CODESAMPLE

Proxy - C#

Proxy C_sharp

The Proxy pattern provides a surrogate or placeholder for another object to control access to it. This is useful for scenarios like remote access, security checks, or lazy initialization. The Subject interface defines the common interface for both the real object (RealSubject) and the proxy (Proxy). The Proxy controls access to the RealSubject, potentially adding functionality before or after the real object’s method is called. This C# implementation uses interfaces to define the contract, which is a common and preferred approach in C# for loose coupling and testability. The proxy handles the creation of the real subject only when needed.

// Define the common interface for the real object and the proxy
public interface ISubject
{
    void Request();
}

// The real object
public class RealSubject : ISubject
{
    public void Request()
    {
        Console.WriteLine("RealSubject: Handling request.");
    }
}

// The proxy
public class Proxy : ISubject
{
    private ISubject? _realSubject;

    public void Request()
    {
        if (_realSubject == null)
        {
            Console.WriteLine("Proxy: Initializing RealSubject.");
            _realSubject = new RealSubject();
        }

        Console.WriteLine("Proxy: Logging request before forwarding.");
        _realSubject.Request();
        Console.WriteLine("Proxy: Logging request after forwarding.");
    }
}

// Client code
public class Client
{
    public static void Main(string[] args)
    {
        Proxy proxy = new Proxy();
        proxy.Request();
        proxy.Request(); // Demonstrates lazy initialization
    }
}