uniform support for modeling crosscutting structure

University of British Columbia

Software Practices Lab

Uniform Support for Modeling

Crosscutting Structure

Maria TkatchenkoGregor Kiczales

Work supported by IBM and NSERC.

AOSD 2005 2

Crosscutting in a ‘UML’ Model

Advice:advise

method(Subject.change(…)):“moving concern”

AOSD 2005 3

Crosscutting in a ‘UML’ Model

AOSD 2005 4

Crosscutting in a ‘UML’ Model

Role Binding:

bind Line.moveBy, Point.moveBy, Point.setX, Point.setY

to Subject.change

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

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

AOSD 2005 7

Terminology

• Model– as in modeling, UML, MDD, meta-model…

• JPM– as in join point model– supports the above crosscutting models

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

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

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?

AOSD 2005 11

Meta-Model

FieldDecl MethodDecl AdviceDecl

ClassMemberDeclClassDecl SequenceDecl MethodCallDecl

ClassDiagramMemberDecl SequenceDiagramMemberDecl

Declaration

JoinPoint

crosscutByList: List<JoinPoint>

AOSD 2005 12

Crosscutting in the weaver

(<jp>, <jp>, <jp>, <jp>, <jp>, <jp>, …)

AOSD 2005 13

Crosscutting in the weaver

(<jp>, <jp>, <jp>, <jp>, <jp>, <jp>, …)

AOSD 2005 14

Crosscutting in the weaver

(…<jp>, …)

(… <jp>, …)

• every element has

crosscutByList

• two join points per

crosscutting interaction

AOSD 2005 15

Crosscutting in the weaver

Role Binding:

bind Line.moveBy, Point.moveBy, Point.setX, Point.setY

to Subject.change

(<jp>, <jp>, <jp>, <jp>, <jp>, <jp>, …)

• same thing happens

for all kinds of cc

AOSD 2005 16

Crosscutting in the weaverAdvice: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?

(<jp>, <jp>, <jp>, <jp>, <jp>, <jp>, …)

(<jp>, <jp>, <jp>,…)

AOSD 2005 17

Crosscutting in the weaverAdvice: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?

(<jp>, <jp>, <jp>, <jp>, <jp>, <jp>, …)

(<jp>, <jp>, <jp>,…)

( <jp>, <jp>,…)

AOSD 2005 18

Implementation• Simple staged approach to weaving

1. role binding2. inter-type declarations3. sequence diagrams4. 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

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;

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));

} }

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

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

University of British Columbia

Software Practices Lab

Uniform Support for Modeling

Crosscutting Structure

QUESTIONS?