Reengineering and Reuse of Software

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Re-engineering and Reuse of Software

• By
• Alex Kirzhner

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(No Transcript)
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Agenda

• Introduction
• Historical Information
• Re-engineering
• Software Reuse
• Component-based engineering
• Examples of reuse projects
• Non technical information
• Additional info and reference

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Problems

• Unused ideas
• Unused tools
• Abundant or out of date projects
• Development cost
• Maintenance cost

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Solution

• Re-engineering
• The process of examining and altering an
  existing system to reconstitute it in a new form.
  May include reverse engineering (analyzing a
  system and producing a representation at a higher
  level of abstraction, such as design from code),
  forward engineering (using software products
  derived from an existing system, together with
  new requirements, to produce a new system), and
  translation (transforming source code from one
  language to another or from one version of a
  language to another).
• Software Reuse
• The principle of using a software component
  in multiple applications, for example by deriving
  application-specific object classes from
  general-purpose object classes, or using existing
  class libraries or frameworks for common
  application functions. Reuse is one of the goals
  of object technology.

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Historical background

• Code reuse started with the first line of code.
• High-level languages introduce component and
  packages reuse, reengineering and reverse
  engineering.
• Reuse as a concept was introduced by McIlroy in
  1968.
• Reverse engineering and re-engineering as a
  concepts were introduced in 1980s

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Re-engineering

• Formal transformation popular in Europe
• Mainly used for forward and backward
  engineering.
• Reverse engineering assist in understating of
  components.
• Informal transformation popular in US
• Pattern matching methods use reverse
  engineering.

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Software Reuse

• Need component repository (i.e. component
  library) that easy to search
• Better knowledge about application (domain
  analysis)
• Each component need to have
• clear specification (parameters, method
  name), description
• author name and contact info, modification
  history
• Reuse components need to be as generic as
  possible.

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Component-based engineering

• Main goals
• decrease development time
• decrease development cost
• maintain high quality
• It can be achieved by component reuse
• Components are binary, independently deployable
  building blocks, that can be composed by third
  party 2

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Package based software development

• Source code components standardized build
  interface and configuration interface
• Source tree composition combining components
  into directory hierarchy
• Development and deployment modes
• Release management for deployed components
• Combined development during development mode
• Use of multiple SCM systems

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Concepts of Source tree composition

• Build Interface make component build interface
  standardized (this makes software building
  easier)
• Configuration interface make configuration
  interface standardized
• Component dependencies both dependency and
  variability parameters need to be present in
  configuration interface
• Build order first build all components that a
  component depends on.
• Component configuration multiple configuration
  parameters may exist for single component (makes
  component more generic)
• Source code packages done to get away from SCM
  dependency and allows to maintain multiple
  versions of the same component
• Package definitions contain main information
  about a component

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Concepts of Source tree composition
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Projects

• REBOOT (Reuse Based on Object-Oriented
  Techniques) - develops, evaluates and
  disseminates advanced methodologiesfor
  reuse-driven and object-oriented software
  development
• REDO assist software engineers in the
  maintenance, restructuring and validation of
  large software systems and their transportation
  between different environments. (On of the Esprit
  projects)
• ITHACA-2 assist in development of an integrated
  application support system based on the
  object-oriented programming approach.
• DRACO.NET - monitors your source code repository,
  automatically rebuilds your project when changes
  are detected and then emails you the build result
  along with a list of changes since the last
  build.

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Non technical issues

• Personnel
• Not everyone likes to reuse code written by
  someone else
• Buy vs. in-house development
• Reusable components take time from main
  project
• Economics
• Payoff for components reuse will occur in the
  long run (various metrics are used) see 3
• Software reuse through sale of packages
• Legal
• Re-engineering is illegal

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Measures for Reuse Success

• Reuse Benefit operational benefit of reuse
  (development effort and cost, time-to market,
  maintenance effort)
• Strategic Impact same as reuse benefit but on
  organizational level
• Software Quality measure error rate

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Additional Information

• Conferences
• The International Conference on Software
  Engineering
• The Symposium on Software Reusability
• The European Reuse Workshop

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Additional Information (cont.)

• Subscription Groups
• Software Reuse Factors
• Reusable Software Components Resources
• IEEE Software Reuse Group
• Software Productivity Consortium members

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References

• The Re-engineering and Reuse of Software
  Patrick A.V. Hall and Lingzi Jin. (Software
  Engineering Vol 1 p.355)
• Package-Based Software Development Merijn de
  Jonge, Proceeding of the 29th EUROMICRO
  Conference (EUROMICRO03)
• Analytical and Empirical Evaluation of Software
  Reuse Metrics Prem Devanbu, Proceeding of the
  18th International Conference on Software
  Engineering (ICSE96) p. 189
• Strategies for Software Reuse A Principal
  Component Analysis of Reuse Practices Marcus A.
  Rothenberger, IEEE Transaction on Software
  Engineering, Vol. 29 No. 9, September 2003 p.825

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Questions