The Factory Method Pattern Explained and Implemented in Java | Creational Design Patterns | Geekific

Summary

In this video, the Factory Method Design Pattern is explained through the example of a burger delivery app. Starting with a simple factory approach, the video illustrates how code can become difficult to modify as new products (like different burgers) are added. To resolve this, the Factory Method pattern is introduced, which allows for flexible product creation and adheres to key design principles like the Open-Closed and Single Responsibility Principles. The video concludes with a preview of the Abstract Factory pattern, showcasing how it can further improve extensibility in complex systems.

Takeaways

• 😀 Simple Factory Idiom encapsulates object creation into one class (Factory) to avoid direct instantiation in business logic.
• 😀 The Factory Method Design Pattern is a more formal approach, delegating object creation to subclasses, enhancing flexibility.
• 😀 The Open-Closed Principle (OCP) means that software should be open for extension but closed for modification to prevent changes to existing code when adding new features.
• 😀 The Single Responsibility Principle (SRP) suggests that classes should have only one responsibility, which in this case is separating object creation logic from business logic.
• 😀 Encapsulating burger creation in a factory class allows adding new products without modifying the main restaurant logic, preserving the design principles.
• 😀 The Simple Factory, though helpful, violates the Open-Closed Principle as it requires adding if-statements to handle new burger types.
• 😀 The Factory Method pattern resolves the limitation of the Simple Factory by abstracting the creation process and delegating it to subclasses of the base class.
• 😀 Using the Factory Method pattern, the code that orders burgers no longer depends on specific product types, making it more extensible and less coupled.
• 😀 The Factory Method pattern is useful when you don’t know beforehand which type of objects your code will work with, providing a way to handle new product types without breaking existing code.
• 😀 The Factory Method allows centralized control over the product creation process, adhering to the Single Responsibility and Open-Closed Principles.
• 😀 Introducing the Abstract Factory pattern in the next video will further address issues with multiple variants of the same product (e.g., different burger styles).

Q & A

What is the main purpose of using the Factory Method Pattern in the burger delivery app?

The main purpose of using the Factory Method Pattern is to centralize the creation of burger objects in one place, making it easier to add new burger types without modifying existing code. This pattern helps maintain the open/closed principle and the single responsibility principle, allowing for easier extensibility and modification of the app.

What is the limitation of the Simple Factory Idiom in the burger delivery app?

The limitation of the Simple Factory Idiom is that it creates a tight coupling between the object creation code and the rest of the application. As new types of burgers are added, the factory method will require modifications, violating the open/closed principle, and leading to repetitive code changes.

How does the Factory Method Pattern address the limitations of the Simple Factory Idiom?

The Factory Method Pattern addresses these limitations by delegating the responsibility of creating burger objects to subclasses, each of which implements the factory method. This way, new burger types can be added by creating new subclasses without altering the existing code, ensuring the code remains closed for modification.

What design principles are followed by using the Factory Method Pattern?

The Factory Method Pattern helps follow the open/closed principle (code should be open for extension but closed for modification) and the single responsibility principle (the creation logic is encapsulated in one place, separate from business logic).

What is the role of inheritance in the Factory Method Pattern?

In the Factory Method Pattern, inheritance plays a key role in allowing subclasses of the 'Restaurant' class to implement their own version of the factory method for creating specific types of burgers. This enables different restaurant types to have their own creation logic without modifying the base class.

Why is the Factory Method Pattern considered a 'creational' design pattern?

The Factory Method Pattern is considered a 'creational' design pattern because it deals with the process of creating objects. It abstracts and centralizes the creation logic, providing a way to instantiate objects without specifying the exact class to be instantiated.

How does the Factory Method Pattern improve the maintainability of the burger delivery app?

By centralizing the creation logic in one place and separating it from business logic, the Factory Method Pattern makes it easier to maintain and extend the app. New types of burgers can be added by simply creating new subclasses without modifying the core app logic, leading to less code duplication and reduced risk of introducing errors.

What problem does the speaker identify when the restaurant introduces a new variation, like Italian-style burgers?

The speaker identifies that adding a new burger variation, such as Italian-style burgers, would require modifications to the existing factory method, making the code open for changes. This could lead to potential issues as the app grows, and the speaker suggests this scenario will be addressed by the Abstract Factory Pattern in the next video.

Why does the speaker suggest the Factory Method Pattern is not a 'full-fledged' design pattern?

The speaker suggests the Factory Method Pattern is not a 'full-fledged' design pattern because, in the simple implementation shown, the factory method still requires modification when new burger types are added, which violates the open/closed principle. The speaker refers to the Abstract Factory Pattern as a more robust solution to this issue.

What is the next design pattern that the speaker plans to discuss in the series?

The speaker plans to discuss the Abstract Factory Pattern in the next video, which will address more complex scenarios, such as adding regional variations like Italian-style burgers, and will provide a more flexible solution to object creation in large applications.