Bridge Design Pattern -- Design Pattern

    Decouple an abstraction from its implementation so that the two can vary independently.

Participants

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

• Abstraction(Business Object)

         Defines the abstraction's interface.Maintains a reference to an object of type Implementer.

• Refined Abstraction   (Customers Business Object)

          Extends the interface defined by Abstraction.

• Implementer(Data Object)

         Defines the interface for implementation classes. This interface doesn't have to correspond exactly to Abstraction's interface; in fact the two interfaces can be quite different. Typically the Implementation interface provides only primitive operations, and Abstraction defines higher-level operations based on these primitives.

• Concrete Implementer(Customers Data Object)

         Implements the Implementer interface and define its concrete implementation.

Sample Code:

// Bridge pattern -- Structural example

using System;  Namespace Bridge. Structural {   /// <summary>   /// MainApp startup class for Structural   /// Bridge Design Pattern.   /// </summary>   class MainApp   {     /// <summary>     /// Entry point into console application.     /// </summary>     static void Main()     {       Abstraction ab = new RefinedAbstraction();       // Set implementation and call       ab.Implementor = new ConcreteImplementorA();       ab.Operation();       // Change implemention and call       ab.Implementor = new ConcreteImplementorB();       ab.Operation();        // Wait for user       Console.ReadKey();     }   }    /// <summary>   /// The 'Abstraction' class   /// </summary>   class Abstraction   {     protected Implementor implementor;      // Property     public Implementor Implementor     {       set { implementor = value; }     }      public virtual void Operation()     {       implementor.Operation();     }   }    /// <summary>   /// The 'Implementor' abstract class   /// </summary>   abstract class Implementor   {     public abstract void Operation();   }    /// <summary>   /// The 'RefinedAbstraction' class   /// </summary>   class RefinedAbstraction : Abstraction   {     public override void Operation()     {       implementor.Operation();     }   }   /// <summary>   /// The 'ConcreteImplementorA' class   /// </summary>   class ConcreteImplementorA : Implementor   {     public override void Operation()     {       Console.WriteLine("ConcreteImplementorA Operation");     }   }    /// <summary>   /// The 'ConcreteImplementorB' class   /// </summary>   class ConcreteImplementorB : Implementor   {     public override void Operation()     {       Console.WriteLine("ConcreteImplementorB Operation");     }   } }

Output ConcreteImplementorA Operation ConcreteImplementorB Operation