// Chain of Responsibility pattern -- Real World example
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using System;
namespace DoFactory.GangOfFour.Chain.RealWorld { // MainApp test application class MainApp { static void Main() { // Setup Chain of Responsibility Director Larry = new Director(); VicePresident Sam = new VicePresident(); President Tammy = new President(); Larry.SetSuccessor(Sam); Sam.SetSuccessor(Tammy); // Generate and process purchase requests Purchase p = new Purchase(2034, 350.00, "Supplies"); Larry.ProcessRequest(p); p = new Purchase(2035, 32590.10, "Project X"); Larry.ProcessRequest(p); p = new Purchase(2036, 122100.00, "Project Y"); Larry.ProcessRequest(p); // Wait for user Console.Read(); } } // "Handler" abstract class Approver { protected Approver successor; public void SetSuccessor(Approver successor) { this.successor = successor; } public abstract void ProcessRequest(Purchase purchase); } // "ConcreteHandler" class Director : Approver { public override void ProcessRequest(Purchase purchase) { if (purchase.Amount < 10000.0) { Console.WriteLine("{0} approved request# {1}", this.GetType().Name, purchase.Number); } else if (successor != null) { successor.ProcessRequest(purchase); } } } // "ConcreteHandler" class VicePresident : Approver { public override void ProcessRequest(Purchase purchase) { if (purchase.Amount < 25000.0) { Console.WriteLine("{0} approved request# {1}", this.GetType().Name, purchase.Number); } else if (successor != null) { successor.ProcessRequest(purchase); } } } // "ConcreteHandler" class President : Approver { public override void ProcessRequest(Purchase purchase) { if (purchase.Amount < 100000.0) { Console.WriteLine("{0} approved request# {1}", this.GetType().Name, purchase.Number); } else { Console.WriteLine( "Request# {0} requires an executive meeting!", purchase.Number); } } } // Request details class Purchase { private int number; private double amount; private string purpose; // Constructor public Purchase(int number, double amount, string purpose) { this.number = number; this.amount = amount; this.purpose = purpose; } // Properties public double Amount { get{ return amount; } set{ amount = value; } } public string Purpose { get{ return purpose; } set{ purpose = value; } } public int Number { get{ return number; } set{ number = value; } } } } |
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