and validation tasks and the transformation of higher-level modeling concepts into simple UML/OCL models, which are checkable with SAT-based techniques, are shortly discussed. Finally, the potential of SAT-based techniques for model development is again emphasized

On Horizontal and Vertical Relationships between Models

Detecting, modeling and managing relationships between models are central tasks within model-driven engineering. By taking a simple view on software development, we distinguish in a vertical dimension between domain-specific models, core models, and executable models. A typical example for a vertical relationship is the refinement relationship beween a core model and an executable model. In the horizontal dimension, there may be several so-called property models which have the task to validate or verify particular properties of the core model. Software development coincides in our view with model development, and therefore finding the right models and their relationships is a crucial task

Teaching Model Views with UML and OCL

The specification of any non-trivial system is normally composed of a set of models. Each model describes a different view of the system, focuses on a particular set of concerns, and uses its own notation. For example, UML defines a set of diagrams for modelling the structure and behavior of any software system. One of the problems we perceived with our students is that they are able to understand each one of these diagrams, but they have problems understanding how they are related, and how the overall system specifications work when composed of a set of views. This paper presents a simple case study that we have developed and successfully used in class, which permits students developing the principal views of a system, simulate them, and check their relations.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Analyzing Semantic Properties of OCL Operations by Uncovering Interoperational Relationships

The OCL (Object Constraint Language) as part of the UML (Unified Modeling Language) is a rich language with different collection kinds (sets, multi-sets, sequences) and a large variety of operations defined thereon. Without negating the strong correlation between both fields we can say that these operations have their origin partly in logic (like the operations forAll and exists) and partly in computer science, in particular database systems (like the operation select). Some of these operations may be expressed in terms of other operations. This paper presents a systematic study of relationships which hold between OCL features like the mentioned operations. Apart from presenting the relationships between operations in a conceptual way, the relationships are described by a formal metamodel allowing systematic and computer supported access to the operation relationships by querying an underlying formal description

Generating Effective Test Suites for Model Transformations Using Classifying Terms

Generating sample models for testing a model transformation is no easy task. This paper explores the use of classifying terms and stratified sampling for developing richer test cases for model transformations. Classifying terms are used to define the equivalence classes that characterize the relevant subgroups for the test cases. From each equivalence class of object models, several representative models are chosen depending on the required sample size. We compare our results with test suites developed using random sampling, and conclude that by using an ordered and stratified approach the coverage and effectiveness of the test suite can be significantly improved.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Employing Classifying Terms for Testing Model Transformations

This contribution proposes a new technique for developing test cases for UML and OCL models. The technique is based on an approach that automatically constructs object models for class models enriched by OCL constraints. By guiding the construction process through so-called classifying terms, the built test cases in form of object models are classified into equivalence classes. A classifying term can be an arbitrary OCL term on the class model that calculates for an object model a characteristic value. From each equivalence class of object models with identical characteristic values one representative is chosen. The constructed test cases behave significantly different with regard to the selected classifying term. By building few diverse object models, properties of the UML and OCL model can be explored effectively. The technique is applied for automatically constructing relevant source model test cases for model transformations between a source and target metamodel.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech