Top Highlights

• If you aren’t an experienced object-oriented designer, then start with the simplest and most common
• One thing expert designers know not to do is solve every problem from first principles.
• Christopher Alexander says, “Each pattern describes a problem which occurs over and over again in our environment, and then describes the core of the solution to that problem, in such a way that you can use this solution a million times over, without ever doing it the same way twice” [AIS+77, page x].
• pattern has four essential elements:
• The design patterns in this book are descriptions of communicating objects and classes that are customized to solve a general design problem in a particular context.