Tag Archives: decorator

Example for singleton decorator pattern in python

I know there is not very common in Python to use the singleton pattern, but I found a nice implementation of this pattern in Python 3 Patterns, Recipes and Idioms book. Starting with that example I implemented an equivalent of the well known PHP getConnection example.

You have the code below:

This is the class that implements the Singleton pattern.

Now, we create a class and we decorate it with the Singleton class. Let’s import also MySQLdb module *.

Let’s test this:

You will see something like:

As you can see there is only one object.

For fun, let’s remove the line “@Singleton” and re-run the example. This time you will see different objects:

You can find the fully example here.

* If you don’t know how to install MySQLdb, you can check the previous post.