1. Software Engineering with Reusable Components
RiSE’s Seminars
Sametinger’s book :: Chapters 19, 20 and 21
Ana Paula Cavalcanti
November 29, 2018

2. Summary Reuse Measurement in Literate Programs (Chapter 19)
Motivation
Line and Word Runs
Case Study
Documentation Reuse (Chapter 20)
Source Code Inheritance
Documentation Inheritance
Conclusion (Chapter 21)
A Paradigm Shift
Limits of Component Reuse
Prospects
November 29, 2018

3. Reuse Measurement in Literate Programs
November 29, 2018

4. Provide and example of reuse measurement
Reuse Measurement in Literate Programs :: Chapter 19
Motivation
To focus is to determine the amount of ad-hoc reuse in literate programs (description of problems and solutions)
Provide and example of reuse measurement
Demonstrate the need fort systematic reuse of documentation
November 29, 2018

5. Reuse (l,len) = Identical (l.len) x 100
Reuse Measurement in Literate Programs :: Chapter 19
Line and Word Runs
Similarities and differences of texts have to be determined
Comparison of lines and words
Reuse (l,len) = Identical (l.len) x 100
Total (l)
L = line
Len = Length
high line reuse  Good indication of reuse
low line reuse, high word reuse  much reuse has taken place, modification
low reuse low, low word reuse  not much reuse
November 29, 2018

6. Case Study Reuse Measurement in Literate Programs :: Chapter 19
TEX :: converts plain text file containing document markup into a device independent graphics metafile
MetaFont :: reads a source file (metadescription) and does graphics interpretations
MetaPost :: file layouts as input and book quality figures as output
Systems
Lines
Words
TEX
21,541
122,137
MetaFont
20,481
109,307
MetaPost
20,460
104,375
Systems
Portion
R(l)
R(w)
TEX  MetaFont
100%
34.4%
14.3%
42.8%
21.5%
60.7%
MetaFont  MetaPost
80.8%
63.4%
78.5%
67.0%
85.1%
November 29, 2018

7. Case Study  consequences
Reuse Measurement in Literate Programs :: Chapter 19
Case Study  consequences
Reuse measurement based on line and word runs can be used for many different purposes
Evaluation of white-box reuse
Finding (legal/illegal) reuse in technical/scientific papers, determining the amount of modifications from one version of software to another
Finding potential locations for redesign
Finding the amount of “reuse” in programs handed in by students for programming courses
November 29, 2018

8. Documentation Reuse
November 29, 2018

9. Documentation Reuse :: Chapter 20
Motivation
Adequate documentation is mandatory for software maintenance as well as for economic reuse of software components. Overlapping information is typical both for source code and for documentation. Therefore, the inheritance mechanism should be applied to the documentation as well.
November 29, 2018

10. Source Code Inheritance
Documentation Reuse :: Chapter 20
Source Code Inheritance
A class may inherit structure and behavior of another class and additionally extend and modify it.
Methods
Classes
Rectangle
Shape
Draw
Outline
Move
Rotate
November 29, 2018

11. Documentation Inheritance
Documentation Reuse :: Chapter 20
Documentation Inheritance
Inherits the content of its base documentation
Chapters {Classes}
Sections {Methods}
Abstract Classes
Predefined structure for a certain group of elements guarantees uniform and consistent appearance
Information should not be spread over several files and/or directories {Inclusion and References}
November 29, 2018

12. Documentation Inheritance
Documentation Reuse :: Chapter 20
Documentation Inheritance
Information filtering is important for efficient access
Categories definition
Various views
To meet different documentation needs of various readers
Documentation Hierarchies
“The goal is to have software systems built from reusable components and to have their documentation built upon theses components’ documentation.”
November 29, 2018

13. Conclusion
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14. Conclusion :: Chapter 20 A Paradigm Shift
“There is still a long way to go until systematic reuse of software components, especially beyond company boundaries. It requires more research in various areas as well as commitment from companies to systematic reuse.”
“… unexpected discoveries may prove inconsistent with the prevailing paradigm. This may trigger a scientific revolution.”
Involve the development of new ideas, concepts, methods and problems…
Provides a way of doing software engineering better and more efficiently.
November 29, 2018

15. Software reuse and software components contribute to a paradigm shift in Software Engineering?
November 29, 2018

16. A Paradigm Shift  Software Components
Conclusion :: Chapter 20
A Paradigm Shift  Software Components
Components :: arbitrary reusable entities including macros and functions.
Component-based systems as a system that has components as primitive description units and communication between components as computation units.
November 29, 2018

17. A Paradigm Shift  Software reuse
Conclusion :: Chapter 20
A Paradigm Shift  Software reuse
Many new activities for software engineering are introduced through software reuse
Domain analyses
Development for/with reuse, reuse measurement
Reuse certification
Reuse classification
Repository compilation
Discipline concerned with construction related systems that share many commonalties and very in regular and identifiable ways
November 29, 2018

18. Limits of Component Reuse
Conclusion :: Chapter 20
Limits of Component Reuse
The most challenging aspect is component integration
Coordination
Communication
Interoperation
Can we raise abstraction levels of components and at the same time achieve high-performance systems by using these components?
November 29, 2018

19. Different way to build software systems
Conclusion :: Chapter 20
Prospects
Different way to build software systems
More productivity
The goal:: to evolve software
The landscape of software systems will constantly change from closed monolithic to open systems of reusable components.
November 29, 2018

20. References
SAMETINGER, J. Software Engineering with Reusable Components. Springer-Verlag, 1997.
November 29, 2018