1 Archface: Architectural Interface -- Bridging a Gap between Design Modeling and Implementation Naoyasu Ubayashi, Hidenori Akatoki, Jun Nomura Kyushu Institute of Technology, Japan May 17, 2009 MISE’09

Motivation  Architectural design plays an important role in the software development. Robustness Reliability Maintainability  However, 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; and deal with software evolution. 2 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; } } Program Code Bidirectional Traceability ! Architecture Bug

Our Approach 3 Architecture Program Code Archface  Archface: architectural interface for bridging a gap between design modeling and implementation  Archface integrates not only design modeling with its implementation but also AO with OO. Architectural information is embedded into interfaces 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; } }

Architecture Descriptions Supported by Archface  Component-and-Connector Architecture  Collaborations among Components 4 Component Collaboration Signature-based Interface is insufficient. Contextual Pointcut-based Interface Control flow, Data flow, Trace match, etc.

Verifiable Bidirectional MDD Not only programming-level but also design-level notion ADL for bridging a gap between architectural design and implementation 5 Architectural Design Archface Program Code Designs and verifies an architecture represented by archface Implements verified archface

Archface as ADL 6 Observer Pattern represented by Archface ADL

Archface as Program Interface 7 Archface (Type) Implement Program Code Type check + formal verification + test

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? 8

Appendix 9

Layered Model 10 Component Connection Component-and-Connector Architecture Contextual Info. Control/Data flow, etc. Contextual Info. Control/Data flow, etc. Type Check (Port check) Type Check (Port check) Alloy (Instance-level connection) Alloy (Instance-level connection) Model Checking (Behavior) Model Checking (Behavior) Test Verification/Validation

Related Work  ArchJava [Aldrich, J. et al. 2002]  Design pattern implementation in Java and AspectJ [Hannemann, J. 2002] 11