Aspect-oriented software development (AOSD) seeks to modularize software systems by isolating secondary concerns from the main program's logic. AOSD allows multiple concerns to be expressed separately and then automatically unified. It focuses on identifying, specifying, and representing cross-cutting concerns as separate, modular units that can be composed into a working system. Aspects encapsulate concerns and are composed of pointcuts and advice bodies. Pointcuts define where advice code should be executed.

1. Aspect Oriented Software
Development
By:
Maryam Malekzad
M.Tech II ­ 11301

2. Birth of AOSD ;)
AOSD describes a number of approaches to software
AOSD
modularization and composition including, in order of
publication:
 reflection and metaobject protocols, Composition
Filters, developed at the University of Twente in the
Netherlands,
Netherlands
 Subject­Oriented Programming (later extended as
Multidimensional Separation of Concerns) at IBM
 Feature Oriented Programming at University of Texas
at Austin
AOSD Maryam Malekzad M.Tech. ­ 11301 PUCSD 2

3. Birth of AOSD ­ continue ­
 Adaptive Programming at Northeastern University,
USA
 and Aspect­Oriented Programming (AOP) at Palo
Alto Research Center.
 The term aspect­oriented was introduced by
Gregor Kiczales and his team at Palo Alto
Gregor Kiczales
Research Center
AOSD Maryam Malekzad M.Tech. ­ 11301 PUCSD 3

4. What is the main Idea?
Aspect­oriented software development (AOSD):
 is an emerging software development technology that
seeks
 new modularizations of software systems
 in order to isolate secondary or
 supporting functions from the main program's business
logic.
 AOSD allows multiple concerns to be expressed
 separately
 and automatically unified into working systems.
AOSD Maryam Malekzad M.Tech. ­ 11301 PUCSD 4

5. AOSD's target?
Aspect­Oriented Software Development focuses on
Aspect­Oriented Software Development
 the identification,
 specification and
 representation of cross­cutting concerns and
 their modularization into separate functional
units
 as well as their automated composition into a
working system.
AOSD Maryam Malekzad M.Tech. ­ 11301 PUCSD 5

6. AOSD's target? ­ continue ­
 The focus of Aspect­Oriented Software
Development (AOSD) is in the investigation
and implementation of new structures for
software modularity that provide support
software modularity
for explicit abstractions to modularize
concerns.
AOSD Maryam Malekzad M.Tech. ­ 11301 PUCSD 6

7. What is ”Aspect” ? (1)
 An aspect is a module that encapsulates a concern.
 An aspect is composed of pointcuts, advice bodies
and inter­type declarations.
 In some approaches, and aspect may also contain
classes and methods.
 Inter­type declarations allow the programmer to
modify a program's static structure, such as class
members and classes hierarchy. New members
can be inserted and classes can be pushed down
the class hierarchy.
AOSD Maryam Malekzad M.Tech. ­ 11301 PUCSD 7

8. What is ”Aspect” ? (2)
 An aspect is a common feature that's typically
scattered across methods, classes, object
hierarchies, or even entire object models. It is
behavior that looks and smells like it should have
structure, but you can't find a way to express this
structure in code with traditional object­oriented
techniques.
AOSD Maryam Malekzad M.Tech. ­ 11301 PUCSD 8

9. What is ”Pointcut” ?
In aspect­oriented computer programming:
 a pointcut is a set of join points.
­ Whenever the program execution reaches one of the join
points described in the pointcut, a piece of code
associated with the pointcut (called advice) is executed.
­ This allows a programmer to describe where and when
additional code should be executed in addition to an
already defined behavior.
AOSD Maryam Malekzad M.Tech. ­ 11301 PUCSD 9

10. What is ”Pointcut” ? ­continue ­
 Pointcut permits the addition of aspects to existing
Pointcut
software, or the design of software with a clear
separation of concerns, wherein the programmer
weaves (merges) different aspects into a complete
application.
AOSD Maryam Malekzad M.Tech. ­ 11301 PUCSD 10

11. AOP ?!
Aspect­oriented programming (AOP) is a
Aspect­oriented programming (AOP)
programming paradigm that aims to:
 increase modularity
 by allowing the separation of cross­cutting
concerns.
 AOP forms a basis for aspect­oriented software
development.
AOSD Maryam Malekzad M.Tech. ­ 11301 PUCSD 11

12. Cross­cutting Concerns Vs. Core Concern
cross­cutting concerns are :
cross­cutting concerns
 aspects of a program that affect other concerns.
 These concerns often
 cannot be cleanly decomposed from the rest of the
system in both
 the design
 and implementation, and
 can result in either
 scattering (code duplication),
 tangling (significant dependencies between systems),
 or both.
AOSD Maryam Malekzad M.Tech. ­ 11301 PUCSD 12

13. Do you know ?
 The implementation of a concern is scattered if its
scattered
code is spread out over multiple modules. The
concern affects the implementation of multiple
modules. Its implementation is not modular.
 The implementation of a concern is tangled if its
tangled
code is intermixed with code that implements
other concerns. The module in which tangling
occurs is not cohesive.
 Scattering and tangling often go together, even
though they are different concepts.
AOSD Maryam Malekzad M.Tech. ­ 11301 PUCSD 13

14. What is ”Concern” ?
a concern :
concern
 is a particular set of information that has an effect
on the code of a computer program.
 It can be as general as the details of database
interaction or
 as specific as performing a primitive calculation,
 depending on the level of conversation between
developers and the program being discussed.
AOSD Maryam Malekzad M.Tech. ­ 11301 PUCSD 14

15. AO Requirement Engineering
"Early Aspects" focuses on the
"Early Aspects"
 identification, specification and representation of
crosscutting properties at the requirement level.
 Examples of such properties include:
 security, mobility, availability and real­time
constraints.
 Crosscutting properties are:
 requirements, use cases or features that have a
broadly scoped effect on other requirements or
architecture components.
AOSD Maryam Malekzad M.Tech. ­ 11301 PUCSD 15

16. AO System Architecture
 focuses on the localization and specification of
crosscutting concerns in architectural designs.
 Crosscutting concerns that appear at the
architectural level cannot be modularized by
redefining the software architecture using
conventional architectural abstractions.
 Aspect­oriented system architecture languages
propose explicit mechanisms to identify, specify
and evaluate aspects at the architecture design
level.
AOSD Maryam Malekzad M.Tech. ­ 11301 PUCSD 16

17. AO System Architecture
 Aspect­oriented architecture starts from the
observation that we need to identify, specify and
evaluate aspects explicitly at the architecture
design level.
 Aspectual architecture approaches describe steps
for identifying architectural aspects.
AOSD Maryam Malekzad M.Tech. ­ 11301 PUCSD 17

18. Specific Areas of Excellence are:
 the aspect­oriented architecture process itself,
 the aspect­oriented architecture notations,
 aspect­oriented architecture tool support,
 adoption and integration of aspect­oriented
architecture, and
 assessment/evaluation of aspect­oriented
architecture.
AOSD Maryam Malekzad M.Tech. ­ 11301 PUCSD 18

19. Modeling and Design
 It has the same objectives as any software design
activity, i.e. characterising and specifying the
behavior and structure of the software system.
 Its unique contribution to software design lies in the
fact that concerns that are necessarily scattered
and tangled in more traditional approaches can be
modularized.
 Typically, such an approach includes both a process
and a language.
AOSD Maryam Malekzad M.Tech. ­ 11301 PUCSD 19

20. Aspect­oriented languages
 AspectC++
 AspectJ
 AspectLua (a Lua extension)
 CaesarJ
 Compose*
 ObjectTeams
 e (verification language)
AOSD Maryam Malekzad M.Tech. ­ 11301 PUCSD 20

21. ?
AOSD Maryam Malekzad M.Tech. ­ 11301 PUCSD 21

22. Thank you
for
your attention
AOSD Maryam Malekzad M.Tech. ­ 11301 PUCSD 22