metodologías de desarrollo de software (ciclo de vida) juan carlos olivares rojas msn:...
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Metodologías de Desarrollo de Software (Ciclo de Vida)
Juan Carlos Olivares Rojas
MSN: juancarlosolivares@hotmail.comjcolivar@itmorelia.edu.mx
http://antares.itmorelia.edu.mx/~jcolivar/@jcolivares
Social Network: Facebook, LinkedIn. Hi5
Agenda• Introduction
• Aspect-Oriented Programming Fundamentals
• Examples
Software Development Today
Evolución del SWSoftware Evolution
Evolución del SWSoftware Evolution
Sw Development Problems
• A complex system can visualize like as combined implementation of multiple concerns
Sw Development Problems
class Book {…..<all things about book><error handling>…}
class Partner {…..<all things about Partner><error handling><access controlling>}
class Rent {…..
<all things about Rent><error handling><access controlling>
}
class BookStore { private Book [] books ; private Partner [] partners; public BookStore() { … public void load( Partner p, Book b) { if validControlAccess() then{ // code of the method } else{ throwException(); } }
public void addPartner(Partner p){ if validContolAccess() then{ // code of the method } else{ throwException(); } }// the rest of the class methods}
Access ControlAccess Control
Sw Development Problems
Tyranny of the Dominant Decomposition
• Descomposition by Form, Color or size• We must choose only one principal model
Tyranny of the Dominant Decomposition
• Order by Form
• Order by Color
Color-Form Hierarchy• We must elect one principal model.
In this case: color and later, form
AOP Definition• AOP was created by Gregor Kickzales and
his Research Team at Palo Alto Research Center in 1996.
• “ An Aspect is a modular unit that is spreand in another functional units. The aspects exist in the design stage as in the implementación stage…”
• An Aspect is a concept that it’s difficult encapsulate clear and easily.
AOP• An aspect is the unit which encapsulate a
cross-cutting concern.
• AOP promoves the separation of concerns through mechanisms which abstract and compose this concepts troughout the system.
Traditional Structure of a Compiler
Lenguaje
Compilador o Intérprete
EJECUTABLE
PROGRAMA
Compiling Process in POA
... Lenguaje base
Lenguaje de aspectos 1
Lenguaje de aspectos N
... TEJEDOR (WEAVER)
EJECUTABLE
PROGRAMA DE ASPECTOS N
PROGRAMA DE ASPECTOS 1
PROGRAMA DE COMPONENTES
ProgramProgram
AOP Program Structure
AOP Program Structure
AOP Advantages
POA ConceptsJoinPoint It’s a well-defined position inside of
object-oriented code, for instance, the declaración of a method.
Pointcut It’s a set of conditions applied to a JoinPoint, when the conditions are true, it will active and execute an Execution Point asigned at this PointCut.
Advice It’s a Fragment of Code tha it’s executed when is actived PointCut.
Aspect It’s the combination of JoinPoint, Pointcuts and Advices.
Highlevel View of AspectJ
Java Program
AspectJ
Advice
pointcutadvice body
join point
An Aspect Definition
Aspect Control {
JoinPoint securityOperations = call s BookStore.loan & calls BookStore.addPartner& ...
Before securityOperations: {if !=(validControlAcces()) then{ throwsExcepcion(); }
}
AOP and OOP Relation
Class A
Class A1
Attb1
Attb2
Method 1
Clase A2
Attb 3
Method 1
Method 2
OOP: common concerns
AOP: crosscuting concerns
OOP Evolution to AOP
Own behavior Own behavior
Persistence
Trace
……..
Own Behavior Owbn Behavior
Persistence Trace
Class A Class B
Class A Class B
Classes
Aspects
AOP vs OOP
POA Advantages• A code less complicated, more natural
and more reduced.
• More facilities to think about the concerns, since they are separate and dependencies between them are minimal.
• An easier code to debug and to mantein.
AOP Tools
• Langauges for Programming Aspects:
• AspectJ: A Java Extension. The most popular.
• AspectC++, AspectS, CAESAR.
• .NET Languages: Weave.NET, Source Weave.
Class Bank Problem
public class Bank { // other declarations
public double processDebit(long idAccount, double amount) { // openning a transaction
try { // retrieve account // business validation // business logic associated with debit // persistencia del nuevo estado // traceo del movimiento para auditoria // cierre exitoso de la transacción (commit) return new amount account; } catch (Exception e) { // trace the audit exception // close abnormal transaction (rollback) // relauch the exception in superior layers } }
// other business process declarations}
Transaction
Persistence
Traceability
Aspectual Descomposition• Separation of concerns
• Aims to isolate cross cutting concerns
• Each one of these concerns will be implemented in a separate unit.
Aspectual Recomposition
AOP Bank Versionpublic class Bank { // other declarations
public double processDebit(long account, double amount) {
// validaciones del negocio // debit business logic return new amount account;}
// another business methods declarations}
Tran
sacc
iona
lidad
Pers
iste
ncia
Traz
abilid
ad
Logging in org.apache.tomcat
• where is logging in– red shows lines of code that handle logging – not in just one place– not even in a small number of places
logging is not modularized
Hello World with Aspectspackage mx.edu.itmorelia.aspects;public class HW {
private String message; public HW() {
this.message = “Hello World";}public void setMessge(String M){
this.menssage = M;}public String getMessage(){
return this.message;}public void showMessage(){
System.out.println(this.message);}
}
package mx.edu.itmorelia.aspects;
public class HelloWorld {public static void main(String[] args) {
HW H; H= new HW();H.showMenssage();
}}
Hello World with Aspects
package mx.edu.itmorelia.aspects;
public aspect Aspect {pointcut messagesToPrint() : call (void HW.showMessage());
before(): messagesToPrint(){ System.out.println(“Hi everybody!"); }after(): messagesToPrint(){ System.out.println(“Chao everybody!"); }
}
Hello World with Aspects
Other Implementations• import
org.aspectj.lang.annotation.Aspect;• @Aspect • public class Aspecto { ... }
• @<advice-specification>("<pointcut-kind>( [<access-specifier>] <return-type> <class-name>.<method-name>({<arg-type>}) )")public void metodo() { ... }
Other Implementations• @Pointcut("<pointcut-kind>( [<access-
specifier>] <return-type> <class-name>.<method-name>({<arg-type>}) )")public void <pointcut-name>() { ... }
• @<advice-specification>("<pointcut-name>()")
• public void metodo() { ... }
Other Implementations@Before("execution(public void
paquete.clase.metodo(String))")public void adviceEjemplo()
{ System.out.println("Antes del metodo"); }
Other Implementations@Pointcut("execution(public void
paquete.clase.metodo(String))") public void pointcutEjemplo() {}
@Before("pointcutEjemplo()") public void adviceEjemplo()
{ System.out.println("Antes del metodo"); }
Alternatives to Aspects
• Languages (OO, Componet-Based)
• Design Patterns
• Reflection
PointCut
PointCut• When a particular method is executed:
– execution(void Point.setX(int))
• When a method is invocated: call(void Point.setX(int))
• When a error handling is invocated: handler(ArrayOutOfBoundsException)
• When the object is actually executed: this(SomeType).
42
PointCut Examples
• When a method belongs to a class:– within(MyClass)
• When the JoinPoint is in the control flow of a call main method we need to use: cflow
• The target point refers to any possible JoinPoint
43
Pointcut Designator Wildcards
• It’s possible to use wildcards
• What do the next instructions do?– execution(* *(..)) – call(* set(..)) – execution(int *()) – call(* setY(long)) – call(* Point.setY(int)) – call(*.new(int, int))
PointCut
• JoinPoint Types– Methods– Constructors– Get/Set– Exception Handler
a Line
dispatch
call join points
execution join points
PointCut Examples• We can applicate the next operations: or (“||”), and
(“&&”) and not (“!”).
• Examples:– target(Point) && call(int *())– call(* *(..)) && (within(Line) || within(Point)) – within(*) && execution(*.new(int))– !this(Point) && call(int *(..))
46
Advice Type• before advice
• after advice
• after returning
• after throwing
• around advice
47
Parameterized Advice• We can acces to the context of a
JoinPoint as follow:
• pointcut setXY(FigureElement fe, int x, int y): call(void FigureElement.setXY(int, int)) && target(fe) && args(x, y);
• after(FigureElement fe, int x, int y) returning: setXY(fe, x, y) { System.out.println(fe + " moved to (" + x + ", " + y + ").");}
Another Example
HistoryUpdating
Display
*
2Point
getX()getY()setX(int)setY(int)moveBy(int, int)
Line
getP1()getP2()setP1(Point)setP2(Point)moveBy(int, int)
Figure
makePoint(..)makeLine(..)
FigureElement
moveBy(int, int)
49
Another Example
HTTPRequest
HTTPResponse
Servlet
getCookies()getRequestURI()(doc)getSession()getRequestedSessionId()...
getRequest()setContentType(contentType)getOutptutStream()setSessionId(id)...
SessionInterceptor
requestMap(request)beforeBody(req, resp)...
SessiongetAttribute(name)setAttribute(name, val)invalidate()...
References• Mejía, P. (2008), Programación Orientada
a Aspectos, CINVESTAV, México.
• Quintero, A. (2000), Visión General de la Programación Orientada a Aspectos. Languages and Information System Department. Informatic and Estadistic Faculty, Sevilla University, Spain.
• Rodriguez M., POA, Gerente Relaciones Académicas, Microsoft Cono Sur
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