Agile and Frameworks

HOW FRAMEWORKS CAN KILL YOUR AGILE PROJECTS
Sander Hoogendoorn | Principal Technology Officer, Global Agile Thought Leader | Capgemini
www.sanderhoogendoorn.com | sander.hoogendoorn@capgemini.com | @aahoogendoorn

SANDER HOOGENDOORN
Capgemini
Principal technology officer
Global agile thought leader
Chief architect Accelerated Delivery Platform (ADP)
Other
Author books on UML, agile
Author +200 articles, columns
Speaker +100 international conferences and seminars
Microsoft Partner Advisory Council .NET
Editorial boards & Advisory boards
Capping IT Off Blog
Web
www.sanderhoogendoorn.com
www.ditisagile.nl | www.smartusecase.com
sander@ditisagile.nl
@aahoogendoorn @ditisagile

2 HOW FRAMEWORKS CAN KILL YOUR AGILE PROJECTS
©2012 Sander Hoogendoorn. All Rights Reserved

AGENDA

An short story How frameworks can Software architecture
about frameworks get you in trouble versus frameworks

The layer Introducing the The
supertype descriptor pattern manager-provider


AGENDA




WATERFALL? BIG-UP FRONT?

Architecture!


WATERFALL? BIG-UP FRONT?


THE WATERFALL DENTIST


BOEHM’S LAW


AGILE. NO UP-FRONT?

Architecture?


BOEHM’S LAW. PER ITERATION


AGILE. SOME UP-FRONT

Just enough
architecting!

Frameworks?


HOFSTADTER’S LAW
It always takes longer than you expect, even when you take into account Hofstadter’s Law

MYFIRSTSURVEY


LIFE IS NEVER EASY …
Frameworks, like pizzas, come in only two sizes: too big and too small.

MYFIRSTSURVEY


General purpose frameworks
WHAT’S IT GONNA BE PUNK?
Enterprise Library, Spring.Net, Castle, NakedObjects,
Accelerated Delivery Framework (ADF), SubSonic

Single goaled frameworks – verticals Single goaled frameworks – architectural
Dependency injection: ObjectBuilder, Unity, Castle Windsor User interface: Silverlight, ASP.NET MVC, WPF, ASP.NET
Ajax, Spring MVC
Logging: Log4Net, Logging Block, Common.Logging
Process: UI Process Application Block, WF
Exception handling: Exception Handling Block
Domain: Entity Framework, Hibernate, NEO
Apect orientation: PostSharp, SetPoint
Search: Lucene.net, NLucene Data: Entity Framework, Hibernate, Castle ActiveRecord,
CSLA
Portals: DotNetNukeSpatial, Umbraco
Service s: WCF, WCF RIA


FRAMEWORKS - CODEPLEX


FRAMEWORKS – WWW.CSHARPOPENSOURCE.COM


FRAMEWORKS – MICROSOFT ENTERPRISE LIBRARY


FRAMEWORKS – PROJECT CASTLE


DON’T BELIEVE THE HYPE – IT’S A SQL


CONVINCING THE MANAGEMENT TO APPLY THE FRAMEWORK (25.5 %)


UNDERSTANDING THE FRAMEWORK (56.4 %)


CONVINCING OTHER DEVELOPERS TO USE THE FRAMEWORK (23.6 %)


TRAINING THE DEVELOPERS (20 %)


THE EYE OF THE TIGER


AGENDA




APPLYING FRAMEWORKS
My software never has bugs. It just develops random features

AGILE. SOME UP-FRONT

Just enough
architecting!

Frameworks? Just enough
re-architecting


SO GLAD YOU MADE IT! What if the author of our
favorite framework suddenly
What if we require stops developing it?
additional features that
aren’t covered by our
framework?

And what if the new version
of our framework is
implemented totally
different?
What if we decide that
another framework might
be better than the one
we’re using now?

What if the framework
contains bugs?

MORE THAN ANYTHING, DEPENDENCIES WILL KILL YOUR PROJECT


KENTUCKY FRIED ARCHITECTURE
A short story about framework developers and application developers

PIGS & CHICKENS

The framework The application
developer developer


KFC ARCHITECTURE – ENTITY FRAMEWORK


beta!
Here’s … beta !

LETTING THE LUNATICS RUN THE ASYLUM
I don’t care if it works on your machine! We are not shipping your machine!

HOT OR NOT?
Hot? From hot to not? Not?

Metro Expression Blend Entity Framework 2.0
HTML5 ASP.NET Ajax LINQ2SQL
LightSwitch REST LINQ2Entities
WCF RIA Services Unity Entity Data Model
Silverlight 4.0? BizTalk Dublin
ASP.NET MVC 3 Surface DSL’s
MEF Duet Silverlight 2.0
jQuery SketchFlow F#
NService Bus Azure Services ASP.NET
Entity Framework - Code First ADO.NET Data Services PopFly
ASP.NET Dynamic Data M
WPF Oslo
MGrammar


BE A F***ING GENIUS

Metro?

WTF? I just figured
out ASP.NET MVC


HERE’S JOHNNY! – ASP.NET MVC


NO STRINGS ATTACHED
It’s only in theory that practice and theory are the same

MYFIRSTSURVEY


CHANGING BASE CLASSES – – NHIBERNATE / LOG4NET


CHANGING BASE CLASSES – NHIBERNATE / LOG4NET


YES, YOUR FRAMEWORKS VERSION TOO
Programming is like sex.
One mistake and you have to support it for the rest of your life

IT AIN’T OVER TILL IT’S OVER


MISSING BASE CLASSES – WORKFLOW FOUNDATION 4.0


AGENDA




SOUND ARCHITECTURE
Architecture starts when you carefully put two bricks together. There it begins.

(SOFTWARE.ARCHITECTURE != LIST<FRAMEWORK>)

A SOFTWARE ARCHITECTURE


Pages
Presentation Android? UserControls
XAML? Panels
What to do? ASPX?

Use cases
Process Workflow
• Identify your architectural requirements Entities
(from EF)
• Set up a (layered) architecture Domain MVVM?
Services MVP?
• Identify layers and layer elements
Domain
Domain objects / Entities
MVWTF?
Factories / Repositories
• List the elements responsibilities Enums / Value objects / Smart references
Metadata?
• List the elements collaborations JSON?
• And only then map to frameworks Service gateways
Data / Services Service locators
• Create a thin “umbrella” of independence [Mapping]
EF?
responsible for managing dependencies LINQ?
Exact SAP BizTalk Java
Nhibernate?
Databases
Outside world Services / ESB


LAYER SUPERTYPE
From a developers point of view the user is a peripheral
that types when you issue a read request.

LAYER SUPERTYPE What’s a layer supertype Ollie?
Acts as a supertype for all types in its layer
All types inherit from the layer supertype

Well Stan, it’s characteristics are
Name expresses common behaviour
Forces common features on all inherited types
Ideal starting point for services
Initially the layer supertype is empty
Reserve layer supertype for future additions

60 HOW FRAMEWORKS CAN KILL YOUR AGILE PROJECTS Extension methods don’t (always) help, you know

LAYER SUPERTYPE – ASP.NET MVC


Pages
Presentation UserControls
Panels

Use cases
Process Workflow

Domain objects / Entities
Domain Factories / Repositories
Enums / Value objects / Smart references

Service gateways
[Mapping]

Databases


LAYER SUPERTYPE – USING A LAYER SUPERTYPE


LAYER SUPERTYPE – REASON ABOUT LAYER SUPERTYPES


LAYER SUPERTYPE – EXTENSION METHODS ON LAYER SUPERTYPES


AGENDA




DESCRIPTOR
Always code as if the guy who ends up maintaining your code
will be a violent psychopath who knows where you live.

I KNOW NOTHING. I’M FROM BARCELONA

What is the matter
Mister Fawlty?

The problem Manuel, is that
I want to use constants in my
application
But I want to define them in my
framework and extend them in my
application
Enumeration won’t do – there’s no
inheritance

DESCRIPTOR – THE PROBLEM (1)


DESCRIPTOR – THE PROBLEM (2)


ENUM?


STRING COLLECTION?


STRING COLLECTION


I KNOW NOTHING. I’M FROM BARCELONA

Descriptor
Defines a restricted but
application specific
extendible list of definitions

Useful when
Enums can not be inherited
Framework defines enumeration types that
need to be extended in application code
Define layer supertype using reflection
Pre-define frequently used instances


DESCRIPTOR PATTERN


DESCRIPTOR PATTERN - DEFINITION


DESCRIPTOR PATTERN – EXTENDED DEFINITION


DESCRIPTOR PATTERN – USE IN FRAMEWORK


DESCRIPTOR PATTERN – USE IN APPLICATION


MYFIRSTSURVEY


DESCRIPTOR PATTERN – USE IN ASP.NET MVC


AGENDA




DEPENDENCY INJECTION
XML is like violence. If it doesn’t solve your problems, you are not using enough of it.

A NEW DISEASE? What do you think it is?

Create true separation between definition
and implementation, so that the two can
vary independently and can be replaced
easily

So …
Single topic services
Looks like a typical case of dependency injection
Single or multiple implemenations need to
Call functionality without having to know be handled, which differs dependant on
the actual implementation context, like with Windows API, logging or
error handling
Implement replaceable services
Unit testing
Apply implementations in different contexts
Plug-in services at run-time

DIFFERENT VARIATIONS? Did you know that there
are different types of this
dependency injection?

Yeah, sure. There’s Arggh…
Constructor injection
Property (setter) injection
And even manual injection Who cares doc?

DEPENDENCY INJECTION – CONSTRUCTOR INJECTION


DEPENDENCY INJECTION – MANUAL INJECTION

c


DEPENDENCY INJECTION – WHAT TO PLUG IN


MANAGER – PROVIDER
"Teamwork is a lot of people doing what I say“ - Marketing executive, Citrix Corporation

MANAGER-PROVIDER PATTERN

Definition
Create a simple static facade
(manager) for a (set of) interfaced
implementations (providers)

In practice
Manager holds one or a collection of
providers
Provider implement a particular
interface
Manager has methods to call methods
from interface
At run-time, using dependency
injection, actual providers are injected


MANAGER – VALIDATIONMANAGER


INTERFACE


MANAGER – INITIALIZATION (USING DEPENDENCY INJECTION)


CONFIGURATION OF IMPLEMENTATION


MANAGER - EXECUTING METHODS


CLIENT – CALLING METHODS


MANAGER-PROVIDER PATTERN
Useful when
Generic services need to be called,
which may have different implementations
Manager prevents having to loop
through each of a list of providers
Flexibility to add or remove providers
without changing application code
Providers differ e.g. in development code,
test code or deployed code
Use for
Task Management
View Management
Binding and Persisting
Resource Management
State Management
Logging
Datasource interaction
Testing!


ARCHITECTURAL CHANGES IN AGILE?
Re-factoring or re-architecting?

Pages
Presentation UserControls
Panels
What to do?
Use cases
Process Workflow
• Identify your architectural requirements
• Set up a (layered) architecture
Domain
• Identify layers and layer elements Domain objects / Entities
Factories / Repositories
• List the elements responsibilities / Value objects / Smart references
Enums
• List the elements collaborations
• And only then map to frameworks Service gateways
• Create a thin “umbrella” of independence [Mapping]
responsible for managing dependencies
Databases


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