Pythonistas

Factory Pattern

Dominic Yeboah's photo
Dominic Yeboah
·

1 min read


The Factory pattern is a creational design pattern that provides an interface
for creating objects in a super class, but allows subclasses to
alter the type of objects that will be created.

class Animal:
    def speak(self):
        pass

class Dog(Animal):
    def speak(self):
        return "Woof!"

class Cat(Animal):
    def speak(self):
        return "Meow!"

class AnimalFactory:
    def create_animal(self, animal_type):
        if animal_type == "Dog":
            return Dog()
        elif animal_type == "Cat":
            return Cat()
        else:
            raise ValueError("Invalid animal type")

factory = AnimalFactory()
dog = factory.create_animal("Dog")
print(dog.speak()) # Woof!
cat = factory.create_animal("Cat")
print(cat.speak()) # Meow!

In this example, the Animal class is the superclass and the Dog and Cat classes are subclasses that inherit from Animal. The AnimalFactory class is the factory class that has a method create_animal that takes an animal_type argument and returns an instance of the corresponding class. The factory method can be used to create objects of different types, depending on the value of the animal_type argument.

Python