For Agile Thailand 2013, June 2, 2013

1. Agile with Legacy Product
Copyright 2013
Suradet Jitprapaikulsarn
www.ajarnsuradet.com

2. Revision 1.0 Agile with Legacy Product 2
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About Presenter
• Suradet Jitprapaikulsarn, Ph.D.
• Lecturer
• Department of Electrical and Computer
Engineering, Naresuan University,
Phitsanulok
• Email: suradet.j@gmail.com
• Facebook: Suradet Jitprapaikulsarn

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About Me (Cont.)
• Apply PSP since 1997
• Apply TDD since 1999
• 1st
Thai ScrumMaster, since 2009
• Was the only authorized PSP instructor in
Southeast Asia
• 1st
Thai Certified PSP developer
• 5 times CMMI appraisal team member
• Only Asian instructor invited for Software
Architecture workshop at SEI, 7 year in a row
(2006 – 2012)

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Topics
• What is a Legacy Product?
• Typical Problems
• Why change?
• Issues
• An Approach
• Tools & Techniques

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What is a Legacy Product?
• Any system currently in production upon
which a business process depends
– Kent J. McDonald, Legacy System Migration
in an Agile Manner, 2008
• Product without tests
– Michael Feathers, Working Effectively with
Legacy Code, 2005
An existing product that needs changes
Suradet, 2013

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Typical Problems
• Production system
• No documents
• Developers gone
• Third party products

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Why change
• Fix
• Optimize
• Sustain
• Re-platform
• Decommission
• Refactor
• Consolidate
• Extend/Enhance
• Migrate
• Replace
Adapted from Capgemini,
Agile Legacy Lifecycle, 2011
and
Michael Feathers, Working
Effectively with Legacy Code, 2005

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Impacts of changes
• Functionality
• Quality Attributes
• Structure
• Resource Usage

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Issues
• Technical
• Management
• Organizational

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An Approach
• Identify the change types
• Identify the interactions of the changes
• Identify the legacy assets
• Analyze the interaction
• Keep it agile

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A Legacy Code Change Algorithm
• Identify change points
• Find test points
• Break dependencies
• Write tests
• Make changes and refactor
Michael Feathers, Working
Effectively with Legacy Code, 2005

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Tools
• Documentation tools
• Refactoring tools
• Unit testing tools
• General testing tools

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Techniques
• Breaking Dependencies
• Seam model
– A place where behavior can be altered without
editing the code at the point of change
• Sprout Method
• Wrapper