Пример - Фабричный метод на Python

шаблоны проектирования, factory, Python, method

Пример фабричного метода на языке программирования Python

"""
Define an interface for creating an object, but let subclasses decide
which class to instantiate. Factory Method lets a class defer
instantiation to subclasses.
"""
 
import abc
 
 
class Creator(metaclass=abc.ABCMeta):
    """
    Declare the factory method, which returns an object of type Product.
    Creator may also define a default implementation of the factory
    method that returns a default ConcreteProduct object.
    Call the factory method to create a Product object.
    """
 
    def __init__(self):
        self.product = self._factory_method()
 
    @abc.abstractmethod
    def _factory_method(self):
        pass
 
    def some_operation(self):
        self.product.interface()
 
 
class ConcreteCreator1(Creator):
    """
    Override the factory method to return an instance of a
    ConcreteProduct1.
    """
 
    def _factory_method(self):
        return ConcreteProduct1()
 
 
class ConcreteCreator2(Creator):
    """
    Override the factory method to return an instance of a
    ConcreteProduct2.
    """
 
    def _factory_method(self):
        return ConcreteProduct2()
 
 
class Product(metaclass=abc.ABCMeta):
    """
    Define the interface of objects the factory method creates.
    """
 
    @abc.abstractmethod
    def interface(self):
        pass
 
 
class ConcreteProduct1(Product):
    """
    Implement the Product interface.
    """
 
    def interface(self):
        pass
 
 
class ConcreteProduct2(Product):
    """
    Implement the Product interface.
    """
 
    def interface(self):
        pass
 
 
def main():
    concrete_creator = ConcreteCreator1()
    concrete_creator.product.interface()
    concrete_creator.some_operation()
 
 
if __name__ == "__main__":
    main()