Skip to main content

Facade Pattern

Facade Pattern 


Gamma Categorization: Structural Design Pattern
Summary: Provide a unified interface to a set of interfaces in a subsystem. Façade defines a higher-level interface that makes the subsystem easier to use.

Sample Code

Problem: We want a facade for our digital camera subsystems.

public class DigitalCameraFacade
{
    ICamera camera;        
    IStorageManager storageManager;
    INetworkManager networkManager;

    public DigitalCameraFacade(ICamera camera, IStorageManager storageManager, INetworkManager networkManager)
    {
        this.camera = camera;            
        this.storageManager = storageManager;
        this.networkManager = networkManager;
    }

    public void TakePhoto()
    {
        var photo = camera.TakePhoto();
        storageManager.WriteFile(photo);
        networkManager.Send(photo);
    }
}

public interface ICamera
{
    byte[] TakePhoto();
}

public class DSLR : ICamera
{
    public byte[] TakePhoto()
    {
        System.Console.WriteLine("Taking photo.");
        return new byte[1024];
    }
}

public interface IStorageManager
{
    byte[] ReadFile();
    void WriteFile(byte[] file);        
}

public class SDCardManager : IStorageManager
{
    public byte[] ReadFile()
    {
        System.Console.WriteLine("Reading file to drive.");
        return new byte[1024];
    }
    public void WriteFile(byte[] file) => System.Console.WriteLine("Writing file from drive.");
}

public interface INetworkManager
{
    void Connect();
    void Send(byte[] file);
}

public class WifiManager : INetworkManager
{
    public void Connect() => System.Console.WriteLine("Connecting.");
    public void Send(byte[] file) => System.Console.WriteLine("Sending file.");
}

Usage

var digitalCamera = new DigitalCameraFacade(new DSLR(), new SDCardManager(), new WifiManager());
digitalCamera.TakePhoto();

Output

Taking photo.
Writing file from drive.
Sending file.

Comments

Post a Comment

Popular posts from this blog

Software Development

Software Development Agile Agile is an insurance policy for market changes. By designing your solution according to this methodology, your project remains flexible and is always ready for change. It is always better to correct the mistake early in the process. With this method, you keep your finger on the pulse of a dynamic market and changing user expectations. As a result, you can continuously adapt, change your strategy, and create a product that will be in demand by the target audience, even if preferences have changed during the development process. DevOps DevOps is one more way to optimize the development budget of your application. A key DevOps approach is that this practice and its culture allow team members to better interact with each other and the customer. The software development team and those responsible for the operation of the application share responsibilities clearly, and it helps you avoid shifting responsibilities from one team member to another. DevOps involves th...
Post a Comment
Read more

XML Webservice (ASMX) - SOAP Request and Response Invocation logging

You are an integration developer. Eventualy you came into the state where there is nothing else you can debug, and you have to check which SOAP request it is built on the request, and which SOAP response you are getting from the server. C# XML Webservice (ASMX) - SOAP Request and Response Invocation logging In the legaccy .NET framework System.Web.Services , this means using soapExtensions to help you intersept the interaction with the webservice. This is done like so:  public class TraceExtension : SoapExtension     {         Stream oldStream;         Stream newStream;         string filename;         // Save the Stream representing the SOAP request or SOAP response into          // a local memory buffer.          public override Stream ChainStream(Stream stream)         {           ...
Post a Comment
Read more

Abstract Factory Pattern

Abstract Factory Pattern  Gamma Categorization: Creational Design Patten Summary: When the object construction is complicated, needing multiple arguments, we should create a separate function (Factory Method) or class (Factory), which is responsible for the creation of the all object. Problem examples Suport of multiple databases Multiple data sources: Serial port, ethernet port, device driver Diferent report types Solution Abstract class Generalized interface A Factory creates instances of the concrete classes Sample Code The abstract factory public   interface   IPhotoFactory {      IAnaloguePhoto   CreateAnaloguePhoto ();      IDigitalPhoto   CreateDigitalPhoto (); } The abstract products public   interface   IAnaloguePhoto {      string   GetName (); } public   interface   IDigitalPhoto {      ...
Post a Comment
Read more