pattern-singleton

================= Pattern Singleton

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Description

Singleton is a creational design pattern that lets you ensure that a class has only one instance, while providing a global access point to this instance.
This implementation of Singleton Design Pattern is based on metaclass method.

* Free software: `MIT <https://github.com/MarcinMysliwiec/pattern_singleton/blob/master/LICENSE>`__ license
* But I would appreciate a star on `GitHub <https://github.com/MarcinMysliwiec>`__

Multithreaded

This method provide proper handling for multi-thread environment by closing public threading lock while creating instance of Singleton subclass.

Installation

Just use (No other package is needed):

.. code-block:: sh

    $ pip install pattern-singleton


Example Usage

.. code-block:: python

from pattern_singleton import Singleton


class Example(metaclass=Singleton):
    def __init__(self):
        self.variable = 1


if __name__ == '__main__':
    example_01 = Example()
    example_02 = Example()

    print(example_01.variable)  # displays 1
    print(example_02.variable)  # displays 1

    example_01.variable = 2     # changes value for every instance of Example class

    print(example_01.variable)  # displays 2
    print(example_02.variable)  # displays 2

Credits

This package was created by Marcin Mysliwiec <https://github.com/MarcinMysliwiec>__ with Cookiecutter_ and the audreyr/cookiecutter-pypackage_ project template.

.. _Cookiecutter: https://github.com/audreyr/cookiecutter .. _audreyr/cookiecutter-pypackage: https://github.com/audreyr/cookiecutter-pypackage