monty.design_patterns module
Some common design patterns such as singleton and cached classes.
class monty.design_patterns.NullFile()
Bases: object
A file object that is associated to /dev/null.
no-op
class monty.design_patterns.NullStream()
Bases: object
A fake stream with a no-op write.
write(*args)
Does nothing… :param args:
monty.design_patterns.cached_class(klass: type[Klass])
Decorator to cache class instances by constructor arguments. This results in a class that behaves like a singleton for each set of constructor arguments, ensuring efficiency.
Note that this should be used for immutable classes only. Having a cached mutable class makes very little sense. For efficiency, avoid using this decorator for situations where there are many constructor arguments permutations.
The keywords argument dictionary is converted to a tuple because dicts are mutable; keywords themselves are strings and so are always hashable, but if any arguments (keyword or positional) are non-hashable, that set of arguments is not cached.
monty.design_patterns.singleton(cls)
This decorator can be used to create a singleton out of a class.
Usage:
@singleton
class MySingleton():
def __init__():
pass