Secret Assumption of Agile (Chinese)

Copyright © 2009 by Fred George 1

Tuesday, September 15, 2009

The Secret
Assumption
of Agile

Fred George
TrafﬁcBroker, Ltd., London, United Kingdom



Agile is Productive



Agile is Productive

Traditional

12 Months

$28 per Hour

$2,000,000



Agile is Productive

Traditional Agile

3
12 Months 8 .............
5
8

$28 $87
6x
per Hour

$2,000,000 $1,100,000



How?



How?

1. Code That Can Change

2. Lean Management

3. Processing Power



“Objects are only good for
programs that change.”

“
”
Rick DeNatale, IBM
1988



Stories Assume Easy Change




Story Story Story Story





Story Story Story


Story




Story

Story Story Story




Typical Program



Typical Program

public void foo( ) {
...
...
...
...
...
...
...
...
}


Typical Program

public void foo( ) { How many lines?
...
...
...
...
...
...
...
...
}


Typical Program

...
...
...
...
... 2.3
...
...
...
}


Typical Program

...
...
...
...
... 2.3
... 25
...
...
}


Typical Program

...
...
...
...
... 2.3
... 25
...
... Smalltalk:
} 1.1


Replacement Application



Old

Java

Oracle DB

Web UI



Old New

Java Java

Oracle DB Oracle DB

Web UI Web UI



Old New

Java Java

Oracle DB Oracle DB

Web UI Web UI

72 Classes



Old New

Java Java

Oracle DB Oracle DB

Web UI Web UI

72 Classes 1400 Classes



Tasking Cycle



Task Cycle Case Study




1,000,000 J2EE
50
8000




1,000,000 J2EE

2-4 50
8000



Tasking Cycle



Tasking Cycle

15



Tasking Cycle

15

15



Simple Design



Simple Design

1. Works



Simple Design

1. Works

2. Communicates



Simple Design

1. Works

2. Communicates

3. No duplicate code



Simple Design

1. Works

2. Communicates


4. Least classes and methods



Simple Design

1. Works

2. Communicates


4. Least classes and methods

Applies to Application and Tests



Refactoring
Martin Fowler



Tasking Cycle



Refactoring
to Patterns
Joshua Kerievsky



Tasking Cycle



Case Study: Complexity




Cyclomatic Complexity





100 100 is Bad





100 100 is Bad

“... 5 ”-
“...never seen less than 5” - Senior Architect





100 100 is Bad

“... 5 ”-

: 1.8 Cyclomatic Complexity





100 100 is Bad

“... 5 ”-

: 1.8 Cyclomatic Complexity

9 : 1 bug



Path to Proﬁciency



28
12

23 5
15



: 28
(Payback)
11 12

23 5
15



OO Boot Camp
OO



OO Boot Camp
OO
“... ...”

“...teaches you to think like a programmer...”



CIO

Lead Designer, Consulting Firm, commenting to CIO of a large US manufacturer.



“15 minutes after the class started, I realized I
knew nothing about programming.”

“ 15
”

CIO

Lead Designer, Consulting Firm, commenting to CIO of a large US manufacturer.



OO Boot Camp
OO



OO Boot Camp
OO
1995 History: Since 1995

1000 3 Over 1000 Students; 3 countries



OO Boot Camp
OO


Java, VB, C#, Ruby



OO Boot Camp
OO


Java, VB, C#, Ruby

Socratic Method (Question - Answer - Question)



OO Boot Camp
OO


Java, VB, C#, Ruby

Socratic Method (Question - Answer - Question)

60% 60%+ Lab

Pair Programming

15 Test First (15 Minute Cycle)

Students Present Solutions



2-6



2

2-6



Part 1: Principles



Part 1: Principles

Encapsulation Collaborating Objects

Object Relationships Interfaces

Inheritance Coding Patterns

Delegation Refactoring

Polymorphism Recursion



Part 1: Principles

Encapsulation Collaborating Objects

Object Relationships Interfaces

Inheritance Coding Patterns

Delegation Refactoring

Polymorphism Recursion

40-50


Part 2: Design Patterns




Rationale Composite Pattern

vs. Patterns vs. Visitor Pattern
Principles
Builder Pattern
Observer Pattern

Concerts
Iterator Pattern

Survey of Patterns
Mediator Pattern




Rationale Composite Pattern

vs. Patterns vs. Visitor Pattern
Principles
Builder Pattern
Observer Pattern

Concerts
Iterator Pattern

Survey of Patterns
Mediator Pattern

40-50


Suspicious Statements




case - Almost always wrong





else - Mostly wrong





else - Mostly wrong

if - Suspicious

Unless guard clause at start of
method





else - Mostly wrong

if - Suspicious

Unless guard clause at start of
method

Substitute Design Patterns for all these



Suspicious Methods



Suspicious Methods

getters - Violates Encapsulation



Suspicious Methods


setters -
Worse: violates Encapsulation and Object integrity



Suspicious Methods


setters -
Worse: violates Encapsulation and Object integrity

2 Methods with 2 or more levels of indenting



Suspicious Classes



Suspicious Classes

Special naming conventions for Interfaces



Suspicious Classes


Interface with a single implementing Class



Suspicious Classes


Interface with a single implementing Class

2
Classes with more than 2 instance variables



Results



Results

Dropouts 20%

Journeymen 20%

Predictors

Retention
Must be used within a month

Support
Journeymen, Masters



Maintenance



Maintenance
Old New

Java Java

Oracle DB Oracle DB

Web UI Web UI

72 Classes 1400 Classes



Transition Plan



Transition Plan

No Documentation

No Training

No Time



Transition Plan

No Documentation

No Training

No Time

No Problem!



Team with Pair
Programming



Secret Assumption of Agile (Chinese)

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