Agile Software Architecture

© AgiliX Agile Development Consulting

Agile Software Architecture

Cesario Ramos


Code focussedDo what is important nowEvolves during the projectDefers Implementation

Documentation focussedDocumentation focussed

Do what is important in Do what is important in the long termthe long term

Defined upfrontDefined upfront

Includes ImplementationIncludes Implementation

Agile Agile ArchitectureArchitecture

Classic Classic ArchitectureArchitecture


Why agile software Why agile software architecture?architecture?


Deliver FastIncrease ROI.Early validation of your business case.Give customers what they want when they want it.


Defer CommitmentReduce risk.Decide based on most possible knowledge.

Keep yours and the customers options open.


Eliminate WasteSupport something that does not add value now.Have the architecture slow you down


Be the simplest solution to support the current Be the simplest solution to support the current functionality.functionality.

Change without increasing risk or waste.Change without increasing risk or waste.

Change economically.Change economically.

Change without making the software worse.Change without making the software worse.

Evolve in early and refine later iterations.Evolve in early and refine later iterations.

so we need architecture to...


Comparing with Comparing with engineeringengineering


Based on concrete analysis using physics and mathematics.Based on things you know and change slowly.Plan, Do, Review.

Plan the work, work the plan


RequirementsDesignCodingTestingRelease

AnalysisAnalysis

DesignDesign

ConstructionConstruction

InspectionInspection

ReleaseRelease

Software Software DevelopmentDevelopment

Civil Civil EngineeringEngineering

Coding is N

OT Constr

uction

Coding is N

OT Constr

uction


When do we test our When do we test our requirements?requirements?

When do we test our When do we test our design?design?

What if we overdevelop What if we overdevelop it? it?

How do you handle How do you handle changes?changes?

and then....

RequirementsRequirements

Architecture and DesignArchitecture and Design

CodingCoding

TestingTesting

ReleaseRelease


How to create agile software How to create agile software architecture?architecture?


High level steps.

Establish vision and high level requirements.

Perform Lightweight domain analysis.

Work on architectural components only when actually needed.

Consider ROI in the decision making process

Evolve the architecture during the project

Do not let quality decay.

Refactor to the Open Closed.

Validate and adapt.


Lean architecture using DCI

What the system ISCaptures what is stableThe domain classes

What the system DOESUser stories.Business objects.


Open Closed Principle

A module should be open for extension and closed for modification


Refactoring as Fowler proposed

Improving the design of existing code.

Refactoring to be Open Closed.

For handling future requirements.

Refactoring

Provides Value byProvides Value by

Reducing RiskReducing Risk

Reducing WasteReducing Waste


Separation Of Concerns

Low CouplingMinimal dependenciesMinimal side effects

High CohesionSingle responsibilityOne reason to change


Tests Drive Design

Forces you to look at your public API.Forces you to think about cohesion.Forces you to think about coupling.Forces you to not produce redundancies.


Test Driven Development

Documents your intentInvestigates the nature of the code you are developing Report on progress


Summary

Agile Architecture helps you reduce risk and waste.OO/XP principles and practices make evolving architecture possible.Particular approach depends upon knowledge of domain, technology and project size.


Agile Software Architecture

Cesario Ramos

Agile Software Architecture

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