Feeds

Prefactoring

Getting it right first time

  • alert
  • submit to reddit

Providing a secure and efficient Helpdesk

PrefactoringBook review The title of this book should have been "Pre-refactoring", and for a suitable subtitle, "Getting It Right First Time" would have been a bit more informative than "Extreme Abstraction, Extreme Separation, Extreme Readability", which is a bit extreme on the extremes.

Refactoring, for those unfamiliar with the phrase, was coined by Martin Fowler in his influential book of the same name. It describes the process of improving the structure of the code without necessarily changing the functionality. Typically, this means rewriting code, reorganising classes, and redesigning software without breaking any applications that use the code. Think of it as an under the covers exercise that is invisible to consumers of an API or class library.

Prefactoring was successful in both articulating a common practice and also identifying and abstracting a range of refactorings that are generic and useful in many different situations. These days users of heavy-weight IDEs, such as Eclipse or Visual Studio .NET, have refactoring support a mouse click away.

Ken Pugh has taken on board the lessons learned from refactoring and worked them back to the beginning of the design process. Refactoring very often is about decoupling code so that dependencies between classes are minimised – this makes code more flexible, easier to maintain, and far less brittle. Hence the "Extreme Separation".

Another common problem is dependence on primitives (such as int, boolean etc), rather than on abstract data types which have semantics that reflect their contents. By using classes rather than primitives it is easier to add validation rules, enforce constraints, add additional methods and so on. This is the "Extreme Abstraction" from the subtitle. This also links in to "Extreme Readability". Using meaningful levels of abstraction is part of making code that is easy to read and understand. It's an acceptance that code needs to be developed and maintained, and should therefore be designed with that in mind.

Pugh makes his case both through argument and through the use of an extended example (coded in Java) that runs throughout the book. A web application for the rental of CDs provides ample scope for illustrating the value of the prefactoring approach. Developed using a fairly agile process, the sample project expands through a series of prototypes and requirement changes which show the pay-offs of using all those extremes.

Having a worked example gives the book a narrative that drives it along, and there are plenty of side-bars, rules, practices and other information to make it more than just a piece of source code fiction. Additionally, the final two chapters each provide another worked example, a print server and some anti-spam software respectively. For those that learn most from looking at code, these final chapters recapitulate the contents of the rest of the book.

Prefactoring

Verdict: This isn't a particularly long book, and it would have been shorter without the narrative, but it's an easy read. Its core lessons, which are to do with improving the design of software, are certainly worth learning.

Author: Ken Pugh

Publisher: O’Reilly

ISBN: 0596008740

Media: Book

List Price: £20.95

Reg price: £16.76

Internet Security Threat Report 2014

More from The Register

next story
UNIX greybeards threaten Debian fork over systemd plan
'Veteran Unix Admins' fear desktop emphasis is betraying open source
Netscape Navigator - the browser that started it all - turns 20
It was 20 years ago today, Marc Andreeesen taught the band to play
Redmond top man Satya Nadella: 'Microsoft LOVES Linux'
Open-source 'love' fairly runneth over at cloud event
Chrome 38's new HTML tag support makes fatties FIT and SKINNIER
First browser to protect networks' bandwith using official spec
Admins! Never mind POODLE, there're NEW OpenSSL bugs to splat
Four new patches for open-source crypto libraries
prev story

Whitepapers

Forging a new future with identity relationship management
Learn about ForgeRock's next generation IRM platform and how it is designed to empower CEOS's and enterprises to engage with consumers.
Why and how to choose the right cloud vendor
The benefits of cloud-based storage in your processes. Eliminate onsite, disk-based backup and archiving in favor of cloud-based data protection.
Three 1TB solid state scorchers up for grabs
Big SSDs can be expensive but think big and think free because you could be the lucky winner of one of three 1TB Samsung SSD 840 EVO drives that we’re giving away worth over £300 apiece.
Reg Reader Research: SaaS based Email and Office Productivity Tools
Read this Reg reader report which provides advice and guidance for SMBs towards the use of SaaS based email and Office productivity tools.
Security for virtualized datacentres
Legacy security solutions are inefficient due to the architectural differences between physical and virtual environments.