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

HOW TO AVOID GETTING KILLED


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 UGLYDependencies

� 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 enumerationtypes that need to be extended in application code

� Define layer supertype usingreflection

� 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 implemenationsneed to be handled, which differsdependant on context, like withWindows API, logging or errorhandling

� 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 injectionWho 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 UGLYDependencies

� 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

[email protected]

www.sanderhoogendoorn.com | www.smartusecase.com

Twitter: @aahoogendoorn

REFERENCES AND QUESTIONS

20101109 (tech ed) how frameworks kill projects

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