Commit 6993592
| Original file line number | Diff line number | Diff line change | |
|---|---|---|---|
@@ -37,6 +37,7 @@ Current Patterns: | |||
| 37 | 37 | | [prototype](prototype.py) | use a factory and clones of a prototype for new instances (if instantiation is expensive) | | |
| 38 | 38 | | [proxy](proxy.py) | an object funnels operations to something else | | |
| 39 | 39 | | [publish_subscribe](publish_subscribe.py) | a source syndicates events/data to 0+ registered listeners | | |
| 40 | + | [registry](registry.py) | keeping track of all subclasses of a given class | | ||
| 40 | 41 | | [specification](specification.py) | business rules can be recombined by chaining the business rules together using boolean logic | | |
| 41 | 42 | | [state](state.py) | logic is org'd into a discrete number of potential states and the next state that can be transitioned to | | |
| 42 | 43 | | [strategy](strategy.py) | selectable operations over the same data | | |
| Original file line number | Diff line number | Diff line change | |
|---|---|---|---|
@@ -0,0 +1,49 @@ | |||
| 1 | + #!/usr/bin/env python | ||
| 2 | + # -*- coding: utf-8 -*- | ||
| 3 | + | ||
| 4 | + | ||
| 5 | + class RegistryHolder(type): | ||
| 6 | + | ||
| 7 | + REGISTRY = {} | ||
| 8 | + | ||
| 9 | + def __new__(cls, name, bases, attrs): | ||
| 10 | + new_cls = type.__new__(cls, name, bases, attrs) | ||
| 11 | + """ | ||
| 12 | + Here the name of the class is used as key but it could be any class | ||
| 13 | + parameter. | ||
| 14 | + """ | ||
| 15 | + cls.REGISTRY[new_cls.__name__] = new_cls | ||
| 16 | + return new_cls | ||
| 17 | + | ||
| 18 | + @classmethod | ||
| 19 | + def get_registry(cls): | ||
| 20 | + return dict(cls.REGISTRY) | ||
| 21 | + | ||
| 22 | + | ||
| 23 | + class BaseRegisteredClass(metaclass=RegistryHolder): | ||
| 24 | + """ | ||
| 25 | + Any class that will inherits from BaseRegisteredClass will be included | ||
| 26 | + inside the dict RegistryHolder.REGISTRY, the key being the name of the | ||
| 27 | + class and the associated value, the class itself. | ||
| 28 | + """ | ||
| 29 | + pass | ||
| 30 | + | ||
| 31 | + if __name__ == "__main__": | ||
| 32 | + print("Before subclassing: ") | ||
| 33 | + for k in RegistryHolder.REGISTRY: | ||
| 34 | + print(k) | ||
| 35 | + | ||
| 36 | + class ClassRegistree(BaseRegisteredClass): | ||
| 37 | + | ||
| 38 | + def __init__(self, *args, **kwargs): | ||
| 39 | + pass | ||
| 40 | + print("After subclassing: ") | ||
| 41 | + for k in RegistryHolder.REGISTRY: | ||
| 42 | + print(k) | ||
| 43 | + | ||
| 44 | + ### OUTPUT ### | ||
| 45 | + # Before subclassing: | ||
| 46 | + # BaseRegisteredClass | ||
| 47 | + # After subclassing: | ||
| 48 | + # BaseRegisteredClass | ||
| 49 | + # ClassRegistree | ||
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