Backwards reasoning for model transformations: Method and applications

Model transformations are key elements of Model Driven Engineering. Cur-rent challenges for transformation languages include improving usability (i.e.,succinct means to express the transformation intent) and devising powerfulanalysis methods.In this paper, we show how backwards reasoning helps in both respects.The reasoning is based on a method that, given an OCL expression and atransformation rule, calculates a constraint that is satisfiable before the ruleapplication if and only if the original OCL expression is satisfiable afterwards.With this method we can improve the usability of the rule executionprocess by automatically deriving suitable application conditions for a rule(or rule sequence) to guarantee that applying that rule does not break anyintegrity constraint (e.g. meta-model constraints). When combined withmodel finders, this method facilitates the validation, verification, testing anddiagnosis of transformations, and we show several applications for both in-place and exogenous transformations.