This article describes the Abstract Factory Design Pattern design pattern. This is a creational design pattern, a category of design pattern used by software engineers, when writing computer programs.

Introduction

The Abstract Factory Design Pattern pattern is a design pattern, used in software engineering to grouping similar objects without needing to specifying their concrete classes. This allows the developer to outline the methods and objects of the final concrete factories, so that all share an expected set of methods and classes. Objects are typically just represented as interfaces, allowing concrete objects to be varied, but always have the important shared features.

This pattern defines an Abstract Factory (CarFactory) which has Abstract Products (ICar), which is used by the Client to create Concrete Factories (SaloonCarFactory, HatchbackCarFactory) with Concrete Products (SaloonCar, HatchbackCar)

This pattern is defined as a Creational design pattern because it defines the base templates for factories that create objects.

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Benefits

Allows the application to be more portable and extensible.
Allows new derived types to be added, without changing any core/shared properties or methods.
Reduces the amount of conditional logic needed (eg "if car is Saloon, do this, else do that")

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Examples of the pattern

A Real world example would be a car factory, that produced several models of car. You would instantiate a concrete implementation of the "car factory" class to make a saloon car, or hatchback model. That concrete factory can both make cars, totally different cars, but both factories have "AddWheels" and "InsertEngine" methods. Each of the resulting car objects have Colour and NumberPlate properties, as well as Brake and Accelerate methods, because all cars are of type ICar.
 

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See Also

• Software Design Pattern
• Creational Design Pattern

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Community Resources

• Abstract Factory Design Pattern (C#, Console)
• Abstract Factory Pattern, UML diagram (Java)
• Understanding Factory Method and Abstract Factory Patterns (C++)
• Abstract Factory Pattern (Java)
• An example Abstract Factory design pattern implementation (C++)

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References section

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