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from abc import ABC, abstractmethod, ABCMeta |
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__all__ = ['GenericMediator', 'BaseComponent'] |
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class Mediator(ABC): |
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""" |
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The Mediator interface declares a method used by components to notify the |
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mediator about various events. The Mediator may react to these events and |
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pass the execution to other components. |
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""" |
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@abstractmethod |
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def notify(self, sender: object, event: str) -> None: |
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"""[summary] |
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Args: |
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sender (object): [description] |
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event (str): [description] |
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""" |
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raise NotImplementedError |
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class GenericMediator(Mediator, metaclass=ABCMeta): |
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"""Abstract Mediator class that automatically configures components received as *args through the constructor. |
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""" |
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def __new__(cls, *components, **kwargs): |
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x = super().__new__(cls) |
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for i, component in enumerate(components): |
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setattr(x, f'_component{i+1}', component) |
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getattr(x, f'_component{i+1}').mediator = x |
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return x |
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class BaseComponent: |
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""" |
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The Base Component provides the basic functionality of storing a mediator's |
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instance inside component objects. |
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""" |
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def __init__(self, mediator: Mediator = None) -> None: |
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self._mediator = mediator |
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@property |
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def mediator(self) -> Mediator: |
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return self._mediator |
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@mediator.setter |
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def mediator(self, mediator: Mediator) -> None: |
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self._mediator = mediator |
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if __name__ == "__main__": |
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# The client code. |
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class ConcreteMediator(GenericMediator): |
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def notify(self, sender: object, event: str) -> None: |
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if event == "A": |
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print("Mediator reacts on A and triggers following operations:") |
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self._component2.do_c() |
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elif event == "D": |
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print("Mediator reacts on D and triggers following operations:") |
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self._component1.do_b() |
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self._component2.do_c() |
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""" |
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Concrete Components implement various functionality. They don't depend on other |
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components. They also don't depend on any concrete mediator classes. |
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""" |
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class Component1(BaseComponent): |
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def do_a(self) -> None: |
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print("Component 1 does A.") |
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self.mediator.notify(self, "A") |
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def do_b(self) -> None: |
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print("Component 1 does B.") |
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self.mediator.notify(self, "B") |
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class Component2(BaseComponent): |
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def do_c(self) -> None: |
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print("Component 2 does C.") |
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self.mediator.notify(self, "C") |
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def do_d(self) -> None: |
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print("Component 2 does D.") |
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self.mediator.notify(self, "D") |
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c1 = Component1() |
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c2 = Component2() |
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my_mediator = ConcreteMediator(c1, c2) |
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print("Client triggers operation A.") |
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c1.do_a() |
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print("\n", end="") |
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print("Client triggers operation D.") |
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c2.do_d() |
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boromir674 /
so-magic
