Pattern Hatching: Design Patterns Applied 1st by Vlissides, John (1998) Paperback

Software Patterns Series

by John M. Vlissides

Author John Vlissides is a member of the so-called Gang of writers of the bestselling and influential Design Elements of Reusable Object-Oriented Software, a catalog of 23 design patterns. This more recent book delivers considerable insight on using and applying software design patterns--reusable designs for common programming problems--and compiles the author's further experience with patterns. Pattern Hatching first defends the patterns movement by offering 10 myths about patterns, which provide a framework for thinking about the role of patterns in today's software. (While not a silver bullet, the author argues for the continued importance of patterns throughout software engineering.) The next section shows how to apply several patterns (drawn from the original 23) in a file system; the author uses and describes common patterns such as the Composite, Visitor, Proxy, and Singleton. To help illustrate how to use patterns and how they work together, the author also provides C++ source code for the designs in the book.

Part of the fun of reading Pattern Hatching is getting the author's insight on the origin of thinking about patterns, including several patterns that were actually left out of the original book, such as the Generation Gap pattern and the Multicast pattern.

For readers who are familiar with Design Patterns, Pattern Hatching is a lively behind-the-scenes look at one of the most important recent developments in software design. --Richard Dragan

Genres: Programming, Computer Science, Technical, Nonfiction, Technology, Computers, Software

Paperback

First published July 2, 1998

Reviews

[Amrullah Zunzunia · Rating 3 out of 5]

John Vlissides, one of the GoF authors, goes through design of an imaginary file system, exploring and applying design patterns. While a good read, I had a tough time grasping everything because code examples were in C++.

[Benoit Blanchon · Rating 3 out of 5]

This book is quite good, but there is not much to take away.

First, unlike the GoF, this book only targets the C++ language, and even if you're a C++ developer, there is still very little to learn. Let me explain.

In the first part, we see John apply the GoF design patterns to a sample program - that's the "Design Patterns Applied" announced in the subtitle.
I liked this part of the book but found that the given example (a file system modeled with objects) is not realistic and feeds the narrative that object-oriented designs are fancy concepts that cannot be applied in real applications.

The second part revisits some of the classic patterns (observer, visitor, and singleton in particular) to address some of the issues that were not covered in the GoF. For example, it talks about the initialization order of the singletons and about the coupling in the visitor pattern. This part is interesting, but I think that those issues are well-known now.

John also presents two "new" patterns: Generation Gap, and Typed Message. The first one consists in using an abstract class for code generated by a tool (for example, a UI designer) and a derived class for customizations so that the generator can override the files without losing the user-written code. The second pattern is a variation of Observer, where the callback receives a strongly typed message so that you can listen to specific events instead of watching the whole object.
These patterns are useful, and we've seen them used in the wild, but they could be presented in just a few pages.

This is roughly what there is to learn in this book; as you can see, there is very little material. However, I must say that John does a very good writing job which makes this book pleasant to read.

[Rustam · Rating 3 out of 5]

A fairly decent primer on rationalizing how and why to use certain design patterns.

[Phuong Phan · Rating 4 out of 5]

great book.