public Tuples resolve(QueryEvaluationContext context, ModelExpression modelExpr, ConstraintExpression constraintExpr) throws Exception { ConstraintIn constraint = (ConstraintIn)constraintExpr; ModelExpression graph; if (constraint.getGraph() instanceof URIReferenceImpl) { graph = new ModelResource(((URIReferenceImpl)constraint.getGraph())); } else { assert constraint.getGraph() instanceof Variable; graph = new ModelVariable((Variable)constraint.getGraph()); } return ConstraintOperations.resolveConstraintExpression(context, graph, constraint.getConstraintParam()); } }),