Bridge Pattern

Bridge Pattern 

Gamma Categorization: Structural Design Pattern
Summary: A mechanism that decouples an interface (hierarchy) from an implementation (hierarchy).

Sample Code

Problem: We want to be able to implement the photo storage mechanism.

Code

public interface IStorage

{

    void SaveFile(byte[] bytes);

}

public class InternalStorage : IStorage

{

    public void SaveFile(byte[] bytes)

    {

        System.Console.WriteLine("File sent to disk.");

    }

}

    public class CloudStorage : IStorage

{

    public void SaveFile(byte[] bytes)

    {

        System.Console.WriteLine("File sent to server.");

    }

}

public class DigitalCamera

{

    private IStorage storage;

    public DigitalCamera(IStorage storage)

    {

        this.storage = storage;

    }

    public void TakePhoto()

    {

        // Simulation of taking a photo from the digital image sensor

        byte[] photo = new byte[1024];

        System.Console.WriteLine("Photo retrieved.");

        // Saving photo

        storage.SaveFile(photo);

    }

}

Usage

var camera = new DigitalCamera(new CloudStorage());

camera.TakePhoto();

Output

Photo retrieved.
File sent to server.