Abstract Factory Pattern: BMW X3 Trim Lines

The Abstract Factory Pattern helps you create related objects that are designed to work together, without needing to know exactly which classes will be used. It lets you build groups of things that match — like a set — and switch the whole group easily.

Real-Life Analogy: BMW X3 Trim Lines

Imagine you're at a BMW factory where they're building the X3. The car comes in different trims — Core Line, M Sport, and Luxury Line.

Each trim package includes a matching set of parts: seats, dashboards, and media systems. For example, the M Sport version has sport seats, a metal-trim dashboard, and a dynamic sound system. The Luxury Line has leather seats, wood trim, and an advanced infotainment system.

The car’s software doesn’t need to care which parts were installed — they all follow the same interface. But the factory decides which full set to install depending on the trim.

Benefits of Abstract Factory

This pattern ensures that all created components are compatible and work well together. It encapsulates the logic of which components belong together, improving maintainability.

It also allows for easy swapping of whole sets of functionality (themes, configurations, etc.) without changing your application logic.

• Enforces compatibility across related components
• Encapsulates creation of product families
• Supports flexible swapping of configurations or themes

What to Implement

You need:

Product interfaces (like ISeat and IDashboard), concrete classes for each trim, and factories that create these sets.

• Abstract Product Interfaces: Common contracts for families of objects
• Concrete Products: Variations for each trim line
• Abstract Factory: Interface to create all related products
• Concrete Factories: Build specific trim packages

How It Works in C#

// Abstract Products
public interface ISeat {
    void Sit();
}

public interface IDashboard {
    void Display();
}

// Core Line Products
public class CoreSeat : ISeat {
    public void Sit() => Console.WriteLine("Sitting in standard fabric seat");
}

public class CoreDashboard : IDashboard {
    public void Display() => Console.WriteLine("Core dashboard on");
}

// M Sport Products
public class MSportSeat : ISeat {
    public void Sit() => Console.WriteLine("Sitting in M Sport bucket seat");
}

public class MSportDashboard : IDashboard {
    public void Display() => Console.WriteLine("M Sport dashboard on");
}

// Luxury Line Products
public class LuxurySeat : ISeat {
    public void Sit() => Console.WriteLine("Sitting in leather comfort seat");
}

public class LuxuryDashboard : IDashboard {
    public void Display() => Console.WriteLine("Luxury dashboard on");
}

// Abstract Factory
public interface IX3Factory {
    ISeat CreateSeat();
    IDashboard CreateDashboard();
}

// Concrete Factories
public class CoreFactory : IX3Factory {
    public ISeat CreateSeat() => new CoreSeat();
    public IDashboard CreateDashboard() => new CoreDashboard();
}

public class MSportFactory : IX3Factory {
    public ISeat CreateSeat() => new MSportSeat();
    public IDashboard CreateDashboard() => new MSportDashboard();
}

public class LuxuryFactory : IX3Factory {
    public ISeat CreateSeat() => new LuxurySeat();
    public IDashboard CreateDashboard() => new LuxuryDashboard();
}

Usage:

IX3Factory factory = new LuxuryFactory();
ISeat seat = factory.CreateSeat();
IDashboard dash = factory.CreateDashboard();

seat.Sit();
dash.Display();

When Should You Use It?

Use the Abstract Factory Pattern when your app needs to work with groups of related objects that are meant to be used together. It is helpful when:

• You want to switch between object groups easily
• You want to make sure only matching objects are used together
• You don't want the rest of your code to care which exact object is used

When Not to Use It: Avoid this pattern if you are only creating a single object, or if the objects don't need to match or vary together. Factory Method may be a better fit in those cases.

Final Thoughts

The Abstract Factory Pattern is like choosing a BMW trim line. You get a full set of parts that fit together, just by picking the level you want.

Use it when you want to build consistent sets of features — and make it easy to swap them all at once.