Felix Klar

15 Years of Triple Graph Grammars

Triple graph grammars (TGGs) have been invented 15 years ago as a formalism for the declarative specification of bidirectional graph-to-graph translations. In this paper we present a list of still open problems concerning the interpretation and the expressiveness of TGGs. We will comment on extensions proposed to improve the original approach and the drawbacks that arise thereof. Consequently a more precise formalization of compulsory properties of the translation of triple graph grammars into forward and backward graph translation functions is given. Regarding these properties an interpretation and implementation of negative application conditions is derived that does not destroy the benefits of the original approach. Additionally a new demand-driven forward/backward translation rule application strategy is proposed. It guarantees for the first time automatically a correct ordering of rule applications without imposing any additional requirements on the structure of the regarded graphs.

Metamodel-based tool integration with moflon

Nowadays, a typical software development process involves many developers which participate in the development process by using a wide variety of development tools. As a consequence, the data representing the project as a whole is distributed over different development tools. For the purpose of consistency, maintainability, and traceability it is an essential task to be aware of the relationships between semantic equivalent data in different tool repositories. The real-time systems Lab at the Technische Universitat Darmstadt performs research in the area of tool and metamodel integration to provide solutions to overcome this gap. In this demonstration we present the metamodeling framework MOFLON that addresses these issues by bringing together the latest OMG standards with graph transformations and triple graph grammars. Using MOFLON, developers can generate code for specific tools needed to perform analysis and transformation on one development tool or to incrementally integrate data of different modeling tools.

Model transformation in the large

Current rule-based model transformation approaches as the Query / View / Transformation (QVT) standard or Triple Graph Grammars (TGGs) disregard means for structuring model transformation specifications. As a result large scale model transformation specifications are hard to understand and to maintain. Furthermore, these specifications cannot utilize reusing mechanisms which would reduce the size of the specifications and improve their readability. In this paper we discuss how to transfer means for structuring huge metamodels and models as provided by common modeling languages to the world of model transformation languages. We focus on generalization issues as well as on package dependencies. As a result we come up with an extension to our TGG approach that enables the user to specify structured bidirectional model transformations in a declarative way.

Extended triple graph grammars with efficient and compatible graph translators

Model-based software development processes often force their users to translate instances of one modeling language into related instances of another modeling language and vice-versa. The underlying data structure of such languages usually are some sort of graphs. Triple graph grammars (TGGs) are a formally founded language for describing correspondence relationships between two graph languages in a declarative way. Bidirectional graph language translators can be derived from a TGG, which maps pairs of related graph instances onto each other. These translators must fulfill certain compatibility properties with respect to the correspondence relationships established by their TGG. These properties are guaranteed for the original TGG approach as published 15 years ago. However, its expressiveness is pushed to the limit in most real world scenarios. Furthermore, the original approach relies on a parsing algorithm with exponential runtime complexity. In this contribution, we study a more expressive class of TGGs with negative application conditions and show for the first time that derived translators with a polynomial runtime complexity still preserve the above mentioned compatibility properties. For this purpose, we introduce a new characterization of wellformed TGGs together with a new translation rule scheduling algorithm that considers dangling edges of input graphs.

Development of tool extensions with MOFLON

The increasing complexity of embedded systems is accompanied by an increasing number and complexity of models, modeling languages and tools in the development process. This results in a need for appropriate tool support at the metamodel level. Besides the necessity to develop new languages and tools, there is also a large demand for extensions to existing tools as well as for integration frameworks. Such frameworks ensure consistency between data that is distributed over several tools. In this chapter, we present MOFLON, a metamodeling tool primarily focused on tool extension and integration. It adopts several standards such as MOF 2.0 and JMI. It also supports story driven modeling as a means of describing on-model transformations as well as a combination of MOF QVT and triple graph grammars for model-to-model transformations and integration. We present a typical application of these features to tools used in the development of embedded systems.

Generic and reflective graph transformations for checking and enforcement of modeling guidelines

In the automotive industry, the model driven development of software, today considered as the standard paradigm, is generally based on the use of the tool MATLAB Simulink/Stateflow. To increase the quality, the reliability, and the efficiency of the models and the generated code, checking and elimination of detected guideline violations defined in huge catalogues has become an essential task in the development process. It represents such a tremendous amount of boring work that it must necessarily be automated. In the past we have shown that graph transformation tools like Fujaba/MOFLON allow for the specification of single modeling guidelines on a very high level of abstraction and that guideline checking tools can be generated from these specifications easily. Unfortunately, graph transformation languages do not offer appropriate concepts for reuse of specification fragments - a MUST, when we deal with hundreds of guidelines. As a consequence we present an extension of MOFLON that supports the definition of generic rewrite rules and combines them with the reflective programming mechanisms of Java and the model repository interface standard JMI.

A Meta-model-Driven Tool Integration Development Process

The integration of languages and tools that are used for model-driven IT system development purposes is a hot research topic. Quite a number of model transformation and weaving approaches have been published rather recently that simplify the implementation of the needed integration components. Surprisingly, we are not aware of any publications that present comprehensive engineering processes for the systematic analysis, design, validation, and verification of the needed model coupling and translation services. This paper is a first contribution for the development of a standard modeling tool integration process with a main focus on the early scenario-driven requirements elicitation phases.