Agile and Frameworks

HOW FRAMEWORKS CAN KILL YOUR AGILE PROJECTSSander Hoogendoorn | Principal Technology Officer, Global Agile Thought Leader | Capgeminiwww.sanderhoogendoorn.com | [email protected] | @aahoogendoorn

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

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

� [email protected]

� @aahoogendoorn @ditisagile




AGENDA

An short storyabout frameworks

How frameworks canget you in trouble

Software architectureversus frameworks

The layersupertype

Introducing thedescriptor pattern

The manager-provider


AGENDA




The layersupertype




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 enougharchitecting!

Frameworks?

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 %)


CONVINCING OTHER DEVELOPERS TO USE THE FRAMEWORK (23.6 %)


TRAINING THE DEVELOPERS (20 %)


THE EYE OF THE TIGER


AGENDA




The layersupertype



My software never has bugs. It just develops random features

APPLYING FRAMEWORKS


AGILE. SOME UP-FRONT

Just enougharchitecting!

Frameworks? Just enoughre-architecting


SO GLAD YOU MADE IT!

What if we requireadditional features thataren’t covered by our

framework?

What if we decide thatanother framework mightbe better than the onewe’re using now?

What if the author of ourfavorite framework suddenly

stops developing it?

What if the framework contains bugs?

And what if the new versionof 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


PIGS & CHICKENS

The applicationdeveloper

The frameworkdeveloper


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’sHere’sHere’sHere’s … … … … betabetabetabeta!!!!


HOT OR NOT?

Hot? From hot to not? Not?

Metro

HTML5

LightSwitch

WCF RIA Services

Silverlight 4.0?

ASP.NET MVC 3

MEF

jQuery

NService Bus

Entity Framework - Code First

Expression Blend

ASP.NET Ajax

REST

Unity

BizTalk

Surface

Duet

SketchFlow

Azure Services

ADO.NET Data Services

ASP.NET Dynamic Data

WPF

Entity Framework 2.0

LINQ2SQL

LINQ2Entities

Entity Data Model

Dublin

DSL’s

Silverlight 2.0

F#

ASP.NET

PopFly

M

Oslo

MGrammar


BE A F***ING GENIUS

Metro?

WTF? I just figured out ASP.NET MVC


HERE’S JOHNNY! – ASP.NET MVC


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


MISSING BASE CLASSES – WORKFLOW FOUNDATION 4.0


AGENDA




The layersupertype



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

PagesUserControls

Panels

Use casesWorkflow

Domain objects / EntitiesFactories / Repositories

Enums / Value objects / Smart references

Service gatewaysService locators

[Mapping]

DatabasesServices / ESB

Exact SAP BizTalk Java

Android?XAML?ASPX?

Entities(from EF)

DomainServices

Metadata?JSON?

EF?LINQ?

Nhibernate?

MVVM?MVP?

MVWTF?

What to do?

• Identify your architectural requirements

• Set up a (layered) architecture

• Identify layers and layer elements

• List the elements responsibilities

• List the elements collaborations

• And only then map to frameworks

• Create a thin “umbrella” of independence

responsible for managing dependencies

From a developers 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


LAYER SUPERTYPE – ASP.NET MVC


Presentation

Process

Domain

Data / Services

Outside world

PagesUserControls

Panels

Use casesWorkflow




[Mapping]




LAYER SUPERTYPE – USING A LAYER SUPERTYPE


LAYER SUPERTYPE – REASON ABOUT LAYER SUPERTYPES


LAYER SUPERTYPE – EXTENSION METHODS ON LAYER SUPERTYPES


AGENDA




The layersupertype



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 matterMister Fawlty?

The problem Manuel, is that

� I want to use constants in myapplication

� But I want to define them in myframework and extend them in myapplication

� Enumeration won’t do – there’s noinheritance


DESCRIPTOR – THE PROBLEM (1)


DESCRIPTOR – THE PROBLEM (2)


ENUM?


STRING COLLECTION?


STRING COLLECTION


I KNOW NOTHING. I’M FROM BARCELONA

Descriptor

Defines a restricted butapplication specificextendible list of definitions

Useful when

� Enums can not be inherited

� Framework defines enumeration types thatneed 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


DESCRIPTOR PATTERN – USE IN ASP.NET MVC


AGENDA




The layersupertype



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

� Call functionality without having to knowthe 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 oncontext, like with Windows API, logging orerror handling

� Unit testing


DIFFERENT VARIATIONS? Did you know that thereare 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

"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


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!

Re-factoring or re-architecting?

ARCHITECTURAL CHANGES IN AGILE?


Presentation

Process

Domain

Data / Services

Outside world

PagesUserControls

Panels

Use casesWorkflow




[Mapping]



What to do?

• Identify your architectural requirements

• Set up a (layered) architecture

• Identify layers and layer elements

• List the elements responsibilities

• List the elements collaborations

• And only then map to frameworks

• Create a thin “umbrella” of independence

responsible for managing dependencies

[email protected] | [email protected] | @aahoogendoorn | @ditisagilewww.sanderhoogendoorn.com | www.ditisagile.nl | www.smartusecase.com | www.accelerateddeliveryplatform.com

REFERENCES AND QUESTIONS