Decorators in Python. This type of design pattern comes under structural pattern as this pattern acts as a wrapper to existing class. This is actually very maintainable, when done correctly, which is why I posted this question. Decorators are usually called before the definition of a function you want to decorate. Decorators provide a flexible alternative to subclassing for extending functionality. """ Python makes implementing this pattern relatively easier as compared to other languages, due to its builtin feature called decorators. I wanted to find the way to this in Python. This pattern is very common in Python applications, as it allows two or more subsystems to communicate without knowing much about each other, what is formally known as a "decoupled" design. In this tutorial, we'll show the reader how they can use decorators in their Python functions. The decorator design pattern provides a way to modify a function, often by adding functionality before and after it runs. Python has an interesting feature called decorators to add functionality to an existing code. A function registration decorator that takes no arguments has the following structure: First, you need to understand that the word “decorator” was used with some trepidation in Python, because there was concern that it would be completely confused with the Decorator pattern from the Design Patterns book.At one point other terms were considered for the feature, but “decorator” seems to be the one that sticks. In this tutorial, you will learn how you can create a decorator and why you should use it. A decorator is a design pattern in Python that allows a user to add new functionality to an existing object without modifying its structure. import abc class Component(metaclass=abc.ABCMeta): """ Define the interface for objects that can have responsibilities added to them dynamically. However, wrapper() has a reference to the original say_whee() as func, and calls that function between the two calls to print(). Python Decorators A decorator takes in a function, adds some functionality and returns it. – Björn Pollex Jun 26 '10 at 11:13 Decorators vs. the Decorator Pattern¶. The decorator pattern is a design pattern used in statically typed object-oriented programming languages to allow functionality to be added to objects at run time; Python decorators add functionality to functions and methods at definition time, and thus are a higher-level construct than decorator-pattern classes. Python is rich with powerful features and expressive syntax. A Python decorator is a specific change to the Python syntax that allows us to more conveniently alter functions and methods (and possibly classes in a future version). One of my favorites is decorators. Decorator pattern allows a user to add new functionality to an existing object without altering its structure. This is ideal when … In Python, functions are first-class objects, so they can be passed into and out of functions just like any other variable. The Decorator Design Pattern gives us a method to add new functionality to an object, dynamically. @THC4K: The decorator pattern (as opposed to python decorators) is used to add behavior to an object at runtime. Before moving on, let’s have a look at a second example. In the context of design patterns, decorators dynamically alter the functionality of a function, method or class without having to directly use subclasses. This supports more readable applications of the DecoratorPattern but also other uses as well. Put simply: decorators wrap a function, modifying its behavior. Decorator Design Pattern in Python Back to Decorator description """ Attach additional responsibilities to an object dynamically. Because wrapper() is a regular Python function, the way a decorator modifies a function can change dynamically.