Example - Abstract Factory in Python

abstract, factory, abc, python

An example of an abstract factory in the Python programming language

"""
Provide an interface for creating families of related or dependent
objects without specifying their concrete classes.
"""
 
import abc
 
 
class AbstractFactory(metaclass=abc.ABCMeta):
    """
    Declare an interface for operations that create abstract product
    objects.
    """
 
    @abc.abstractmethod
    def create_product_a(self):
        pass
 
    @abc.abstractmethod
    def create_product_b(self):
        pass
 
 
class ConcreteFactory1(AbstractFactory):
    """
    Implement the operations to create concrete product objects.
    """
 
    def create_product_a(self):
        return ConcreteProductA1()
 
    def create_product_b(self):
        return ConcreteProductB1()
 
 
class ConcreteFactory2(AbstractFactory):
    """
    Implement the operations to create concrete product objects.
    """
 
    def create_product_a(self):
        return ConcreteProductA2()
 
    def create_product_b(self):
        return ConcreteProductB2()
 
 
class AbstractProductA(metaclass=abc.ABCMeta):
    """
    Declare an interface for a type of product object.
    """
 
    @abc.abstractmethod
    def interface_a(self):
        pass
 
 
class ConcreteProductA1(AbstractProductA):
    """
    Define a product object to be created by the corresponding concrete
    factory.
    Implement the AbstractProduct interface.
    """
 
    def interface_a(self):
        pass
 
 
class ConcreteProductA2(AbstractProductA):
    """
    Define a product object to be created by the corresponding concrete
    factory.
    Implement the AbstractProduct interface.
    """
 
    def interface_a(self):
        pass
 
 
class AbstractProductB(metaclass=abc.ABCMeta):
    """
    Declare an interface for a type of product object.
    """
 
    @abc.abstractmethod
    def interface_b(self):
        pass
 
 
class ConcreteProductB1(AbstractProductB):
    """
    Define a product object to be created by the corresponding concrete
    factory.
    Implement the AbstractProduct interface.
    """
 
    def interface_b(self):
        pass
 
 
class ConcreteProductB2(AbstractProductB):
    """
    Define a product object to be created by the corresponding concrete
    factory.
    Implement the AbstractProduct interface.
    """
 
    def interface_b(self):
        pass
 
 
def main():
    for factory in (ConcreteFactory1(), ConcreteFactory2()):
        product_a = factory.create_product_a()
        product_b = factory.create_product_b()
        product_a.interface_a()
        product_b.interface_b()
 
 
if __name__ == "__main__":
    main()