Post on 09-Aug-2020
Agile Software Design Urs Enzler – bbv Software Services AG
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Welcome Change
Small Increments
Always Running
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keep change local
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Make change local
Keep change local
What you gain
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Make Change Local
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DRY – don’t repeat yourself change in a single place
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public void DoMagic() { this.dependency.DelegateMagic( “magic”, 42) if (42 == i) { // … } }
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if (instance.Attribute) { } else { } switch (instance.Attribute) { case … }
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Web
Application
Windows
Application
Server
Address Address
Address
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Single Responsibility Give everything only one reason to change
A
B C
D
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Modules – make boundaries explicit separate physically and temporally
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Inversion of control manage construction, lifetime, configuration
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Loose Coupling – High Cohesion manage needed knowledge
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Problem! Visualize
Problem
too! Log
Broker
Publisher Subscriber
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Separate Cross-Cutting Concerns
public void DoMagic() { logger.Info(“starting magic!”); // … logger.Trace(“were’re here.”); // … logger.Debug(“magic achieved”); }
public void DoMagic() { logger.LogStartOfMagic(); } public static class LogExtensions { public static void LogStartOfMagic( this Ilogger logger) { logger.Info(“starting magic”) } }
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Namespaces Arrange Code per Feature
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Façade
Communication
Logic
UI
Business Logic
Data Access
Client
Server
Feature
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Namespace per Feature
• MyCompany • MyProject
• Feature1 • Feature2
• Grouping1 • Grouping2
• Feature3 • Feature4
• Grouping1 • DetailStuff
• Grouping2
Keep Change Local
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Unit Tests class boundary
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Acceptance Tests feature boundary
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𝒃𝒊𝒈 𝒔𝒚𝒔𝒕𝒆𝒎 = 𝒔𝒎𝒂𝒍𝒍 𝒔𝒚𝒔𝒕𝒆𝒎
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What You Gain
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evolving architecture
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always validated by
working code
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ask you this:
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how easily can it
be removed
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Urs Enzler urs.enzler@bbv.ch
OSS lead: Appccelerate
blog: www.planetgeek.ch
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twitter: @ursenzler
user group: www.dotnet-zentral.ch