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DESCRIPTION
Early proponents of Agile assumed a certain style of programming that was an outgrowth of the Simple Design practice of eXtreme Programming. As Agile has been adopted, this particular style was not brought in as a co-requisite. This presentation explains aspects of this style, cites examples of the impact of its use, and describes a training program developed by Fred George to address this deficiency. This training program formed the basis of ThoughtWorks University several years after its creation. (Presentation given at Agile India 2013)
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Copyright © 2009-2013 by Fred George
The Secret Assumptionof Agile
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Fred Georgefredgeorge@acm.org@fgeorge52
Copyright © 2009-2013 by Fred George
Agile is Productive
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Traditional
12 Months
$28 / Hour
$2,000,000
Agile
8 Months.............3 Months5 Months8 Months
$87 / Hour
$1,100,0006x
Copyright © 2009-2013 by Fred George
How?
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1. Code That Can Change2. Lean Management3. Processing Power
Copyright © 2009-2013 by Fred George
“Objects are only good for programs that change.”Rick DeNatale, IBM1988
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Copyright © 2009-2013 by Fred George
Stories Assume Easy Change
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Copyright © 2009-2013 by Fred George
Typical Program
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public void foo( ) {........................
}
How many lines?
2.3 lines / method25 lines / class
Smalltalk:1.1 lines / method
Copyright © 2009-2013 by Fred George
Replacement Application
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Old
Java
Oracle DB
Web UI
72 Classes
New
1400 Classes
Java
Oracle DB
Web UI
Copyright © 2009-2013 by Fred George
Tasking Cycle
8
TaskDesign
TestCode
Integrate
Ship
Copyright © 2009-2013 by Fred George
Task Cycle Case Study
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TaskDesign
TestCode
Integrate1,000,000 Lines of J2EE Code50 Programmers4000 TestsCycle Time?
2-4 Hours
Copyright © 2009-2013 by Fred George
Tasking Cycle
10
TaskDesign
TestCode
Integrate
15 Minutes
15 Minutes
Copyright © 2009-2013 by Fred George
Simple Design
1. Works
2. Communicates
3. No duplicate code
4. Least classes and methods
Applies to Application and Tests
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Copyright © 2009-2013 by Fred George
RefactoringMartin Fowler
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Copyright © 2009-2013 by Fred George
Tasking Cycle
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TaskDesign
TestCode
Integrate
SimpleDesign
Refactoring
Copyright © 2009-2013 by Fred George
Refactoring to PatternsJoshua Kerievsky
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Copyright © 2009-2013 by Fred George
Refactoring
IntroducePatterns
Refactoring
Tasking Cycle
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TaskDesign
TestCode
Integrate
Copyright © 2009-2013 by Fred George
Case Study: Complexity
Cyclomatic Complexity
100 is Bad
“...never seen less than 5” - Senior Architect
Cyclomatic Complexity: 1.8
9 week test: 1 bug, fixed within 2 hours
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Copyright © 2009-2013 by Fred George 18
Path to Proficiency
Workin
g
Experience
Training
Copyright © 2009-2013 by Fred George
Product Requests (London)
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23 Stories15 Days
28 Stories12 Days
Class5 Days
Payback:11 Days
Copyright © 2009-2013 by Fred George
OO Boot Camp
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“...teaches you to think like a programmer...”
Copyright © 2009-2013 by Fred George 21
“15 minutes after the class started, I realized I knew nothing about programming.”Lead Designer, Consulting Firm, commenting to CIO of a large US manufacturer.
Copyright © 2009-2013 by Fred George
OO Boot Camp
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History: Since 1995
Over 1000 Students; 3 countries
Java, VB, C#, Ruby
Socratic Method (Question - Answer - Question)
60%+ Lab
Pair Programming
Test First (15 Minute Cycle)
Students Present Solutions
Copyright © 2009-2013 by Fred George
Master
Journeyman
Apprentice
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Copyright © 2009-2013 by Fred George 24
Master
Journeyman
Apprentice
2-6 Months
2 Years - Never
Copyright © 2009-2013 by Fred George
Part 1: PrinciplesEncapsulation
Object Relationships
Inheritance
Delegation
Polymorphism
Collaborating Objects
Interfaces
Coding Patterns
Refactoring
Recursion
25
40-50 Hours
Copyright © 2009-2013 by Fred George
Part 2: Design PatternsRationale
Patterns vs. Principles
Observer Pattern
Iterator Pattern
Mediator Pattern
Composite Pattern
Visitor Pattern
Builder Pattern
Concerts
Survey of Patterns
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40-50 Hours
Copyright © 2009-2013 by Fred George
Suspicious Statements
case - Almost always wrong
else - Mostly wrong
if - Suspicious
Unless guard clause at start of method
Substitute Design Patterns for all these
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Copyright © 2009-2013 by Fred George
Suspicious Methods
getters - Violates Encapsulation
setters - Worse: violates Encapsulation and Object integrity
Methods with 2 or more levels of indenting
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Copyright © 2009-2013 by Fred George
Suspicious Classes
Classes with names ending in -er or -or
Special naming conventions for Interfaces
Interface with a single implementing Class
Classes with more than 2 instance variables
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Copyright © 2009-2013 by Fred George
Results
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Dropouts
Journeymen
Predictors
Retention
Support
20%
20%
Architecture, Design, Multiple Languages
Must be used within a month
Journeymen, Masters
Copyright © 2009-2013 by Fred George
Maintenance
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Old
Java
Oracle DB
Web UI
72 Classes
New
1400 Classes
Java
Oracle DB
Web UI
Copyright © 2009-2013 by Fred George
Transition Plan
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No Documentation
No Training
No Time
No Problem!
Copyright © 2009-2013 by Fred George
Training -- OO Boot Camp
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First class 1 October
9-12 students / class
Include project managers and QA
4 classes so far
Copyright © 2009-2013 by Fred George
Implementation
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Start development on 15 October
Ruby used (never used before 1 October)
No stories - just business problem
First page ready for review by end of November
Copyright © 2009-2013 by Fred George
Currently...
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5 Tables running
Each Table has it’s own business problem
Only developers
Speaker designated
Processes are varying, particularly metrics
Copyright © 2009-2013 by Fred George
Questions?
36
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