1. University of British Columbia Software Practices Lab Uniform Support for Modeling Crosscutting Structure Maria Tkatchenko Gregor Kiczales Work supported by IBM and NSERC.

2. AOSD 2005 2 Crosscutting in a ‘UML’ Model Advice: advise method(Subject.change(…)): “moving concern”

3. AOSD 2005 3 Crosscutting in a ‘UML’ Model

4. AOSD 2005 4 Crosscutting in a ‘UML’ Model Role Binding: bind Line.moveBy, Point.moveBy, Point.setX, Point.setY to Subject.change

5. AOSD 2005 5 Crosscutting in a ‘UML’ Model Advice: advise method(Subject.change(…)): “moving concern” Role Binding: bind Line.moveBy, Point.moveBy, Point.setX, Point.setY to Subject.change

6. AOSD 2005 6 Related Work [Katara, Mikkonen, ‘02] –hierarchy of related refinements –merge sequences for composed behaviour [Lions et.al.,’02] –AOP in UML through use of meta-modeling in OpenTool/UML [Baniassad, Clarke, ‘04] –modeler identifies and binds aspects (themes) –throughout lifecycle of project [Kande et.al.,’02] –first-class aspects in UML

7. AOSD 2005 7 Terminology Model –as in modeling, UML, MDD, meta-model… JPM –as in join point model –supports the above crosscutting models

8. AOSD 2005 8 Goals Foundation for modeling crosscutting structure –Compositional different model elements different crosscutting perspectives –Simple uniform linear in number of crosscutting views (not exponential) relatively easy to add new kind of crosscutting Simplifies implementation of modeling tool –directly benefits for modeling tool implementer, meta- modeler i.e. would it be easier to add pattern support with this approach? –indirectly benefits modeler

9. AOSD 2005 9 What JPM (Join Point Model) Supports That JPMs are fundamental mechanism for support of crosscutting A simple JPM for UML –(for now, taking freedom to change the UML meta-model) JPMs have three parts [Masuhara, ‘03] Join points Identifying join points Semantic effect

10. AOSD 2005 10 JPM Join points –model elements –Class, Method, Field, Advice in Class Diagram –Method Call, Sequence (focus of control) in Sequence Diagram –uniform, but 2 JPs per crosscutting interaction Identifying join points –signatures, type patterns, pointcuts… Semantic effect –each has particular declaration semantics declare a class, method, sequence, advice… Weaver –based on Eclipse EMF framework –collects crosscutting among the elements –what elements crosscut each other?

11. AOSD 2005 11 Meta-Model FieldDeclMethodDeclAdviceDecl ClassMemberDeclClassDeclSequenceDeclMethodCallDeclClassDiagramMemberDeclSequenceDiagramMemberDecl Declaration JoinPoint crosscutByList: List

12. AOSD 2005 12 Crosscutting in the weaver (,,,,,, …)

13. AOSD 2005 13 Crosscutting in the weaver (,,,,,, …)

14. AOSD 2005 14 Crosscutting in the weaver (…, …) every element has crosscutByList two join points per crosscutting interaction

15. AOSD 2005 15 Crosscutting in the weaver Role Binding: bind Line.moveBy, Point.moveBy, Point.setX, Point.setY to Subject.change (,,,,,, …) same thing happens for all kinds of cc

16. AOSD 2005 16 Crosscutting in the weaver Advice: advise method(Subject.change(…)): “moving concern” Role Binding: bind Line.moveBy, Point.moveBy, Point.setX, Point.setY to Subject.change how is advice affected by role binding? (,,,,,, …) (,,,…)

17. AOSD 2005 17 Crosscutting in the weaver Advice: advise method(Subject.change(…)): “moving concern” Role Binding: bind Line.moveBy, Point.moveBy, Point.setX, Point.setY to Subject.change how is advice affected by role binding? (,,,,,, …) (,,,…) (,,…)

18. AOSD 2005 18 Implementation Simple staged approach to weaving 1.role binding 2.inter-type declarations 3.sequence diagrams 4.advice Simplifies semantic interactions –advice depends on roles, but not vice versa Each pass records –relevant semantic information type and method inheritance tables –additions to crosscutByList of each JP

19. AOSD 2005 19 Use of woven information Question: how to find out whether an element has advice applied to it? boolean hasAdvice(Decl decl) { for (Decl otherDecl: decl.getCrosscutByList()) if (otherDecl instanceof AdviceDecl) return true; return false;

20. AOSD 2005 20 Use of woven information Question: how to build the complete (possible) cflow of a call C for C and any calls in its sequence diagram, repeat containedCalls(call) List containedCalls(Call c1) { List result; for (Decl c2: c1.getCrosscutByList()) if (c2 instanceof Call && c1.getSignature().matches(c2.getSignature()) { result.add(c2); result.addAll(containedCalls(c2)); }

21. AOSD 2005 21 Status of work Done so far –JPM design –UML meta-model –UML language –Implementation: weaver Prototype Modular –Simplified: reasonable subset of UML no methodReceipt, methodReturn join points in Sequence Diagrams no other diagrams

22. AOSD 2005 22 Summary Simple approach to modeling crosscutting –for existing and new kinds of crosscutting Simple and modular implementation Approach consists of –JPM –extension to the UML meta-model –weaver

23. University of British Columbia Software Practices Lab Uniform Support for Modeling Crosscutting Structure QUESTIONS?