Head First Design Patterns, 2nd Edition

Chapter 12. Patterns of Patterns: Compound Patterns

Who would have ever guessed that Patterns could work together? You’ve already witnessed the acrimonious Fireside Chats (and you haven’t even seen the Pattern Death Match pages that the editor forced us to remove from the book), so who would have thought patterns can actually get along well together? Well, believe it or not, some of the most powerful OO designs use several patterns together. Get ready to take your pattern skills to the next level; it’s time for compound patterns.

Working together

One of the best ways to use patterns is to get them out of the house so they can interact with other patterns. The more you use patterns the more you’re going to see them showing up together in your designs. We have a special name for a set of patterns that work together in a design that can be applied over many problems: a compound pattern. That’s right, we are now talking about patterns made of patterns!

You’ll find a lot of compound patterns in use in the real world. Now that you’ve got patterns in your brain, you’ll see that they are really just patterns working together, and that makes them easier to understand.

We’re going to start this chapter by revisiting our friendly ducks in the SimUDuck duck simulator. It’s only fitting ...