Incremental Model Queries over EMF Models

Model-driven development tools built on industry standard platforms, such as the Eclipse Modeling Framework (EMF), heavily utilize model queries in various activities, including model transformation, well-formedness constraint validation and domain-specific model execution. As these queries are executed rather frequently in interactive modeling applications, they have a significant impact on the runtime performance of the tool, and also on the end user experience. However, due to their complexity, they can be time consuming to implement and optimize on a case-by-case basis. Consequently, there is a need for a model query framework that combines an easy-to-use and concise declarative query formalism with high runtime performance, so that even complex model queries can be executed instantaneously, even on large models found in industrial applications. In this paper, we propose a declarative EMF model query framework using the graph pattern formalism as the query specification language. These graph patterns describe the arrangement and properties of model elements that correspond to, e.g. a well-formedness constraint, or an application context of a model transformation rule. For improved runtime performance, we employ incremental pattern matching techniques: matches of patterns are stored and incrementally maintained upon model manipulation. As a result, query operations can be executed instantly, independently of the complexity of the constraint and the size of the model. We demonstrate our approach in an industrial (AUTOSAR) model validation context and compare it against other solutions.