Book Information
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Book Reviews
Review by Shlomi Fish, June 2004
Refactoring is improving the internal design
of a code without changing its external behaviour. This book is the definite
guide to refactoring, at least in object-oriented systems.
The first chapters of the book are rather general. They introduce the
motivation for refactoring, why it is good, why it actually speeds up
development. Also, they also give a list of "bad smells" in the code
that indicate that a refactoring is needed. (like duplicate code).
The middle part of the book which is its lion's share is a catalog of
various refactorings. These are things like extracting a method, creating
a superclass, eliminating inheritance, or creating one. The author explains
there each refactoring, when to do it, the steps for performing it most
safely, and then usually gives an example of how to do it. I found the
catalog a bit tedious to read, but interesting nonetheless. It taught
me some new techniques that I was not previously aware of.
The final chapters wrap up the book, and are also interesting to read. They
consist of an essay by William Opdyke (who wrote a very early research paper
on refactoring) titled "Refactoring, Reuse and Reality", a chapter about
Refactoring Tools, and a short
summarizing chapter by Kent Beck.
The book smells a bit of hype: Java is used as the example language (albeit
its use there is quite justified); there are many UML diagrams (which were
at first confusing to me due to the many kind of arrows they have); and there
are references of several of the so-called Design Patterns. (from the Gang
of Four book and otherwise). But they don't detract much from an
otherwise good book.
The book can also be used as a reference to look for refactorings or see
how can they be performed well. I think this book has made me more conscious
of how I refactor and write code, and I try to refactor in a way that will
minimize the errors caused by it. I'm also now more aware of the "two hats",
as Fowler puts it, of either refactoring code or adding new features.
To sum, this is a very good and important book to read, especially for
beginning programmers. I'm just not sure it justifies the $54.00 list
price. This is too much of a price for such a book.