Summary
This chapter covered the decorator pattern and its relationship to the Python programming language. We used the decorator pattern conveniently to extend the behavior of an object without using inheritance. Python, with its built-in decorator feature, extends the decorator concept even more, by allowing us to extend the behavior of any callable (function, method, or class) without using inheritance or composition.
We have seen a few examples of real-world objects that are decorated, such as cameras. From a software point of view, both Django and Pyramid use decorators to achieve different goals, such as controlling HTTP compression and caching.
The decorator pattern is a great solution for implementing cross-cutting concerns because they are generic and do not fit well into the OOP paradigm. We mentioned several categories of cross-cutting concerns in the Use cases section. In fact, in the Implementation section, a cross-cutting concern was demonstrated: memoization. We...
