ABAP CodeRetreat 20.5.2017 Vienna - Refactoring

@foessleitnerj

Refactoring

… with ADT

@foessleitnerjRefactoring with ADT

“The process of changing a software system in such a way that it does not alter the external behaviour of the code, yet improves its internal structure.”

What is Refactoring?

Martin Fowler, Refactoring 1999

https://www.refactoring.com

@foessleitnerjRefactoring with ADT

ISBN: 978-0201485677

Refactoring, by Martin Fowler

@foessleitnerjRefactoring with ADT

Test Development

Refactoring

• Add a Test Make it work

Make it clean

Refactoring & TDD

@foessleitnerjRefactoring with ADT

TDD RefactoringRefactoring

?Refactoring

?Refactoring

Workflow of Refactoring

?Refactoring

@foessleitnerjRefactoring with ADT

Workflow of Refactoring

Just bad code!Litter-PickupRefactoring

?Refactoring

?Refactoring

TDD RefactoringRefactoring

@foessleitnerjRefactoring with ADT

Workflow of Refactoring

I don‘tunderstand

Litter-PickupRefactoring

ComprehensionRefactoring

?Refactoring

TDD RefactoringRefactoring

@foessleitnerjRefactoring with ADT

Workflow of Refactoring

We shouldhave done itthis way

Litter-PickupRefactoring

ComprehensionRefactoring

PreparatoryRefactoring

TDD RefactoringRefactoring

@foessleitnerjRefactoring with ADT

Code Smells „stinkt“ (© Robert C. Martin)

• Examples

• Duplicates

• Long methods

• Big classes

• Big case statements

• Bad names

• Misleading comments

• …

@foessleitnerjRefactoring with ADT

Example 1: Misleading comments

* get all fields of BUT000

SELECT PARTNER, NAME1 FROM BUT000 INTO …

* exit on error & FLAG <> ‘X‘

IF SY-SUBRC > 0 AND FLAG = ABAP_TRUE.

EXIT.

ENDIF.

@foessleitnerjRefactoring with ADT

Example 2: Method name

•What happens in the method• LR_DATE->ADD( 5 )

•Better• LR_DATE->ADDDAYSTO( 5 )

• LR_DATE->INCREASEBYDAYS( 5 )

@foessleitnerjRefactoring with ADT

https://www.refactoring.com

@foessleitnerjRefactoring with ADT

Code Quality

Clean Code

Profssionalism

Right Thing

Why Refactor?

@foessleitnerjRefactoring with ADT

Why Refactor?

Economy

@foessleitnerjRefactoring with ADT

“We are doing this, to be able to deliver more functionality more quickly.”

Martin Fowler, a pionier of the agile software development

Why Refactor?

@foessleitnerjRefactoring with ADT

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Thank you!https://twitter.com/domibiglsap

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