Clean Code III

Chandler, Oct. 18th, 2014

Software Craftsmanship

Desert Code Camp 2014.2

Theo Jungeblut• Engineering manager & lead by day

at AppDynamics in San Francisco

• Coder & software craftsman by night, first time dad and house builder

• Architects decoupled solutions & crafts maintainable code to last

• Worked in healthcare and factory automation, building mission critical applications, framework & platforms

• Degree in Software Engineeringand Network Communications

• Enjoys cycling, running and eating theo@designitright.net

www.designitright.net

We are hiring!http://www.appdynamics.com/ careers

and there are much more positions

Your feedback is important!

http://www.speakerrate.com/theoj

Where to get the Slides

http://www.slideshare.net/theojungeblut

Overview

• Why Clean Code?• The Power of Simplicity• Tools - Your Best Friend• From Names to Classes• The "Must Read"-Books• Summary• Q&A

Does writing Clean Code make us more efficient?

The only valid Measurement of Code Quality

What is Clean Code?

Clean Code is maintainable

Source code must be:• readable & well structured• extensible• testable

Software Engineering

&Software

Craftsmanship

The “Must Read”-Book(s)by Robert C Martin

A Handbook of Agile Software Craftsmanship

“Even bad code can function. But if code isn’t clean, it can bring a development organization to its knees.”

Code Maintainability *

Principles Patterns Containers

Why? How? What?

Extensibility Clean Code Tool reuse

* from: Mark Seemann’s “Dependency Injection in .NET” presentation Bay.NET 05/2011

Keep it simple, stupid(KISS)

KISS-Principle – “Keep It Simple Stupid”

http://blogs.smarter.com/blogs/Lego%20Brick.jpg

by Kelly Johnson

The Power of Simplicity

http://www.geekalerts.com/lego-iphone/

Graphic by Nathan Sawaya courtesy of brickartist.com

Graphic by Nathan Sawaya courtesy of brickartist.com

Chaos build from simplicity

Graphic by Nathan Sawaya courtesy of brickartist.com

Source Code Conventions

.NET Tools and their ImpactTool name Positive Impact Negative Impact

Resharper compiling ++++, learning +++

VS responsiveness --

FxCop code quality ++ compiling time -

StyleCop code consistency +++ compiling time -

StyleCop plugin for Resharper

compiling time +++ VS responsiveness --

Ghost Doc automated docs potentially worse doc

Spell Checker fewer spelling errors ++ performance --

Code Contracts testability, quality ++ compiling time --

Code Digger automated test ++ compiling time --

Resharper

Features:– Code Analysis – Quick Fixes– Code Templates – Code Generation– Code Cleanup– Many, many more…

“The single most impacting development addition to Visual Studio”

http://www.jetbrains.com/resharper/

FxCop / Static Code Analysis

Code Analysis:– Correctness– Library design– Internationalization and localization– Naming conventions– Performance– Security

http://msdn.microsoft.com/en-us/library/3z0aeatx.aspx

Style Cop with R# Integration

Code Consistency & Readability:– Automated check of C# coding standard– Enforceable at check-in with TFS check-in

Policy

– Full Integration in Resharper with Style Cop plugin:

– Code Analysis – Quick Fixes– Code Cleanup

http://submain.com/products/ghostdoc.aspx

• Save keystrokes and time• Simplify documenting your code• Benefit of the base class documentation• Source code and text spellcheck (Pro version)• API documentation creation (Pro version)

Ghost Doc

Spell Checker

http://visualstudiogallery.msdn.microsoft.com/7c8341f1-ebac-40c8-92c2-476db8d523ce/

• Spelll chicking for literals and comments in VS

http://msdn.microsoft.com/en-us/devlabs/dd491992

• Design-by-Contract programming• Improved testability• Static verification• API documentation integration with Sandcastle

• Pex automatically generates test suites with high code coverage.

• Moles allows to replace any .NET method with a delegate.

Flakes (Microsoft Pex & Moles)

http://research.microsoft.com/en-us/projects/pex/

Names Matter

• Meaningful Names• Intention Revealing Names• Use Pronounceable Names• Use Searchable Names• Avoid Encoding (Hungarian)• Don’t be cute• Pick One Word per Concept• Use Problem Domain Names

* Chapter extract: Robert C. Martin –” Clean Code”, Parson Education, Inc. 2008

Functions

• Small – Do One Thing• One Level of Abstraction• No or only few Arguments• Have No Side Effects• Prefer Exceptions to

Returning Error Codes• Don’t Repeat Yourself

* Chapter extract: Robert C. Martin –” Clean Code”, Parson Education, Inc. 2008

Comments

• Comments do not Make Up for Bad Code• Explain Yourself in Code• Clarification• Warning of Consequences• ToDo Comments• Javadocs in Public APIs

* Chapter extract: Robert C. Martin –” Clean Code”, Parson Education, Inc. 2008

Bad Comments

• Mumblings• Redundant Comments• Misleading Comments• Journal Comments• Noise Comments• Don’t use a Comment When you Use a

Method or a Variable• Commented-Out Code

* Chapter extract: Robert C. Martin –” Clean Code”, Parson Education, Inc. 2008

The Purpose of Formatting

• Team Rules – Consistency is King• Vertical Openness Between Concepts• Vertical Distance• Horizontal Alignment• Indentation• Write Journey Style Code

Resharper & StyleCop – “Code Cleanup”

* Kind of Chapter extract: Robert C. Martin –” Clean Code”, Parson Education, Inc. 2008

Classes

• Class Organization • Encapsulation• Classes Should be Small• The Single Responsibility Principle• Cohesion• Organize for Change• Insolating from Change

* Kind of Chapter extract: Robert C. Martin –” Clean Code”, Parson Education, Inc. 2008

The “Must Read”-Book(s)by Robert C Martin

A Handbook of Agile Software Craftsmanship

“Even bad code can function. But if code isn’t clean, it can bring a development organization to its knees.”

The “Must Read”-Book(s)by Krzysztof Cwalina, Brad Abrams

Framework Design Guidelines

“teaches developers the best practices for designing reusable libraries for the Microsoft .NET Framework.”

Summary Clean Code

Maintainability is achieved through:

• Readability (Coding Guidelines)

• Simplification and Specialization (KISS, SoC, SRP, OCP, )

• Decoupling (LSP, DIP, IHP, Contracts, LoD, CoP, IoC or SOA)

• Avoiding Code Bloat (DRY, YAGNI)

• Quality through Testability (all of them!)

Downloads, Feedback & Comments:

Q & A

Graphic by Nathan Sawaya courtesy of brickartist.com

theo@designitright.netwww.designitright.net www.speakerrate.com/theoj

References… http://clean-code-developer.comhttp://michael.hoennig.de/2009/08/08/clean-code-developer-ccd/http://butunclebob.com/ArticleS.UncleBob.PrinciplesOfOodhttp://www.manning.com/seemann/http://en.wikipedia.org/wiki/Keep_it_simple_stupidhttp://picocontainer.org/patterns.htmlhttp://en.wikipedia.org/wiki/Separation_of_concernshttp://en.wikipedia.org/wiki/Single_responsibility_principlehttp://en.wikipedia.org/wiki/Information_hidinghttp://en.wikipedia.org/wiki/Liskov_substitution_principlehttp://en.wikipedia.org/wiki/Dependency_inversion_principlehttp://en.wikipedia.org/wiki/Open/closed_principlehttp://en.wikipedia.org/wiki/Law_Of_Demeterhttp://en.wikipedia.org/wiki/Don't_repeat_yourselfhttp://en.wikipedia.org/wiki/You_ain't_gonna_need_ithttp://en.wikipedia.org/wiki/Component-oriented_programminghttp://en.wikipedia.org/wiki/Service-oriented_architecturehttp://www.martinfowler.com/articles/injection.htmlhttp://www.codeproject.com/KB/aspnet/IOCDI.aspxhttp://msdn.microsoft.com/en-us/magazine/cc163739.aspxhttp://msdn.microsoft.com/en-us/library/ff650320.aspxhttp://msdn.microsoft.com/en-us/library/aa973811.aspxhttp://msdn.microsoft.com/en-us/library/ff647976.aspxhttp://msdn.microsoft.com/en-us/library/cc707845.aspxhttp://msdn.microsoft.com/en-us/library/bb833022.aspxhttp://unity.codeplex.com/http://www.idesign.net/idesign/DesktopDefault.aspx?tabindex=5&tabid=11

… more ReferencesResharperhttp://www.jetbrains.com/resharper/

FxCop / Code Analysis http://msdn.microsoft.com/en-us/library/bb429476(VS.80).aspxhttp://blogs.msdn.com/b/codeanalysis/http://www.binarycoder.net/fxcop/index.html

Code Contractshttp://msdn.microsoft.com/en-us/devlabs/dd491992http://research.microsoft.com/en-us/projects/contracts/

Fakes (Previous Moles & Pex)http://www.richonsoftware.com/post/2012/04/20/Comparing-Microsoft -Moles-in-Visual-Studio-2010-to-Microsoft-Fakes-in-Visual-Studio-11.aspxhttp://research.microsoft.com/en-us/projects/pex/

StyleCophttp://stylecop.codeplex.com/

Ghostdoc http://submain.com/products/ghostdoc.aspx

Spellcheckerhttp://visualstudiogallery.msdn.microsoft.com/7c8341f1-ebac-40c8-92c2-476db8d523ce//

Lego (trademarked in capitals as LEGO)

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