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()
