developing adaptive j2me applications using aspectj ayla débora and paulo borba {add,...

Developing Adaptive J2ME Applications Using AspectJ

Ayla Débora and Paulo Borba

{add, phmb}@cin.ufpe.br

Centro de Informática - UFPE

Centro de Informática - UFPE 2

Summary Introduction and Motivation

Goals The Application AspectJ

Adaptive Concerns Customization Screens Caching Internationalization

Conclusions


Introduction and Motivation

Goals: Evaluate AspectJ as a way to provide adaptive

behaviors for J2ME applications Identify advantages and drawbacks of using

AspectJ for this purpose Develop several adaptive concerns in an existent

J2ME application and identify possible patterns Compare AspectJ solutions to pure Java solutions

using Design Patterns


Introduction Adaptability

Adaptable x Adaptive Adaptability x Ubiquity Why J2ME?

The Application J2ME Dictionary Possible adaptive behaviors


The Dictionary Application


AspectJ Language

public aspect Screens { }

pointcut showingScreen(): execution (public void showScreen(byte)) ;

before(): showingScreen(){ System.out.println("A screen will be shown");

}

public static final byte A.REGISTRATION_SCREEN=-3;

Pointcut

Advice

Introduction


Adaptive Concerns

Customization Screens Caching Internationalization


Customization Concern

Configuring the adaptation

Comparing with design patterns

Reusability Comparing with a pure

Java implementation


Customization Concern

pointcut MIDletStart(MIDlet midlet):execution(void startApp())&&target(midlet);

before(MIDlet midlet): MIDletStart(midlet){ adaptBefore(midlet);}void around (MIDlet midlet) : MIDletStart(midlet){ boolean shouldProceed = adaptAround(midlet); if (shouldProceed) proceed(midlet);}after(MIDlet midlet): MIDletStart(midlet){ adaptAfter(midlet);}


Screen Concern Using Introduction Changing screens

DictionaryConstants

getStringValue()addStringValue()

GeneralList MainMenuEnhancerRegistrationScreen

DictionaryController

getInstance()initializeScreens()addScreen()getScreen()showScreen()

PresentationScreen

paint()commandAction()

UpdateObject

Screens<<aspect>>


Caching Concern

Avoids server connections Transparency

Caching

writeServerContentsOnXML()

<<aspect>>

ServerUpdate

DictionaryCustomization

getUpdateObject()

<<aspect>>

UpdateObjectConfig

makeUpdateObject()

<<aspect>>

UpdateObject

getInputSearchData()getSearchMechanism()getDictionaryEntries()changeMainMenu()

Screens<<aspect>>


Internationalization Concern The need for refactoring The use of auxiliary classes Interference between aspects

Internationalization

setLanguage()getLanguage()addStringValue()getStringValue()

InternationalizationAspect

internationalization

DictionaryConstants

getStringValue()addStringValue()


Internationalization Concernpointcut internationalizing(Object key): execution(public static String DictionaryConstants.getStringValue(Object))&&args(key);

String around(Object key): internationalizing(key){ return internationalization.getStringValue(key);}

pointcut internationalizingNewScreens (Internationalization in): initialization(public Internationalization.new())

&& target(in);


Conclusions

AspectJ and the implementation of adaptive concerns

Pure OO solutions generally require more changes

The use of J2ME and the identification of join points

The use of auxiliary classes The necessity of refactoring


Conclusions

Interference between aspects Reusing aspects Dynamic adaptations Problems in J2ME while using AspectJ Applicability for other platforms

Developing Adaptive J2ME Applications Using AspectJ

Ayla Débora and Paulo Borba

{add, phmb}@cin.ufpe.br

Centro de Informática - UFPE

developing adaptive j2me applications using aspectj ayla débora and paulo borba {add,...

Documents