Pattern: Chain of Responsibility

The Chain of Responsibility pattern is used to pass a request along a chain of handlers. Each handler decides either to process the request or to pass it to the next handler in the chain. Here's a simple example of the Chain of Responsibility pattern in C#:

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using System; // Handler interface public interface IHandler { IHandler SetNext(IHandler handler); string HandleRequest(int request); } // ConcreteHandler class public class ConcreteHandler : IHandler { private IHandler _nextHandler; public IHandler SetNext(IHandler handler) { _nextHandler = handler; return handler; } public string HandleRequest(int request) { if (request >= 0 && request < 10) { return $"Handler 1: {request}"; } else if (_nextHandler != null) { return _nextHandler.HandleRequest(request); } else { return "No handler can process the request."; } } } class Program { static void Main() { // Create the chain of handlers IHandler handler1 = new ConcreteHandler(); IHandler handler2 = new ConcreteHandler(); IHandler handler3 = new ConcreteHandler(); handler1.SetNext(handler2).SetNext(handler3); // Process requests Console.WriteLine(handler1.HandleRequest(5)); Console.WriteLine(handler1.HandleRequest(15)); } }

In this example:

- IHandler is the handler interface, defining the `SetNext` method to set the next handler and the `HandleRequest` method to process the request.

- ConcreteHandler is a concrete handler class implementing the `IHandler` interface. It processes requests in a specific range and passes the request to the next handler if applicable.

The Main method creates a chain of handlers and processes requests. This is a simplified example, and in a real-world scenario, handlers might be more complex, and the chain may be dynamically constructed.