Abstract Factory Design Pattern

Definition :

Provide an interface for creating families of related or dependent objects without specifying their concrete classes.

UML class diagram :

 

Participants

The classes and/or objects participating in this pattern are:

• AbstractFactory  (ContinentFactory)
  • declares an interface for operations that create abstract products
• ConcreteFactory   (AfricaFactory, AmericaFactory)
  • implements the operations to create concrete product objects
• AbstractProduct   (Herbivore, Carnivore)
  • declares an interface for a type of product object
• Product  (Wildebeest, Lion, Bison, Wolf)
  • defines a product object to be created by the corresponding concrete factory
  • implements the AbstractProduct interface
• Client  (AnimalWorld)
  • uses interfaces declared by AbstractFactory and AbstractProduct classes.
  • Sample code in C#

Sample Code in C#

// Abstract Factory pattern -- Structural example

using System; namespace DesignPattern {   /// <summary>   /// MainApp startup class for Structural   /// Abstract Factory Design Pattern.   /// </summary>   class MainApp   {     /// <summary>     /// Entry point into console application.     /// </summary>     public static void Main()     {       // Abstract factory #1       AbstractFactory factory1 = new ConcreteFactory1();       Client client1 = new Client(factory1);       client1.Run();       // Abstract factory #2       AbstractFactory factory2 = new ConcreteFactory2();       Client client2 = new Client(factory2);       client2.Run();       // Wait for user input       Console.ReadKey();     }   }   /// <summary>   /// The 'AbstractFactory' abstract class   /// </summary>   abstract class AbstractFactory   {     public abstract AbstractProductA CreateProductA();     public abstract AbstractProductB CreateProductB();   }   /// <summary>   /// The 'ConcreteFactory1' class   /// </summary>   class ConcreteFactory1 : AbstractFactory   {     public override AbstractProductA CreateProductA()     {       return new ProductA1();     }     public override AbstractProductB CreateProductB()     {       return new ProductB1();     }   }   /// <summary>   /// The 'ConcreteFactory2' class   /// </summary>   class ConcreteFactory2 : AbstractFactory   {     public override AbstractProductA CreateProductA()     {       return new ProductA2();     }     public override AbstractProductB CreateProductB()     {       return new ProductB2();     }   }   /// <summary>   /// The 'AbstractProductA' abstract class   /// </summary>   abstract class AbstractProductA   {   }   /// <summary>   /// The 'AbstractProductB' abstract class   /// </summary>   abstract class AbstractProductB   {     public abstract void Interact(AbstractProductA a);   }   /// <summary>   /// The 'ProductA1' class   /// </summary>   class ProductA1 : AbstractProductA   {   }   /// <summary>   /// The 'ProductB1' class   /// </summary>   class ProductB1 : AbstractProductB   {     public override void Interact(AbstractProductA a)     {       Console.WriteLine(this.GetType().Name +         " interacts with " + a.GetType().Name);     }   }   /// <summary>   /// The 'ProductA2' class   /// </summary>   class ProductA2 : AbstractProductA   {   }   /// <summary>   /// The 'ProductB2' class   /// </summary>   class ProductB2 : AbstractProductB   {     public override void Interact(AbstractProductA a)     {       Console.WriteLine(this.GetType().Name +         " interacts with " + a.GetType().Name);     }   }   /// <summary>   /// The 'Client' class. Interaction environment for the products.   /// </summary>   class Client   {     private AbstractProductA _abstractProductA;     private AbstractProductB _abstractProductB;     // Constructor     public Client(AbstractFactory factory)     {       _abstractProductB = factory.CreateProductB();       _abstractProductA = factory.CreateProductA();     }     public void Run()     {       _abstractProductB.Interact(_abstractProductA);     }   } }

Output ProductB1 interacts with ProductA1 ProductB2 interacts with ProductA2

 

Reference :- http://www.dofactory.com