your code is collapsing- how refactoring can save your ass 2012 03-01 - confoo

Your Code is CollapsingHow Refactoring Can Save Your

Thursday, 1 March, 12

DISCLAIMER

Refactoring can generate endless discussions. What we will share

today are original thoughts on the topic, in order to provide ideas to address your own situation (every

situation is different)


Lack of Refactoring


GrandPerspectiveThursday, 1 March, 12

DbVisualizerThursday, 1 March, 12

StatSVN

Developers modify code much more often than they write new code


Our brain’s processing power is extremely overrated


Lack of Refactoring causes:

Slower DeliveryMore DefectsLower Morale

It’s a vicious circle!


“If it ain’t broke, don’t fix it”


When reusing the source code ends up costing more than

starting from scratchThursday, 1 March, 12

You say: “technical debt”

I ask: “credit history?”


Solution

The solution involves change management techniques. It requires education, awareness, incentives, making metrics visible, reports and alerts automatically generated (CI). Different levels of awareness will cause frustrations.You will often need external help (coaching.).


Solution

1. NEW CODE BASE: continuous refactoring (and automated tests). Ideally, TDD (Red, Green, Refactor)

2. EXISTING CODE BASE: cost-benefit analysis (how long is the product to be supported?)


Raising Awareness


Explain refactoring to non-programmers with

writing recipes


How much time does it take to spot the error?


Preheat oven to 425F and place rack in center.Wash the cherries, remove stems and pits.In blender, process flour, salt, eggs, sugar,and vanilla extract until completely smooth.Let batter rest.In large 9-inch nonstick skillet melt butter over medium heat.Add cherries, and cook for 3 minutes. Add the remaining sugar and cook for 2 more minutes.Pour the batter over the cherries and bake for about 20 minutes or until the clafoutis is puffed, set, and golden brown around the edges.

1/2 cup all purpose flour1/4 teaspoon

salt2 large eggs2 tbsp sugar3/4 cup milk1/2 teaspoon

vanilla extract

1 lb fresh cherries

1 tbsp butter2 tbsp sugar


Solution


Preheat oven to 425F and place rack in center.Wash the cherries, remove stems and pits.In blender, process flour, salt, eggs, sugar, milk,and vanilla extract until completely smooth.Let batter rest.In large 9-inch nonstick skillet melt butter over medium heat.Add cherries, and cook for 3 minutes. Add the remaining sugar and cook for 2 more minutes.Pour the batter over the cherries and bake for about 20 minutes or until the clafoutis is puffed, set, and golden brown around the edges.

1/2 cup all purpose flour1/4 teaspoon

salt2 large eggs2 tbsp sugar3/4 cup milk1/2 teaspoon

vanilla extract

1 lb fresh cherries

1 tbsp butter2 tbsp sugar


Let’s Refactor


Preheat oven to 425F and place rack in center.Wash the cherries, remove stems and pits.

In blender, process flour, salt, eggs, sugar, milk,and vanilla extract until completely smooth.

Let batter rest.

In large 9-inch nonstick skillet melt butter over medium heat.

Add cherries, and cook for 3 minutes. Add the remaining sugar and cook for 2 more minutes.Pour the batter over the cherries and bake for about 20 minutes or until the clafoutis is puffed, set, and golden brown around the edges.

1 lb fresh cherries

1/2 cup flour1/4 teaspoon salt

2 large eggs2 tbsp sugar3/4 cup milk1/2 teaspoonvanilla extract

1 tbsp butter

2 tbsp sugar


And now?


Preheat oven to 425F and place rack in center.Wash the cherries, remove stems and pits.

In blender, process flour, salt, eggs, sugar,and vanilla extract until completely smooth.

Let batter rest.

In large 9-inch nonstick skillet melt butter over medium heat.

Add cherries, and cook for 3 minutes. Add the remaining sugar and cook for 2 more minutes.Pour the batter over the cherries and bake for about 20 minutes or until the clafoutis is puffed, set, and golden brown around the edges.

1 lb fresh cherries

1/2 cup flour1/4 teaspoon salt

2 large eggs2 tbsp sugar3/4 cup milk1/2 teaspoonvanilla extract

1 tbsp butter

2 tbsp sugar


Source code is invisible (by default)

Problems with source code are even less visible


Junior developers don’t see the point. Senior developers

don’t care.. Project Managers, well...


MAKE IT VISIBLE!

Even Better:

MAKE IT STINK!


Code Smellshttp://www.codinghorror.com/blog/2006/05/code-smells.html


http://www.codinghorror.com/blog/2006/05/code-smells.html

http://www.codinghorror.com/blog/2006/05/code-smells.html

Ideas

1. Sonar (SonarSource.org) can display, for each build: code coverage, complexity metrics, rules compliance...2. Use in conjunction with Continuous Integration (Jenkins). Configure to alert when non compliant3. Name Code Quality Managers4. Regular Retrospectives to discuss rules


SonarThursday, 1 March, 12

Ideas5. Provide realistic estimates which include time to refactor (include in your definition of DONE)6. Multiple little refactorings are better than large ones7. Rule of thumb: dedicate 10% of your time to refactor (before each commit)8. Metrics: watch TRENDs, NOT absolute numbers


Books

• Refactoring by Martin Fowler (1999)

• Refactoring to Patterns by Joshua Kerievsky (2004)

• Code Complete 2 by Steve McConnell (2004)

• Clean Code by Robert C. Martin (2008)


@ogourment

[email protected]


mailto:[email protected]

mailto:[email protected]

your code is collapsing- how refactoring can save your ass 2012 03-01 - confoo

Technology

fresh cherries

tbsp butterin large

tbsp sugarpour

theremaining sugar

the1 tbsp butter

cup milklet batter rest

large eggsand vanilla

teaspoonvanilla extract