ECOOP Workshop RAM-SE’09
Pointcut-based Architectural Interface
for
Bridging a Gap between Design and
Implementation
Naoyasu Ubayashi, Hidenori Akatoki, Jun Nomura
July 7, 2009
POSL (Principles of Software Languages) Gr.
Kyushu Institute of Technology, Japan
http://posl.minnie.ai.kyutech.ac.jp/
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Overview

Architectural design plays an
important role in the software
development.
– Robustness
– Reliability
– Maintainability

Archface
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; } }
Bug
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.
Bidirectional Traceability !
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Outline





Motivation
Archface
Archface for Java
Discussion
Conclusion
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1. Motivation
1. MOTIVATION
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Motivating example
Architectural Design
(Observer Pattern)
Architectural constraints
(Collaborative behavior)
are not preserved !
Code
public class Subject {
private String state = "";
Bug
public String getState() { return state; }
public void setState(String s) { state = s; }
…
}
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Solution ?
MDD + Code generation ?
 Fine, but …
Full code
generation
Program
Code
Detailed model
generation
Architectural design should be abstract !
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Problems to be tackled
In 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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Our Approach
Archface: architectural
interface for bridging a gap
between design modeling and
implementation
Archface
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; } }
Architectural information is
encapsulated in interfaces
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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
Interface
Control flow, Data flow,
Trace match, etc.
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Traditional Interface vs. Archface
Component
Interface
Archface
Connection
Expose method
signatures
Method call
Expose
program
points
(Pointcut)
Coordinate
execution of
program
points
(Weave Advice)
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Conceptual background
Three-part Modeling
Framework
[Masuhara, et al. 2003]
Join point
Architectural constraints can be specified by Pointcut & Advice
Extension of ccJava [Ubayashi, et al. 2007]
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Verifiable Bidirectional MDD
Not only programming-level but also
Architectural Design
design-level notion Designs and verifies an
architecture represented
 ADL for bridging a gap by
between
Archface
architectural design and
implementation

Archface
Implements verified
Archface
Program Code
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3. Archface for Java
1. MOTIVATION
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Archface as ADL
Observer Pattern
represented by
Archface
[Port update]
[Connection] pointcut update():
execution(void update());
connects notifyChange
ADL (port1 :cSubject.notifyObservers,
[Port notifyObservers]
pointcut notifyObservers()
port2: :cObserver.update){
cflow(execution(void setState(String
s))) &&
call(void notify());
around() void :port1
{ port2.proceed();
}
}
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Archface as Program Interface
Archface
(Program Interface)
Program Code
(Implement exposed program points)
Implement
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
redraw
cPoint
change
cLine
change
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Compiler construction
Java code
(class)
Archface definitions
Archface parser
Archface compiler
AspectJ code
generator
Aspect-Factory
class generator
AspectJ code
(aspect)
AspectJ
weaver
executable program
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4. Discussion
1. MOTIVATION
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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
Our refactoring
approach
is based
[Cazzola,
W. 2007]on the
interface
mechanisms
that not only enforce
Aspect Component:

– JAsCo [Suvee,constraints
D. et al. 2003]
architectural
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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5. Conclusion
1. MOTIVATION
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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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Thank you for your attention.
1. MOTIVATION
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