1. Introduction To Software Component Reuse
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Peter Raeth
Ball Aerospace & Technologies Corp.

2. Overview Introducing software component reuse
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Introducing software component reuse
Important part of software projects
Potential to reduce duplication of effort
Organized approach essential to succeed

3. Topics of Discussion Definition Benefits Costs Assets for Reuse
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Definition
Benefits
Costs
Assets for Reuse
Elements of Reuse
Basic Reuse Process
Project Approach
Summary
References

4. Definition
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Software component reuse is a process whereby previously created automation assets are employed by a new project as a means of improving the quality and decreasing the cost of system development.
Software component reuse is the employment of existing automation assets to meet new requirements.

5. Benefits of Reuse Cheaper products Higher quality Fewer errors
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Cheaper products
Higher quality
Fewer errors
Less new code
Simpler testing
Faster response to tasking
Baseline of proven code, designs, plans

6. Some Statistics
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Effective construction of software from reusable parts can reduce development cost 40%
Reuse can reduce life cycle cost 50%
Reuse can reduce problem rates by factor of 10

7. The Flip Side Staff retraining Staff reluctance
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Staff retraining
Staff reluctance
Creating, documenting, & managing a repository
Identifying reusable assets
Cost to create reusable assets (1.25 times normal)
Requires evolution
organization
process
assets
Unplanned reuse programs typically fail

8. Hierarchy of Reuse Requirements Specification Design Code
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Requirements
Specification
Design
Code
modules
functions
classes
Documentation

9. Fundamental Elements Repositories Componentry Re-engineering
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Repositories
storing, cataloguing, and retrieving assets
Componentry
partitioning and integrating software modules
Re-engineering
adapting existing software to new applications
Domain modeling
analyzing requirements relative to existing assets
Frameworks
known configurations of components and subsystems available to development teams

10. To Proceed Must move beyond casual or opportunistic reuse
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Must move beyond casual or opportunistic reuse
Commitment and follow up is needed
from technical staff
from management
Planned and managed processes are foundation
for developing reusable assets
for exploiting existing assets

11. Three Basic Approaches
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Write original code with reuse in mind
Re-engineer existing assets for reuse
Purchase reusable libraries

12. Basic Processes Development WITH reuse Development FOR reuse
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Development WITH reuse
search for, evaluate, adapt, and integrate existing and appropriate knowledge, specifications, designs, code, tests, and documentation to deliver quality products in shorter time at lower costs
Development FOR reuse
identify what is potentially and viably reusable
design, qualify, construct, and classify software artifacts for reuse in solutions other than those initially targeted

13. Recommended Approach Identify modules to incorporate in common library
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Identify modules to incorporate in common library
Consolidate similar modules
Ensure adequate documentation for each module
Establish version control for resulting collection
Establish coding standards for new code or mods
Re-engineer code for structured framework
Incorporate structured code into new object-oriented framework as class functionality
Build all new code for object-oriented framework
Maintain reuse mindset when adding new functionality to analyst workbench

14. Summary Plenty of value in reuse mentality
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Plenty of value in reuse mentality
Need patience with extra up-front effort
Exercise discipline regarding common library
Trying to facilitate effective reuse process
Hoping to earn evolution in people’s thinking

15. References
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Gustafson, David, A., Course notes on software reuse, Kansas State University, Department of Computing and Information Science, Apr 98
Corporate authors, “Software Reuse - A Concise Guide”, European Software Institute, Apr 98
Nulden, Urban, “The Why, What, and How of Reuse in Software Development”, white paper, Department of Informatics, Göteborg University, Sweden, Apr 98
ADDITIONAL MATERIAL
Conn, Richard, “SE Software Reuse, Course Material”, Software Engineering Department, Monmouth University, Apr 98
Menzies, Tim, “Introduction to Object-Oriented Analysis and Design - Course Material”, University of South Wales, Jul 97