Factory Method Pattern Overview

Design Pattern: Factory Method Pattern

Problem/Code Analysis:

• The provided code snippet demonstrates the Factory Method Pattern where the ShapeFactory class is responsible for creating instances of different shapes (Circle and Square) based on a given shape type.
• The ShapeFactory acts as a Factory class that encapsulates the object creation logic, decoupling the client code from the specific classes being created.

Code Template - Python:

from abc import ABC, abstractmethod

class Shape(ABC):
    @abstractmethod
    def draw(self):
        pass

class Circle(Shape):
    def draw(self):
        print("Circle: draw() method")

class Square(Shape):
    def draw(self):
        print("Square: draw() method")

class ShapeFactory:
    def create_shape(self, shape_type):
        if shape_type == 'Circle':
            return Circle()
        elif shape_type == 'Square':
            return Square()
        else:
            return None

# Client code
shape_factory = ShapeFactory()
circle = shape_factory.create_shape('Circle')
circle.draw()

square = shape_factory.create_shape('Square')
square.draw()

Implementation Details:

• Factory Method Pattern: Offers an interface for creating instances of a class, but allows subclasses to alter the type of objects that will be created.
• ShapeFactory: Encapsulates the creation logic for different shapes, providing a method create_shape() to instantiate specific shapes.
• Shape, Circle, Square: Represents the hierarchy of Shape classes where Circle and Square extend the abstract class Shape and implement the draw method.
• Client Code: Requests shape instances from the ShapeFactory without knowing the specific class that will be created, promoting flexibility and maintainability.

Comments:

• The Factory Method Pattern promotes loose coupling by delegating the responsibility of object creation to a separate class (ShapeFactory).
• It enhances code scalability as new shape classes can be added easily without modifying the existing client code.
• The use of abstract classes ensures a common interface for different shapes, enabling polymorphic behavior.

By following the Factory Method Pattern, the code structure is organized, maintainable, and adheres to the principles of object-oriented design.