20101109 (tech ed) how frameworks kill projects

And patterns to help you avoid getting killed
Sander Hoogendoorn | Principal Technology Officer | Capgemini | @aahoogendoorn
ARC203 - HOW FRAMEWORKS CAN KILL YOUR PROJECTS

2HOW FRAMEWORKS CAN KILL YOUR PROJECTS
©2010 Capgemini. All Rights Reserved
Capgemini
Principal technology officer
Global agile thought leader
Chief architect Accelerated Delivery Platform (ADP)
Other
Microsoft Partner Advisory Council .NET
Author books and articles in international
magazines
Appreciated speaker at international conferences
Columns in several magazines
Editorial boards
Web
www.sanderhoogendoorn.com
www.smartusecase.com
Twitter: @aahoogendoorn
SANDER HOOGENDOORN

ARC203 – How frameworks can kill your
projects
Tuesday 12:00
Hall 3.2 Interactive 2
ARC202 - How frameworks can kill your
projects
Wednesday 13:20
Hall 7.1b London 2
ARC203 – How frameworks can kill your
projects (repeat)
Thursday 10:30
Hall 3.2 Interactive 6
ARC205 – How smart use cases drive web
development
Friday 10:30
Hall 7.3 Berlin 1
SANDER HOOGENDOORN – TECHED 2010 SESSIONS

AGENDA
An short story
about frameworks
How frameworks can
get you in trouble
Software architecture
versus frameworks
The layer
supertype
Introducing the
descriptor pattern
The
manager-provider

AGENDA
An short story
about frameworks
How frameworks can
get you in trouble
versus frameworks
The layer
supertype
Introducing the
descriptor pattern
The
manager-provider

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

MYFIRSTSURVEY

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

MYFIRSTSURVEY

WHAT’S IT GONNA BE PUNK?
General purpose frameworks
Enterprise Library, Spring.Net, Castle, NakedObjects,
Accelerated Delivery Framework (ADF), SubSonic
Single goaled frameworks – verticals
Dependency injection: ObjectBuilder, Unity, Castle
Windsor
Logging: Log4Net, Logging Block, Common.Logging
Exception handling: Exception Handling Block
Apect orientation: PostSharp, SetPoint
Search: Lucene.net, NLucene
Portals: DotNetNukeSpatial, Umbraco
Single goaled frameworks – architectural
User interface: Silverlight, ASP.NET MVC, WPF, ASP.NET
Ajax, Spring MVC
Process: UI Process Application Block, WF
Domain: Entity Framework, Hibernate, NEO
Data: Entity Framework, Hibernate, Castle ActiveRecord,
CSLA
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
An short story
about frameworks
How frameworks can
get you in trouble
versus frameworks
The layer
supertype
Introducing the
descriptor pattern
The
manager-provider

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

SO GLAD YOU MADE IT!
What if we require
additional features that
aren’t covered by our
framework?
What if we decide that
another framework might
be better than the one
we’re using now?
What if the author of our
favorite framework suddenly
stops developing it?
What if the framework
contains bugs?
And what if the new version
of our framework is
implemented totally
different?

MORE THAN ANYTHING, DEPENDENCIES WILL KILL YOUR PROJECT

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

THE CUSTOMER IS NOT ALWAYS RIGHT

PIGS & CHICKENS
The application
developer
The framework
developer

KFC ARCHITECTURE – ENTITY FRAMEWORK

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

ON THE WRONG TRACK

HOT OR NOT?
Hot? From hot to not? Not?
HTML5
LightSwitch
WCF RIA Services
Silverlight 4.0
ASP.NET MVC 2 (3?)
ASP.NET Dynamic Data
ADO.NET Data Services
MEF
Azure Services
jQuery
NService Bus
Oslo
M
MGrammar
Expression Blend
ASP.NET Ajax
REST
Dublin
BizTalk
Surface
Duet
SketchFlow
Entity Framework 2.0
LINQ2SQL
LINQ2Entities
Entity Data Model
WPF
Unity
DSL’s
Silverlight 2.0
F#
ASP.NET
PopFly

HERE’S JOHNNY! – ASP.NET MVC

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

MYFIRSTSURVEY

CHANGING BASE CLASSES – – NHIBERNATE / LOG4NET

CHANGING BASE CLASSES – NHIBERNATE / LOG4NET

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

IT AIN’T OVER TILL IT’S OVER

MISSING BASE CLASSES – WORKFLOW FOUNDATION 4.0

AGENDA
An short story
about frameworks
How frameworks can
get you in trouble
versus frameworks
The layer
supertype
Introducing the
descriptor pattern
The
manager-provider

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

(SOFTWARE.ARCHITECTURE != LIST<FRAMEWORK>)

A SOFTWARE ARCHITECTURE

Presentation
Process
Domain
Data / Services
Outside world
Pages
UserControls
Panels
Use cases
Workflow
Domain objects / Entities
Factories / Repositories
Enums / Value objects / Smart references
[Mapping]
Service gateways
Service locators
[Mapping]
Databases
Services / ESB
Exact SAP BizTalk Java
Silverlight
XAML
Entities
(from EF)
Domain
Services
Metadata
Entity Framework
LINQ
Nhibernate?
MVVM?
MVP?

THE GOOD, THE BAD AND THE UGLY
Dependencies
Using frameworks is simply good, gringo
However, being dependant on third parties
can put your project at risk
How stable are the frameworks you use?
How stable is the framework vendor?
Minimize dependencies
Map frameworks to your software architecture,
not vice versa
Define your own layer supertypes
Wrap framework functionality
Apply manager-provider pattern
Implement extension methods if all fails

AGENDA
An short story
about frameworks
How frameworks can
get you in trouble
versus frameworks
The layer
supertype
Introducing the
descriptor pattern
The
manager-provider

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

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
Extension methods don’t (always) help, you know

LAYER SUPERTYPE – ASP.NET MVC

Presentation
Process
Domain
Data / Services
Outside world
Pages
UserControls
Panels
Use cases
Workflow
Domain objects / Entities
Factories / Repositories
Enums / Value objects / Smart references
[Mapping]
Service gateways
Service locators
[Mapping]
Databases
Services / ESB
Exact SAP BizTalk Java

LAYER SUPERTYPE – USING A LAYER SUPERTYPE

LAYER SUPERTYPE – DEFINE SERVICES ON LAYER SUPERTYPES

LAYER SUPERTYPE – EXTENSION METHODS ON LAYER SUPERTYPES

AGENDA
An short story
about frameworks
How frameworks can
get you in trouble
versus frameworks
The layer
supertype
Introducing the
descriptor pattern
The
manager-provider

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

I KNOW NOTHING. I’M FROM BARCELONA
What is the matter
Mister Fawlty?
The problem Manual, 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
An short story
about frameworks
How frameworks can
get you in trouble
versus frameworks
The layer
supertype
Introducing the
descriptor pattern
The
manager-provider

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

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

DIFFERENT VARIATIONS? Did you know that there
are different types of this
dependency injection?
Arggh…
Yeah, sure. There’s
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
Yes, XML will hurt you too!

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

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-PROVIDER PATTERN

MANAGER – VALIDATIONMANAGER

INTERFACE

MANAGER – INITIALIZATION (USING DEPENDENCY INJECTION)

CONFIGURATION OF IMPLEMENTATION

MANAGER - EXECUTING METHODS

CLIENT – CALLING METHODS

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!
MANAGER-PROVIDER PATTERN

THE GOOD, THE BAD AND THE UGLY
Dependencies
Using frameworks is simply good, gringo
However, being dependant on third parties
can put your project at risk
How stable are the frameworks you use?
How stable is the framework vendor?
Minimize dependencies
Map frameworks to your software architecture,
not vice versa
Define your own layer supertypes
Wrap framework functionality
Apply manager-provider pattern
Implement extension methods if all fails

www.accelerateddeliveryplatform.com
WWW.SMARTUSECASE.COM

sander.hoogendoorn@capgemini.com
www.sanderhoogendoorn.com | www.smartusecase.com
Twitter: @aahoogendoorn
REFERENCES AND QUESTIONS

20101109 (tech ed) how frameworks kill projects

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