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Software Architecture: Introduction to the abstraction (May 2014_Split)
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Software Architecture: Introduction to the abstraction (May 2014_Split)

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This is an introductory presentation on Software Architecture that I made at the University of Split, in Croatia. …

This is an introductory presentation on Software Architecture that I made at the University of Split, in Croatia.
It shows what does it mean abstraction and why it is so important.


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  • 1. Università degli Studi dell’Aquila Henry Muccini DISIM, University of L’Aquila henry.muccini@univaq.it, @muccinihenry, www.henrymuccini.com @University of SPLIT, Croatia – May 2014
  • 2. 2 W E L C O M E
  • 3. The material in these slides may be freely reproduced and distributed, partially or totally, as far as an explicit reference or acknowledge to the authors is preserved. Henry Muccini
  • 4. Researcher at the University of L’Aquila, Italy Teaching 4
  • 5. Research Services 5
  • 6.  Closest airports: Rome Fiumicino, Rome Ciampino, Pescara  1 hour driving from Rome  45 mins driving to the cost  15 minutes driving to the mountains L’Aquila: where is it?
  • 7. Very close to… Pescara,Teramo, Giulianova, Alba Adriatica, Roseto,… Campo Imperatore, Campo Felice, Gran Sasso
  • 8. SOFTWARE ARCHITECTURE: INTRODUCTION TO THE ABSTRACTION 11
  • 9. Software Engineering Engineered Software SystemSoftware System
  • 10. Software Architecture Implementation Low Level Design Process: Architecture as an artefact Requirements Drives
  • 11. Process: Architecture towards the process • The architecture includes a collection of views • The architecture is NOT a single fase in the software development process Views Models Use Case Model Design Model Depl. Model Impl. Model Test Model Analysis Model
  • 12. The Software Architecture is the earliest model of the whole software system created along the software lifecycle  A set of components and connectors communicating through interfaces A set of architecture design decisions Focus on set of views and viewpoints Written according to architectural styles
  • 13. Software Architecture definitions Perry and Wolf, ’92 (aspects): →“Architecture is concerned with the selection of architectural elements, their interactions, and the constraints on those elements and their interactions necessary to provide a framework in which to satisfy the requirements and serve as a basis for the design.” →Elements are divided into processing elements, data elements and connection elements Garlan and Shaw, ’93 (elements): → Architecture for a specific system may be captured as “a collection of computational components - or simply components - together with a description of the interactions between these components - the connectors –”
  • 14. 18 Let us reason about the Gaudi’s Sagrada Familia
  • 15. The power of abstraction… 19
  • 16. STM-4/16 ADM ADM STM-1/4 ADM ADM ADM SXC 4/1 Urban Level SXA STM-1/4 ADM ADM ADM ADM STM-4/16 ADM ADM Regional level STM-1/4 ADM ADM ADM ADM SXA TELECOM ITALIA NETWORK ARCHITECTURE WDM STM-4/16 ADM ADM SXA WL STM-16 Ring National Level ADM ADM ADM ADM ADM ADM ADM ADM ADM WL ADM ADM ADM ADM ADM ADM ADM ADM ADM STM-16 Ring
  • 17. Java Development Tools Plugin Development Environment JFace SWT Workbench Workspace Runtime User Interface Core
  • 18. standard standard standard standard standard p r o c e s s laws
  • 19. Privacy e confidentiality Autenticity Need of Standards Shared Process Management Scalability Docs digitalization
  • 20. Architectural constraints and requirements Ideas Constraints Req1:.. Req2:.. Req3:.. ……… Architectural requirements C2 C3 C1 C4 Software Architecture Software Architecture synthesis Evaluation and Decisions making
  • 21. But which Architecture? Implications on privacy, confidentiality, performance, scalability, maintainability, etc.
  • 22. But which Architecture? Implications on privacy, confidentiality, performance, scalability, maintainability, etc.
  • 23. The Software Architecture is the earliest model of the whole software system created along the software lifecycle  A set of components and connectors communicating through interfaces A set of architecture design decisions Focus on set of views and viewpoints Written according to architectural styles
  • 24. Architecture Design Decisions Decisions about: Selected components/interfaces/connectors Distribution/Configuration of components/connectors Expected behavior SA Styles, Patterns and Tactics HW/SW/Deployment and other views Components’ Nesting and sub-systems NF attributes
  • 25. Architecture as a set of design decisions 29 A set of architecture design decisions taken to generate the architecture artifact Design problem sub- problem (or issue) sub- problem (or issue) Design option Design option Design option Design option Problem space Solution space Alternative solutions Alternative solutions Decision = best option Decision = best option Best, with respect to some criterion Jansen, A.; Bosch, J., "Software Architecture as a Set of Architectural Design Decisions," Software Architecture, 2005. WICSA 2005. 5th Working IEEE/IFIP Conference on , vol., no., pp.109,120, 2005. doi: 10.1109/WICSA.2005.61
  • 26. But, which is the right abstraction!?! 30
  • 27. the right abstraction… 31
  • 28. At which abstraction? Implications on privacy, confidentiality, performance, scalability, maintainability, etc.
  • 29. and, which is the right architecture!?! 34
  • 30. the right architecture… 35 Architectural constraints and requirements Ideas Constraints Req1:.. Req2:.. Req3:.. ……… Architectural requirements C2 C3 C1 C4 Software Architecture Software Architecture synthesis Evaluation and Decisions making The one that satisfies at best the requirements and constraints The “less” risky one
  • 31. The Software Architecture is the earliest model of the whole software system created along the software lifecycle  A set of components and connectors communicating through interfaces A set of architecture design decisions Focus on set of views and viewpoints Written according to architectural styles
  • 32. 38 Architectural Views User1 Router Server Timer AlarmUR AlarmRS (c) Check1 Nofunc Clock AckSR (c) AckRU1 User2 AlarmUR1 AlarmUR2 Check2 Check AckRU2 0 12 3 4 5
  • 33. ISO/IEC/IEEE 42010 - International Standard for Systems and Software Engineering – Architectural Description, 2011
  • 34. Logical View End-user Functionality Implementation (Development) View Programmers Software management Process View Performance Scalability Throughput System integrators Deployment View Conceptual Physical Use Case View Object Model of Design Static Organization of the Software Concurrency and Synchronization Software Mapping To HwSystem engineering System topology Delivery, installation Communication RUP 4+1 views
  • 35. Using multiple views has become standard practice in industry • IEEE Std 1471 (2000) -> … -> ISO/IEC/IEEE 42010 (2011) • Based on a survey we conducted with 48 practitioners [Survey2012], and about the usage of ALs in industry  85% uses multiple views [Survey2012] “What Industry needs from Architectural Languages: A Survey”, I. Malavolta, P. Lago, H. Muccini, P. Pelliccione, A. Tang (under review)
  • 36. The Software Architecture is the earliest model of the whole software system created along the software lifecycle  A set of components and connectors communicating through interfaces A set of architecture design decisions Focus on set of views and viewpoints Written according to architectural styles
  • 37. Prescriptive vs descriptive use of an architectural language
  • 38. “A set of design rules that identify the kinds of components and connectors that may be used to compose a system or subsystem, together with local or global constraints on the way the composition is done” (Shaw & Clements, 1996) A set of constraints you put on your development to elicit desirable properties from your software architecture. Topological Behavioral Communication-oriented etc. etc. IMP
  • 39. The Classical Style The Californian Style
  • 40. “A set of design rules that identify the kinds of components and connectors that may be used to compose a system or subsystem, together with local or global constraints on the way the composition is done” (Shaw & Clements, 1996) A set of constraints you put on your development to elicit desirable properties from your software architecture. Topological Behavioral Communication-oriented etc. etc. IMP
  • 41. Some Architectural Styles 47 Application Presentation Session Transport Network Data Link Physical Application Presentation Session Transport Network Data Link Physical Network Data Link Physical Network Data Link Physical
  • 42. but... why to care? 48
  • 43. Why to care? All the software systems have an architecture  All the critical/complex systems must have it carefully and explicitly specified Architecture-level decisions impact the scalability, performance, testability, functioning of the produced system Even if the code is perfectly written, a wrong architecture produces a wrong system
  • 44. Why to care? A wrong architecture produces a wrong system  Electronic Voting Systems  Bad architecting of FT software:  Tens of thousands of people around the large cities weren’t able to travel by train Thursday morning. No trains from and to Amsterdam and Airport Schiphol from early morning until after the morning rush hour. A failure in the back-up system was the cause. The system therefore didn’t start. And then the signals and switches could not be operated. Both primary and backup failed, hence no operations. (april 2012)  the Interim Report on Causes of the August 14th 2003 Blackout in the US and Canada clearly shows that the problem was mostly caused by badly designed fault tolerance, including various architectural issues: poor diagnostics of component failures, longer-than-estimated time for component recovery, failure to involve all necessary components in recovery, inconsistent system state after recovery, failures of alarm systems. (2003)  Denver Airport
  • 45. Why to care? The Best Jobs of 2014 “For the first time, our No. 1 job overall isn’t from the health care industry, it’s a tech job.” [http://goo.gl/WdxMjh]
  • 46. A bad architecture can imply a spaghetti code system
  • 47. 53
  • 48. Perry, D. E.; Wolf, A. L. (1992). "Foundations for the study of software architecture". ACM SIGSOFT Software Engineering Notes 17 (4): 40.doi:10.1145/141874.141884. Garlan & Shaw (1994). "An Introduction to Software Architecture". Retrieved 2012-09-13. ISO/IEC/IEEE (2011). "ISO/IEC/IEEE 42010:2011 Systems and software engineering -- Architecture description". Retrieved 2012-09-12. Kruchten, Philippe (1995, November). Architectural Blueprints — The “4+1” View Model of Software Architecture. IEEE Software 12 (6), pp. 42-50. Len Bass, Paul Clements, Rick Kazman: Software Architecture in Practice, Third Edition. Addison Wesley, 2012, ISBN 0-321-81573-4 (This book, now in third edition, eloquently covers the fundamental concepts of the discipline. The theme is centered around achieving quality attributes of a system.) 54