Skip to content

Singleton

MDTC Singleton module.

Singleton

Simplistic singleton-pattern class to inherit from.

Best used for when you require only a single instance of a specific class to ever be allowed to exist in your program.

Source code in mdtc/singleton.py 
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
class Singleton:
    """
    Simplistic singleton-pattern class to inherit from.

    Best used for when you require only a single instance of a specific class
    to ever be allowed to exist in your program.
    """

    def __new__(cls, *args: Any, **kwargs: Any) -> "Singleton":
        """
        Intercept the `__new__` call and return an existing instance of this class instead.
        """
        if not hasattr(cls, "instance"):
            cls.instance = super(Singleton, cls).__new__(cls)
        return cls.instance

    @classmethod
    def clear_instance(cls) -> None:
        """Destroys current instance and re-sets the singleton."""
        del cls.instance

__new__(*args, **kwargs)

Intercept the __new__ call and return an existing instance of this class instead.

Source code in mdtc/singleton.py 
20
21
22
23
24
25
26
def __new__(cls, *args: Any, **kwargs: Any) -> "Singleton":
    """
    Intercept the `__new__` call and return an existing instance of this class instead.
    """
    if not hasattr(cls, "instance"):
        cls.instance = super(Singleton, cls).__new__(cls)
    return cls.instance

clear_instance() classmethod

Destroys current instance and re-sets the singleton.

Source code in mdtc/singleton.py 
28
29
30
31
@classmethod
def clear_instance(cls) -> None:
    """Destroys current instance and re-sets the singleton."""
    del cls.instance