ch03 Basing Software Development on Reusable Technology.ppt

Object-Oriented Software EngineeringPractical Software Development using UML and Java
Chapter 3:
Basing Software Development on
Reusable Technology
© Lethbridge/Laganière 2001
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Chap. 3: Basing Development on Reusable Technology
Building on the Experience of Others
Software engineers should avoid re-developing software already developed
Types of reuse:
Reuse of expertise
Reuse of standard designs and algorithms
Reuse of libraries of classes or procedures
Reuse of mands built into languages and operating systems
Reuse of frameworks
Reuse plete applications
© Lethbridge/Laganière 2001
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Chap. 3: Basing Development on Reusable Technology
Reusability and Reuse in SE
Reuse and design for reusability should be part of the culture of software anizations
But there are problems to e:
Why take the extra time needed to develop something that will benefit other projects/customers?
Management may only reward the efforts of people who create the visible ‘final products’.
Reusable software are often created in a hurry and without enough attention to quality.
© Lethbridge/Laganière 2001
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Chap. 3: Basing Development on Reusable Technology
A vicious cycle
Developers tend not develop high quality ponents, so there is often little to reuse
To solve the problem, recognize that:
This vicious cycle costs money
Investment in reusable code is important
Attention to quality of ponents is essential
So that potential reusers have confidence in them
The quality of a software product is only as good as its lowest-quality ponent
Developing ponents can often simplify design
© Lethbridge/Laganière 2001
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Chap. 3: Basing Development on Reusable Technology
Frameworks: Reusable Subsystems
A framework is reusable software that implements a generic solution to a generalized problem.
It mon facilities applicable to different application programs.
Principle: Applications that do different, but related, things tend to have quite similar designs
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