Assumptions and References
This book assumes you are familiar with design concepts like tight- or loose-coupling and object-oriented concepts like inheritance, polymorphism, encapsulation, composition, interfaces, abstract and concrete classes, abstract and static methods and so forth.
I use Java examples in this book. I find that Java tends to be easy for most object-oriented programmers to read. I've gone out of my way to not use fancy Java features, so whether you code in C++, C#, VB.NET, Python, Ruby, Smalltalk or some other object-oriented language, you ought be able to understand the Java code in this book.
This book is closely tied to Martin Fowler's classic book, Refactoring [F].
Understanding Pattern-Directed Refactorings
To understand the pattern-directed refactorings in this book, you don't need to know every refactoring listed above. Instead, you can follow the example code that illustrates how the above refactorings are implemented. However, if you want to get the most out of this book, I do recommend that you have Refactoring [F] close by your side. It's an invaluable refactoring resource, as well as a useful aid for understanding this book.
The patterns I write about come from the classic book, Design Patterns [DP], as well as from authors such as Kent Beck, Bobby Woolf and myself. These are patterns that my colleagues and I have refactored to, towards or away from on real-world projects. By learning the art of pattern-directed refactorings, you'll understand how to refactor or towards patterns not mentioned in this book.
You don't need expert knowledge of these patterns to read this book, though some knowledge of patterns is useful. To help you understand the patterns I've written about, this book includes brief pattern summaries, UML sketches of patterns and many example implementations of patterns. To get a more detailed understanding of the patterns, I'd recommend that you study this book in conjunction with the patterns literature I reference.
This book uses UML 2.0 diagrams. If you don't know UML very well, you're in good company. I know the basics. While writing this book, I kept the third edition of Fowler's UML Distilled close by my side and referred to it often.