Graph Constraint Evaluation over Partial Models by Constraint Rewriting

Abstract

Abstract. In the early stages of model driven development, models are frequently incomplete and partial. Partial models represent multiple possible concrete models, and thus, they are able to capture uncertainty and possible design decisions. When using models of a complex modeling language, several well-formedness constraints need to be continuously checked to highlight conceptual design flaws for the engineers in an early phase. While well-formedness constraints can be efficiently checked for (fully specified) concrete models, checking the same constraints over partial models is more challenging since, for instance, a currently valid constraint may be violated (or an invalid constraint may be respected) when refining a partial model into a concrete model. In this paper we propose a novel technique to evaluate well-formedness constraints on partial models in order to detect if (i) a concretization may potentially violate or (ii) any concretization will surely violate a well-formedness constraint to help engineers gradually to resolve uncertainty without violating well-formedness. For that purpose, we map the problem of constraint evaluation over partial models into a regular graph pattern matching problem over complete models by semantically equivalent rewrites of graph queries.

A graph solver for the automated generation of consistent domain-specific models

“…(1) We formulate model generation as a refinement of partial models [26,27] where initial abstract model fragments are gradually refined and concretized during exploration. (2) We provide partial model refinement rules as decision and unit propagation steps by following core SAT-solving techniques.…”

“…(2) We provide partial model refinement rules as decision and unit propagation steps by following core SAT-solving techniques. (3) We use incremental graph query evaluation of the VIATRA engine [28] to efficiently evaluate violations of constraints over partial models during model generation [27]. (4) We integrate shape analysis as state encoding [29][30][31] for graphs to efficiently detect if two partial models should be treated as equivalent during exploration.…”

Iterative Generation of Diverse Models for Testing Specifications of DSL Tools

“…An abstract state Vertex is further refined into RegularStates (like State or FinalState) and PseudoStates (like Entry, Exit or Choice). Formally [32,34], a metamodel defines a vocabulary of type and relation symbols Σ = {C 1 , . .…”

“…In many industrial modeling tools, WF constraints are captured either by OCL constraints [24] or graph patterns (GP) [41] where the latter captures structural conditions over an instance model as paths in a graph. To have a unified and precise handling of evaluating WF constraints, we use a tool-independent logic representation (which was influenced by [29,32,34]) that covers the key features of concrete graph pattern languages and a first-order fragment of OCL.…”

“…Internally, our tool operates over partial models [30,34] where instance models are derived along a refinement calculus [43]. The shapes of intermediate (partial) models found during model generation are continuously being computed.…”