Software Craftsmanship

© 2004 Capgemini - All rights reserved

Professional Software Craftsmanship

2011-10-13

Andreas Enbohm

Twitter: enbohm

© 2009 Capgemini - All rights reserved12 april 2023

The Clean Coder by @unclebobmartin

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© 2009 Capgemini - All rights reserved12 april 2023Sida 3

Craftsmanship

”A software craftman is a experienced professional who quickly, but without rushing, provides resonable estimates and meets

commitments. A person which brings to mind skill, competence and quality. A craftman knows when to say no, but tries hard to

say yes. [Software] Craftmanship is the mindset held by craftsmen.”


Professionalism

Professional vs. Nonprofessional

It’s all about taking responsibility!

First, do no harm!- you must NOT create bugs! - but thats virtually impossible

All means to create bug free code- QA should find nothing- if they do, learn from it to prevent it from happend again

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Professionalism

How do you know your code works?

Easy;- test- test again- test it up- test it down- test ALL of it- automated test suites- test upside down- test inside out- test left to right- TEST DRIVE IT!

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Professionalism

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Boy Scout Ruleor

Merciless Refactoring


Professionalism

Work ethics- 40/20 h week- read blogs, tweets, conferences, try languages…

Know your field!- Nassi-Schneiderman charts- Mealy and Moore state machines- Quicksort without looking it up- Parnas tables- Tramp data- Jackson Structured Programming

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Professionalism

Practice!- Code Katas

Mentoring!

Know your domain!- no need to be expert- unprofessional to ’just code’

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Saying No

”Do; or do not. There is no try”

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Saying No

Never say ”I’ll try” - others will interpret as ”Yes”- avoid (unprofessional) pleasant conversation - but what would the world be if we didn’t try things?

Try == to apply extra effort- if there is extra effort, why hasn’t the team applied it before?- have you/team been holding effort in reserve?- by trying, the previous plans you made are insufficient- what behavior will you change by ’trying’?

Cut the scope! Negotiate – but never try!

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Handling Pressure

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Handling Pressure

Overtime if, and only if, 1) you can personally afford it 2) it is short term 3) you boss has a fallback plan

3) is a deal breaker- if your boss don’t have a backup plan, you should not agree on overtime

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Handling Pressure

Stayin clean- dirty code ALWAYS means slow!- a professional NEVER tolerate messes

Trust your disciplines!- follow them at ALL times. Best way to avoid crisis- practive them even harder (more tests, smaller methods..)

You won’t go faster without test

You won’t go faster without refactoring

You won’t go faster without running full regressions test

But it’s tempting for a novice…

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Handling Pressure

Commitments- do not accept unrealistic commitments (never ’try’)- commit ONLY when you are certain

Don’t panic- eat, sleep well- pair programming / ask for help

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Time Estimates

Affinity Estimation

Wideband Delphi

Flying Fingers

Planning Poker

PERT- a way to convert estimates to probability distributions suitable for managers

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Time Estimates

Program Evaluation and Review Technique- US Navy’s Polaris Submarine project (1957)

Three number for each task- Optimistic (wildly)- Normal- Pessimistic (wildly)

µ = (O + 4N + P) / 6, where µ is expected duration (’väntevärde’)

σ = (P – O) / 6, where σ is the standard deviation

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PERT

Task Optimistic Normal Pessimistic µ σ

Task 1 1 3 12 4.2 1.8

Task 2 1 1.5 14 3.5 2.2

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Clean Coder

Questions?

http://slideshare.net/enbohm

http://codekata.pragprog.com/

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Software Craftsmanship

Technology

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