pointcut -based architectural interface for bridging a gap between design and implementation

POSL (Principles of Software Languages) Gr.Kyushu Institute of Technology, Japan

http://posl.minnie.ai.kyutech.ac.jp/

Pointcut-based Architectural Interfacefor

Bridging a Gap between Design and Implementation

Naoyasu Ubayashi, Hidenori Akatoki, Jun Nomura

July 7, 2009

ECOOP Workshop RAM-SE’09

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Overview Architectural design

plays an important role in the software development.– Robustness– Reliability– Maintainability

However, it is not easy to– implement the result of

architecture modeling as a program preserving the architectural correctness;

– maintain the traceability between an architecture and program code; and

– deal with software evolution.

public class Subject{ 　　 private Vector observers = new Vector(); private String state = “”; 　　　　 public void addObserver(Observer o){ … } 　　 public void removeObserver(Observer o){ … } 　　 public void notify(){ 　　　　 Iterator i = observers.iterator(); 　　　　while(i.hasNext() ){ 　　　　　　 Observers o = (Observer)i.next(); 　　　　　　 o.update( this ); 　　　　 } 　　 } public void setState(String s){ state = s; } public String getState() {return state; }}

Progr

am C

ode

Bidirectional Traceability !

Archite

cture

Bug

Archface

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Outline Motivation Archface Archface for Java Discussion Conclusion

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1. MOTIVATION1. Motivation

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Motivating example

public class Subject { private String state = ""; public String getState() { return state; } public void setState(String s) { state = s; } … }

Architectural Design(Observer Pattern)

Code

Bug

Architectural constraints(Collaborative behavior)are not preserved !

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Solution ?

MDD + Code generation ? Fine, but …

Architectural design should be abstract !

Detaile

d

Mod

el

Descr

iption

s ProgramCode

Full codegeneration

Detailed modelgeneration

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Problems to be tackledIn current MDD, it is not easy to

create an architectural model with adequate abstraction level

implement the result of architecture modeling as a program preserving the architectural correctness

recover architecture from program code

maintain the traceability between architecture and program code

deal with software evolution.

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2. Archface

(= Architecture + Interface)

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public class Subject{ 　　 private Vector observers = new Vector(); private String state = “”; 　　　　 public void addObserver(Observer o){ … } 　　 public void removeObserver(Observer o){ … } 　　 public void notify(){ 　　　　 Iterator i = observers.iterator(); 　　　　while(i.hasNext() ){ 　　　　　　 Observers o = (Observer)i.next(); 　　　　　　 o.update( this ); 　　　　 } 　　 } public void setState(String s){ state = s; } public String getState() {return state; }}

Our Approach

Archite

cture

Progr

am C

ode

Archface: architectural interface for bridging a gap between design modeling and implementationArchitectural information

is encapsulated in interfaces

Archface

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Architecture Descriptions Supported by Archface

Component-and-Connector Architecture (Structure)

Collaborations among Components (Behavior)

<Example: Observer Pattern>

Component Component

Collaboration

Signature-based Interface is insufficient.

Contextual Pointcut-based

InterfaceControl flow, Data flow, Trace match,

etc.

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Traditional Interface vs. Archface

Interface Expose methodsignatures

ArchfaceExpose program points

Method call

Coordinateexecution ofprogram points(Pointcut)

(Weave Advice)

ConnectionComponent

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Conceptual background

Join point

Architectural constraints can be specified by Pointcut & AdviceExtension of ccJava [Ubayashi, et al. 2007]

Three-part Modeling Framework[Masuhara, et al. 2003]

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Verifiable Bidirectional MDD

Not only programming-level but also design-level notion

ADL for bridging a gap between architectural design and implementation

Architectural Design

Archface

Program Code

Designs and verifies an architecture represented by Archface

Implements verified Archface

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1. MOTIVATION3. Archface for Java

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Archface as ADL

Observer Pattern represented by

Archface

ADL[Port notifyObservers]pointcut notifyObservers() : cflow(execution(void setState(String s))) && call(void notify());

[Port update]pointcut update():execution(void update());

[Connection]connects notifyChange (port1 :cSubject.notifyObservers, port2 :cObserver.update){ around() void :port1 { port2.proceed(); }}

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Archface as Program Interface

Archface(Program Interface)

Implement

Program Code(Implement exposed program points)

Type check+ formal verification+ test

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Bidirectional Traceability

Archface supports software evolution based on bidirectional traceability.

Archface can be considered as a protocol defined between architectural design and implementation.

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Integration with AO Archface supports not only OO but also

AO architecture. A weaving in AO can be realized by the

component-and-connector mechanism. We do not have to distinguish crosscutting

concerns from primary concerns at the architectural design phase.

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Example: Figure Editor

cDisplay cPoint

cLine

change

change

redraw

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Compiler construction

Archface definitions

Archface parser

AspectJ codegenerator

Aspect-Factoryclass generator

AspectJweaver

executable program

Archface compiler

AspectJ code (aspect)

Java code (class)

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1. MOTIVATION4. Discussion

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Related Work Architecture and Implementation:

– ArchJava [Aldrich, J. 2002]– Design pattern implementation in Java and AspectJ

[Hannemann, J. 2002] Co-evolution:

– Co-evolution between design and implementation [D'Hondt, T. 2001]

– Co-evolving the application design models after the code refactoring [Cazzola, W. 2007]

Aspect Component:– JAsCo [Suvee, D. et al. 2003]

Our approach is based on the interface mechanisms that not only enforce architectural constraints on the program implementation but also represent architectural abstractions.

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Open Issues

Which class of architecture is bi-directional ?– Currently, we consider control flow only…

Which class of architecture descriptions can be statically verified?

Which description should be tested?

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1. MOTIVATION5. Conclusion

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Summary

Archface is not only an ADL but also a programming-level interface mechanism.

The traceability between design and program code can be realized by enforcing architectural constraints specified in Archface on the program implementation.

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1. MOTIVATION

Thank you for your attention.