Factory method

Definition

The factory method is a design pattern that provides an interface for creating objects in a superclass, but allows subclasses to alter the type of objects that will be created. This pattern promotes loose coupling in software design by allowing a class to delegate the responsibility of instantiation to subclasses. It helps in managing and scaling complex systems by enabling different implementations to be produced from a common interface.

5 Must Know Facts For Your Next Test

1. The factory method pattern is categorized as a creational design pattern, focusing on object creation mechanisms.
2. It allows a class to delegate the responsibility of object instantiation to subclasses, promoting code reusability and flexibility.
3. In the factory method, the client code is independent of the specific classes that implement the product interface, enhancing code maintainability.
4. This pattern is especially useful when the exact type of object to be created isn't known until runtime, allowing for dynamic and adaptable systems.
5. Factory methods can improve testing and debugging processes by allowing mock implementations to be easily created without modifying client code.

Review Questions

• How does the factory method pattern contribute to loose coupling in software design?
  • The factory method pattern contributes to loose coupling by allowing the client code to interact with an abstract interface rather than concrete implementations. By delegating the object creation process to subclasses, it minimizes dependencies between classes and promotes flexibility. This way, changes in object creation logic or new product types can occur without affecting client code, making the system easier to maintain and extend.
• Discuss the differences between factory method and abstract factory patterns in terms of their structure and usage.
  • The factory method pattern involves a single method for creating a product, which can vary based on the subclass implementing it. In contrast, the abstract factory pattern provides an interface for creating families of related products, requiring multiple factory methods to produce different types. While both patterns promote loose coupling, the factory method focuses on individual product creation whereas the abstract factory handles a wider range of products under one roof.
• Evaluate how implementing the factory method pattern can impact software scalability and maintainability.
  • Implementing the factory method pattern can significantly enhance software scalability and maintainability by separating object creation logic from business logic. As new product types emerge, developers can introduce new subclasses without modifying existing code, reducing risks of bugs during updates. This separation makes it easier to manage changes over time and adapt to evolving requirements, fostering a more resilient architecture that can grow alongside business needs.

Related terms

Abstract Factory: A design pattern that provides an interface for creating families of related or dependent objects without specifying their concrete classes.

Singleton: A design pattern that restricts a class to a single instance and provides a global point of access to that instance.

Polymorphism: A feature of object-oriented programming that allows objects of different classes to be treated as objects of a common superclass, enabling methods to use objects of different types at runtime.