Source code for asab.abc.singleton

class Singleton(type):

	"""
The `singleton pattern <https://en.wikipedia.org/wiki/Singleton_pattern>`_ is a software design pattern that restricts the instantiation of a class to one object.

*Note*: The implementation idea is borrowed from "`Creating a singleton in Python <https://stackoverflow.com/questions/6760685/creating-a-singleton-in-python>`_" question on StackOverflow.
	"""

	_instances = {}

	def __call__(cls, *args, **kwargs):
		if cls not in cls._instances:
			cls._instances[cls] = super(Singleton, cls).__call__(*args, **kwargs)
		return cls._instances[cls]