refactoring

AS – Global Business Services

Brazilian Java AS Competency 12/12/08 © 2007 IBM Corporation

Refactoring

For ProgrammersCamilo Lopes


© 2007 IBM Corporation2 Brazilian Java AS Competency 12/12/08

Topics to be addressed Objective Why Refactoring? What is Refactoring ? Advantage When Refactoring Tools Results Example Java Questions



Objective

Assist in the development of system Object Oriented implements in the Java language that have fall reusability of code, maintaining hard and the add or adequacy of news requirement sue a lot of work of engineer Software, programmer, Analyst System, points that can generate big cost the project.



Time x Spent

Picture 1 believe that about 50% of time of an engineer Software is spent with task of maintaining and comprehension of code.Fonte: Maia (2004)

TimeSpent



Cost x Spent

Picture 2 The long of last three decade more of 60% of cost of development of Software of enterprise was spent with

CostSpent



Why Refactoring?

Refactoring help the become the code more legible and solve problem of bad code write



Definition Refactoring

Refactoring is the process of re-structure the system without change your functionality (Fowler,2004).



Motive to use Refactoring

Improve the project Software

Have a Software easier of comprehension the level code

Programmer faster



Advantage

The technical of refactoring can be applicate in the development and maintaining of Software;

Refactoring possibility the add of new functionality of mode easy averting the re-structure of code;

With the use of refactoring spent less time possible in maintaining the level code, improve the legibility and structure the code.



Tools

Xrefactoring: the languages compatible are C and Java this tools possibility the generation of documentation on format HTML;

RefactorIT: is a tools to refactoring that can be integrate in several IDEs.

Jfactor: is a tools that permit the application automatic of refactoring the program in Java.



When Refactoring ?

Code duplicate;

Method long;

Comments superfluous;

Command switch



Results

Easy in the process of maintaining and development of Software;

Can be applicate the any language Oriented Object;

Become the Software flexible to add of new functionality without re-structure of code;

Maintain the behavior of Software;



Example – Substitute a number literal by constant symbolic

Are numbers with value special in system;

Sometimes are use in more of a place;

To make the reading and comprehension

double energiaPotencial(double massa, double altura{

return massa * 9.81 * altura;} // code do not refactoring



Code Factored

static final double CONSTANTE_GRAVITACIONAL = 9.81;double energiaPotencial(double massa, double altura){ return massa * CONSTANTE_GRAVITACIONAL * altura;}

MECHANICSdeclare a constant and attribute a value to number literal;find where this number appear;see if the change can be to do, case positive change the number by constant;compile and test.



Questions?!

Thanks! http://camilolopes.wordpress.com

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