Advanced Software Engineering Course, University of L'Aquila This lecture explains a generic Architecting process to be followed when designing a software system. It also links the architecting process with agibility.

1. The Architecting Process (and the link with Agibility)
Henry Muccini
henry.muccini@univaq.it
DISIM
Dep.nt of Information Engineering, Computer Science and Mathematics
University of L’Aquila, Italy

2. The material in these slides may be freely reproduced
and distributed, partially or totally, as far as an explicit
reference or acknowledge to the material author is
preserved.
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Henry Muccini

3. Intro to SA
SA Case study
SA style
ADLs
Design Decisions
Views/Viewpoints
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Non Functional S.E.
Performance modeling
Performance analysis
UML
UML Profiling
Lab

4. SEA Group

5. SEA Group
Architectural constraints
and requirements
Ideas
Constraints
Req1:..
Req2:..
Req3:..
………
Architectural
requirements
C2
C3
C1
C4
Software
Architecture
Software
Architecture
synthesis
Evaluation and
Decisions making

6. SEA Group

7. SEA Group
Let us identify the system
requirements
Let us identify the
ARCHITECTURALLY RELEVANT
requirements

8. SEA Group
Let us identify subsystems

9. SEA Group
Let us identify the main
components and connectors

10. SEA Group
SA box&line informal
Modeling
AND/OR SA Formal Modeling
Incremental design

11. SEA Group
SA-based functional and
non functional analysis
SA-conformance to
requirements
Predictive analysis
Code-to-SA conformance
analysis

12. Patrizio Pelliccione, Paola Inverardi, Henry Muccini: CHARMY: A Framework for
Designing and Verifying Architectural Specifications. IEEE Trans. Software Eng.
35(3): 325-346 (2009)
Vittorio Cortellessa, Antinisca Di Marco, Paola Inverardi
Model-Based Software Performance Analysis.
First Edition, Springer, 2011.
Henry Muccini, Antonia Bertolino, Paola Inverardi: Using Software Architecture for
Code Testing. IEEE Trans. Software Eng. 30(3): 160-171 (2004)
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SA-based functional and
non functional analysis
SA-conformance to
requirements
Predictive analysis
Code-to-SA conformance
analysis
inputs

13. SEA Group
Coding based on the
defined SA
Systematic skeleton «code
generation»
SA as a reference artifact for
coding
inputs
C2SADL,
ArchJava, JavaA

14. SA
Design
Decisions
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AS Requirements with Quality
attributes
Subsystems
Components and Connectors
SA Modeling
SA Verification and Validation
SA-based coding

15. Decomposition
Designing to Architecturally Significant Requirements
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What happens to the other requirements?
Do I design for one ASR at a time or all at once?
Generate and Test
Hypothesis
Existing systems
Frameworks
Patterns and tactics
Domain decomposition
Design checklists

16. SEA Group
Attribute-Driven Design
Iterative method
«workable»
architecture
early and quickly
boundaries
Inputs:
correct set of ASRs
External systems, devices, users
Output:
Sketches of Architectural views
Agile
Step1:
Decomposition tree
you want or won’t pick «whole»
system as the starting point
breadth depth first
Step3:
Generate and test
Patterns, tactics, checklists

17. http://agilemanifesto.org/
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18. While it may not work for complex systems:
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 The principles reflect a process employed for small-to
medium-sized project
 Co-location or high level of communication
 Little attention to cross-cutting concerns
agility code-first
architecting
Up-front
design

19. Adding time for up-front
work reduces later rework
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But, how much?
Sweet spots:
.10ksloc -> no up-front
. …
.1000ksloc -> ~40%
Risk reduction

20. “If information isn’t needed, don’t spend the resources
to document it. All documentation should have an
intended use and audience in mind, and be produced in
a way that serves both.”
YAGNI = You ain’t gonna need it
“We document the portions of the architecture that we
need to teach to newcomers, that embody significant
potential risks if not properly managed, and that we
need to change frequently. We document what we
need to convey to readers so they can do their job.”
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[SAinPractice]

21. Web-based Video Conferencing
Process:
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 Initial software and system architecture
 Incremental implementation
 Starting with critical functionalities
 Architecture refactoring based on new requirements
 Continuous experimentation, empirical evaluation,
architectural analysis