In this chapter you've seen five different design patterns:
Although each pattern handles a different design issue, one feature is common to them all. After the work to develop and implement the pattern is finished, the code to actually use it is very simple and flexible. Patterns allow developers and software designers to share complex ideas with just a single term. They're also reusable ideas. The same design pattern can be a solution in very different types of software. Often you'll see design patterns incorporated into a language or framework so if you know about them, you'll understand how they are supposed to work within that language.
The five patterns presented here are just a small subset of the design patterns that exist. You should continue to explore design patterns on your own they're a great tool for a serious developer.