mirror of
https://github.com/rjNemo/design-patterns
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53 lines
1.5 KiB
Python
53 lines
1.5 KiB
Python
from __future__ import annotations
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from abc import ABC, abstractmethod
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# from behavioral.visitor.visitor import Visitor
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class Component(ABC):
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"""
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The Component interface declares an `accept` method that should take the
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base visitor interface as an argument.
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"""
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@abstractmethod
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def accept(self, visitor: "Visitor") -> None:
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pass
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class ConcreteComponentA(Component):
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"""
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Each Concrete Component must implement the `accept` method in such a way
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that it calls the visitor's method corresponding to the component's class.
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"""
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def accept(self, visitor: "Visitor") -> None:
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"""
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Note that we're calling `visitConcreteComponentA`, which matches the
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current class name. This way we let the visitor know the class of the
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component it works with.
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"""
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visitor.visit_concrete_component_a(self)
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def exclusive_method_of_concrete_component_a(self) -> str:
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"""
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Concrete Components may have special methods that don't exist in their
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base class or interface. The Visitor is still able to use these methods
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since it's aware of the component's concrete class.
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"""
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return "A"
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class ConcreteComponentB(Component):
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"""
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Same here: visitConcreteComponentB => ConcreteComponentB
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"""
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def accept(self, visitor: "Visitor") -> None:
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visitor.visit_concrete_component_b(self)
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def special_method_of_concrete_component_b(self) -> str:
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return "B"
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