Software Engineering with Reusable Components

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Software Engineeringwith Reusable Components

• RiSEs Seminars
• Sametingers book Chapters 1, 2 and 3
• Vinicius Cardoso Garcia

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Summary

• Introduction (Chapter 1)
• Software Components
• Software Reuse
• Software Reuse (Chapter 2)
• Introduction and Motivation
• Benefits and Obstacles of Software Reuse
• Technical Aspects of Software Reuse (Chapter 3)
• Reuse Facets

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1. Introduction
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Introduction Chapter 1

• Start -gt simple programs and implementing
  algoritms
• Complexity -gt software crisis
• Reuse of software components
• Several advantages
• What are components, their proprieties,
  requirements, implications

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Software Components
Introduction Chapter 1

• Algorithms, designs, requirements,
  specifications, procedures, modules,
  applications, ideas, among others

components are artefacts that we clearly
identify in our software systems. They have an
interface, encapsulate internal details and are
documented separately

• CBSD has become a buzzword
• Be easily combined with each other

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Introduction Chapter 1

• Reuse component integrate it into a software
• Example what to do to reuse a algorithm?
• Problems?
• Implement reuse idea (pseudocode), programming
  language
• Component ?

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What is not a component? Why?
Introduction Chapter 1

• A software design is not a software component
• Framework is not one component as a whole
• Consists of many components
• Design patterns are not a software components
  too!
• Can be reused but they are not a software
  components
• Solve certain problems by arranging components
  (classes)

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The reuse of software designs is more effective?
Introduction Chapter 1

• Depends on what a component is
• Restrict to source code components
• Increase productivity
• reuse a component reusing design
• Components x Algorithms reuse
• Components have an interface -gt black-box reuse
  (white-box)
• Documentation is a necessity
• Code scavenging more complex, more difficult
  to reuse

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Software Reuse
Introduction Chapter 1

• Soft. Component and Soft. Reuse relation
• The use of soft. component is not sufficient
• Reusing soft. influence on Soft. Engineering
• Structures and economic
• Soft. Life cycle domain analysis

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Reuse legacy code, is possible?
Introduction Chapter 1

• New challenges !
• Requirements change constantly rebuilding every
  time?
• Incorporate old components
• Reengineering, Reverse engineering, Refactoring,
  CBSD, CASE tools, Software Transformations, AOSD
• (Alvaro et al., 2003), (Garcia et al., 2004) and
  (Garcia, 2005)

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Soft. systems must be composed of components
Introduction Chapter 1

• Black-box reuse is inflexible and restrictive
  (Prieto, 1994)
• Reuse of source components -gt reuse of analysis
  and design (implicitly) (Freeman, 87a)
• Explicitly misses the opportunity of reusing
  this information
• Soft. Reuse and Soft. Component will not salve
  all the problems in SE
• Flexible software systems, evolution and
  adaptability

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2. Software Reuse
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History of Software Reuse
Software Reuse Chapter 2

• Software crisis late sixties development and
  maintenance
• McIlroy software factory concept
• Academia late 1970s
• 1980s large-scale reuse programs were done
• Advances repositories, classification tech.,
  creation and distribution, environments

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Introduction and Reuse Definitions
Software Reuse Chapter 2

• Code scavenging -gt increased productivity
• source code generators or reuse knowledge
• Many different viewpoints
• Reuse is the use of any information which a
  developer may need in the software creation
  process (Freeman, 1987a)
• the use of everything associated with a software
  project, including knowledge (Basili and
  Rombach, 1988)

Software reuse is the process of creating
software systems from existing software rather
than building them from scratch. (Krueger, 1992)
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Motivation
Software Reuse Chapter 2

• 40 to 60 of code is reusable
• 60 of design and code are reusable in business
  application
• 75 of program functions are common
• 15 of the code is unique
• 15 to 85 - rates of actual and potential reuse
  (Mili et al, 1995)

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Benefits of Software Reuse
Software Reuse Chapter 2

• Quality Improvements
• Quality, productivity, performance, reliability,
  interoperability
• 9 times better during component test and 4.5
  during system test. Other project no errors found
  in life cycle (Bauer, 1993)
• Effort reduction
• Redundant work, development time, time to market,
  documentation, maintenance costs, training costs,
  team size
• Other Benefits
• Rapid prototyping support, expertise sharing

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Industry examples
Software Reuse Chapter 2

• NASA 25 projects (3K to 112K LOC) 32 reused
• Motorola candidate technology for initiatives
  and goals to improve productivity and quality
• HP reduction in defect density range from 24
  to 76 and a 40 to 57 increase in productivity
• IBM Reuse Tecnology Center, saving in the
  millions of dollars, reusing accounting for 20
  to 30
• Other examples 1979 to 1992 (Mili et al, 1995)

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Obstacles to Software Reuse
Software Reuse Chapter 2

• Many factor directly or indirectly influence the
  success or failure of reuse
• Technical, conceptual, organizational, economic,
  etc
• Managerial and Organizational
• Lack of management support, project management,
  lack of explicit procedures, inadequate
  organizational structures, not invented here,
  legal issues, lack of management incentives

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Obstacles to Software Reuse
Software Reuse Chapter 2

• Economic Obstacles
• Can save money in the long run, but is not for
  free
• Costs of making something reusable, costs of
  reusing it and costs of defining and implementing
  a reuse process
• Conceptual and Technical Obstacles
• Difficult on finding reusable software,
  nonreusability of found software, legacy
  components not suitable for reuse, OO technology,
  modification, integration, garbage reuse
• Other basic technical difficulties
• What a reusable component constitute? What a
  component does and how to use it?

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3. Technical Aspects for Software Reuse
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Reuse facets
Technical Aspects for Soft Reuse Chapter 3

• Affected by nontechnical and technical aspects
• Substance defines the essence of reused items
• Scope defines the form and extent of reuse
• Mode defines how reuse is conducted
• Technique defines the approach that is used to
  implement reuse
• Intention defines how elements will be used
• Product defines what is reused

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Reuse Techniques
Technical Aspects for Soft Reuse Chapter 3

• Abstraction
• Specification (what) and realization (how)
• Compositional Reuse
• Components remain unmodified in their reuse
• Repositories principles of organization (pipe
  architecture or OO)
• Locate components, classification schemes,
  retrieval techniques, integrate them in software
  systems
• Component composition
• Code and design scavenging

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Generative Reuse
Technical Aspects for Soft Reuse Chapter 3

• Reuse of a generation process
• Lexical analyzers, parsers and compilers
• Application generators
• Language-based generators
• Transformation systems
• Draco approach domain-oriented specifications
  (Garcia, 2005)
• Programming languages

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Generation vs. Composition
Technical Aspects for Soft Reuse Chapter 3
Reuse Techniques Composition Generation
Reused component Building blocks Patterns
Nature of component Atomic and immutable, passive Diffuse and malleable, active
Emphasis Repositories, composition principles Generators, language-based generators, TS
Examples Function/class libraries, Unix filters Parser generators, 4th generation languages
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Reuse Intentions
Technical Aspects for Soft Reuse Chapter 3

• Black-box reuse
• White-box reuse
• Glass-box reuse
• Generative reuse
• Specification -gt implementation

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Reuse products
Technical Aspects for Soft Reuse Chapter 3

• Algorithms
• Function and Class libraries
• Software architectures and designs
• Framework Classes
• Design patterns
• Applications
• Documentation

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References

• SAMETINGER, J. Software Engineering with Reusable
  Components. Springer-Verlag, 1997.
• ALVARO, A. et al. Orion-RE A Component-Based
  Software Reengineering Environment. In
  Proceedings of The 10th Working Conference on
  Reverse Engineering (WCRE'2003), 2003, Victoria,
  British Columbia, Canada.
• GARCIA, V. C. et al. Towards an effective
  approach for Reverse Engineering. In the 11th
  IEEE Working Conference on Reverse Engineering
  (WCRE 2004 Conference), 2004, Delft University of
  Technology, Netherlands.
• GARCIA, V. C. Phoenix An Approach for
  Aspect-Oriented Software Reengineering. Master
  thesis. Federal University of São Carlos
  (UFSCar), São Carlos-SP, Brazil. March, 03 2005.
  (in portuguese)
• PRIETO, R., Historical Overview. In Software
  Reusability, chapter 1, pages 1-16, 1994.
• FREEMAN, P. Reusable software engineering
  concepts and research directions. In Tutorial
  Software Reusability, pages 10-23. 1987.
• BASILI, V. R. and ROMBACH, H. D. Towards a
  comprehensive framework for reuse A
  reuse-enabling software evolution environment.
  Technical Report CS-TR-2158, University of
  Maryland, December 1988.
• MILI, H. et al. Reusing Software Issues and
  research directions. IEEE Transactions on
  Software Engineering, 21(6)528-562, June 1995.
• BAUER, D. A. A reusable parts center. IBM Systems
  Journal, 32(4)620-624, 1993.