Introduction

Better Faster Cheaper(pick any two)

• On-going issue that continues to motivate research in software engineering

• Applications:– continue to increase in size and complexity– need to be deployed quickly– maintenance can be ~40% of the development cost– …

• Re-use approaches proposed as solutions

Software Engineering Discipline

• Current Issues?– “tyranny of decomposition” problem– Improve re-use of components– Support “mass customization” of software– Architectures for Dynamic Adaptable Systems– …

• Active research area– Upcoming Architecture Events page maintained by the

SEI currently lists 14 conference workshop events/special issues

– http://www.sei.cmu.edu/architecture/events.html

• Different paradigms share common themes– Definition of re-usable “chunks”

• Agents in agent-oriented development• Aspects in aspect-oriented development• Services in service-oriented development• Core assets in product line development• …

– Communication among the “chunks”– Composition of the “chunks”– Use of repositories to organize/store the “chunks”

– Visual modeling for improved communication • Note. There are UML extensions available for a wide variety of

recent paradigms– UML for aspects– UML for services– UML for agents– …

– Tool support• Research/experimental tools vary widely in maturity

(documentation, robustness, completeness)

Some things to look for…(or look out for)

A posting to consider…

…in time we will construct reusable components and many architectures and someone will ask for such a system, performance, money then integrators will decide on the components and the hardware – see u bye

Up to that time we will read, research and invent "x-orienteds" every day..... x may be : object, aspect, service …

maybe i should write a methodology Tolga-oriented software development :)

Tolga Erdoðan

Adapted from posting on Requirements-Engineering@yahoogroups.com March 16/08

Aspect-oriented Paradigm: Issues

• Introductions to the aspect-oriented paradigm are at:

http://www.info.ucl.ac.be/~jbrichau/courses/introductionToAOSD.pdf

http://www.slideshare.net/jignesh/aspect-oriented-software-development

• Traditional modularization mechanisms suffer from a limitation called the tyranny of the dominant decomposition– the system can be modularized in only one way at a time– concerns that do not align with that modularization end up

scattered across many modules and tangled with one another• -> Higher coupling, lower cohesion

Aspect-oriented Paradigm: Issues

• Aspects have been proposed as a solution to the problem

– New entity to encapsulate a (crosscutting) concern

– Aspects have:• Pointcuts - provide the definitions of where and how an

aspect will cut into the design. • Advice - provide functionality when the aspect is invoked.

Aspect-oriented Paradigm

• Started at the programming language level– Aspect-oriented programming (AOP)– AspectJ, HyperJ, AspectC++, …

• Aspect-oriented modelling (AOM) followed– Architecture, Design, and Requirements– UML has been used/extended by a number of researchers

for our needs (architecture, design)• Some people argue that extensions are not needed; others argue

they are needed• Of the UML extension mechanisms used, stereotype extensions are

the most straightforward <<some aspect>>

Aspect-oriented Paradigm

• This is an active community – Annual conference and journal

• International Conference on Aspect-Oriented Software Development AOSD (http://www.aosd.net/2011/)

• Transactions on AOSD

• Comprehensive surveys are available:For example http://www.aosd-europe.net/deliverables/d11.pdf

This survey report is cited by many; however note the date (2005).

Aspect-Oriented DesignObject-Oriented Design

Problem Statements

Aspects added one at a time

Security Adaptability

Advantages: Tangling aspects handled separately, Dramatically reduce the complexity of understanding, change, and analysis,

promoting reusability

…

Module 1

Problem Statements

Module 1

weaver

Final Design

Problem: lower cohesion, higher coupling, maybe significant re-work when facing changes

Final Design

Security

Performance

Adaptability

Aspect-oriented Paradigm: Issues

Aspect-oriented Paradigm: Architecture/Design

• What would an aspect-oriented architecture/design look like?

• It depends…• Let’s take a look at a couple of examples

1. UML-AOF

http://www.aspect-modeling.org/aosd09/papers/aom1s-uetanabara.pdf

2. UML Formal design analysis framework

3. ADL?

D N S Clie n t

+ S e n d Q u e s t io n () : v o id+ A n s w e rA rriv e d () : v o id- P ro c e s s A n s w e r() : v o id

M e s s e n g e r

+ Clie n tQ u e s t io n A rriv e d (.) : v o id+ S e rv e rA n s w e rA rriv e d () : v o id+ S e n d Clie n tA n s w e r() : v o id+ S e n d S e rv e rQ u e s t io n () :v o id+ F o rw a rd Q u e s t io n () : v o id+ F o rw a rd A n s w e r() : v o id+ Clie n tQ u e s t io n A n s w e re d () : v o id+ S e rv e rQ u e s t io n Ge n e ra te d () :v o id

D a ta Re fre s h e r

+Re fre s h A n s w e rA rriv e d () : v o id-Re fre s h D a ta () : v o id

Q u e ry P ro c e s s o r

+Q u e s t io n P e n d in g () :v o id-D e c o d e M e s s a g e (): v o id

-En c o d e M e s s a g e () : v o id+P a s s A n s w e r() : v o id

D a ta b a s e

Re q u e s tGe n e ra to r

+Re fre s h M o n ito rO ff():v o id+Ge n e ra te Re q u e s t (): v o id

Re fre s h M o n ito r

-Re a d y ():v o id+T ime rO ff(): v o id

re fre s h me s s a g e

q u e ry

s e a rc h e s

re fre s h e s

mo n ito rs

t ime r o ff

C lie n t

S e rv e r

-In it ia lize ():v o id

-S e a rc h A n s w e r():v o id

S tatic M o d e l

Ge n e ra te K e y ()D is t rib u te K e y ()

En c ry p tD a ta ()

D O A A s p e c t

D O A A s p e c tD e c ry p tD a ta ()

D N S Clie n t

+ S e n d Q u e s t io n () : v o id+ A n s w e rA rriv e d () : v o id

M e s s e n g e r

+ Clie n tQ u e s t io n A rriv e d (.) : v o id+ S e rv e rA n s w e rA rriv e d () : v o id+ S e n d Clie n tA n s w e r() : v o id+ S e n d S e rv e rQ u e s t io n () :v o id+ F o rw a rd Q u e s t io n () : v o id+ F o rw a rd A n s w e r() : v o id+ Clie n tQ u e s t io n A n s w e re d () : v o id+ S e rv e rQ u e s t io n Ge n e ra te d () :v o id

D a ta Re fre s h e r

+ Re fre s h A n s w e rA rriv e d () : v o id-Re fre s h D a ta () : v o id

Q u e ry P ro c e s s o r

+ Q u e s t io n P e n d in g () :v o id-D e c o d e M e s s a g e (): v o id

-En c o d e M e s s a g e () : v o id+ P a s s A n s w e r() : v o id

D a ta b a s e

Re q u e s tGe n e ra to r

+ Re fre s h M o n ito rO ff():v o id+ Ge n e ra te Re q u e s t (): v o id

Re fre s h M o n ito r

-Re a d y ():v o id+ T ime rO ff(): v o id

re fre s h me s s a g e

q u e ry

s e a rc h e s

re fre s h e s

mo n ito rs

t ime r o ff

C lie n t

S e rv e r

-In it ia lize ():v o id

-S e a rc h A n s w e r():v o id

< < a f te r> >

Re t rie v e S IG()D O A As p ec t

< < a f te r> >

< < a f te r> >

- P ro c e s s A n s w e r() : v o id

e xe c u t io n

e xe c u t io n

e xe c u t io n

Stat i c M o de l

FDAF Step One:

Extend DNS architecture design with data origin authentication aspect

Aspect-oriented Paradigm: FDAF

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S e n d Q u e s t io n A n s w e rA rriv e d

Clie n tQ u e s t io n A n s w e re d

S e rv e rQ u e s t io n Ge n e ra te d

S e rv e rA n s w e rA rriv e d

Clie n tQ u e s t io n A rriv e d F o rw a rd Q u e s t io n

F o rw a rd A n s w e r

S e n d Clie n tA n s w e r

S e n d S e rv e rQ u e s t io n

Q u e s t io n P e n d in g D e c o d e M e s s a g e

S e a rc h A n s w e r En c o d e M e s s a g e

P a s s A n s w e r

Re fre s h M o n ito rO ff Ge n e ra te Re q u e s t

Re a d y T ime rO ff

Re fre s h A n s w e rA rriv e d Re fre s h D a ta

I n it ia lize

P ro c e s s A n s w e r

D ynam i c M o de l

FDAF Step One: Extend DNS architecture design with data origin authentication aspect (cont.)

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S e n d Q u e s t io n A n s w e rA rriv e d

Clie n tQ u e s t io n A n s w e re d

S e rv e rQ u e s t io n Ge n e ra te d

S e rv e rA n s w e rA rriv e d

Clie n tQ u e s t io n A rriv e d F o rw a rd Q u e s t io n

F o rw a rd A n s w e r

S e n d Clie n tA n s w e r

S e n d S e rv e rQ u e s t io n

Q u e s t io n P e n d in g D e c o d e M e s s a g e

S e a rc h A n s w e r

En c o d e M e s s a g e

P a s s A n s w e r

Re fre s h M o n ito rO ff Ge n e ra te Re q u e s t

Re a d y T ime rO ff

Re fre s h A n s w e rA rriv e d Re fre s h D a ta

I n it ia lize

P ro c e s s A n s w e r

Re t rie v e S IG

Ge n e ra te K e y D is t rib u te K e y En c ry p tD a ta

Q u e s t io n A n s w e r

Q u e s t io n

Q u e s t io n

Q u e s t io n

A n s w e r

A n s w e r

D e c ry p tD a ta

D ynam i c M o de l

Aspect-oriented Paradigm: FDAF

Project Management?

• Maintainability of the software is key focus for the aspect-oriented research community

• Question: How does adopting this paradigm this impact the PM?