// Mediator pattern -- Real World example 


using System;
using System.Collections;

namespace DoFactory.GangOfFour.Mediator.RealWorld
{
 
 // MainApp test application 

 class MainApp
 {
  static void Main()
  {
   // Create chatroom 
   Chatroom chatroom = new Chatroom();

   // Create participants and register them 
   Participant George = new Beatle("George");
   Participant Paul = new Beatle("Paul");
   Participant Ringo = new Beatle("Ringo");
   Participant John = new Beatle("John") ;
   Participant Yoko = new NonBeatle("Yoko");

   chatroom.Register(George);
   chatroom.Register(Paul);
   chatroom.Register(Ringo);
   chatroom.Register(John);
   chatroom.Register(Yoko);

   // Chatting participants 
   Yoko.Send ("John", "Hi John!");
   Paul.Send ("Ringo", "All you need is love");
   Ringo.Send("George", "My sweet Lord");
   Paul.Send ("John", "Can't buy me love");
   John.Send ("Yoko", "My sweet love") ;

   // Wait for user 
   Console.Read();
  }
 }

 // "Mediator" 

 abstract class AbstractChatroom
 {
  public abstract void Register(Participant participant);
  public abstract void Send(
   string from, string to, string message);
 }

 // "ConcreteMediator" 

 class Chatroom : AbstractChatroom
 {
  private Hashtable participants = new Hashtable();

  public override void Register(Participant participant)
  {
   if (participants[participant.Name] == null)
   {
    participants[participant.Name] = participant;
   }

   participant.Chatroom = this;
  }

  public override void Send(
   string from, string to, string message)
  {
   Participant pto = (Participant)participants[to];
   if (pto != null)
   {
    pto.Receive(from, message);
   }
  }
 }

 // "AbstractColleague" 

 class Participant
 {
  private Chatroom chatroom;
  private string name;

  // Constructor 
  public Participant(string name)
  {
   this.name = name;
  }

  // Properties 
  public string Name
  {
   get{ return name; }
  }

  public Chatroom Chatroom
  {
   set{ chatroom = value; }
   get{ return chatroom; }
  }

  public void Send(string to, string message)
  {
   chatroom.Send(name, to, message);
  }

  public virtual void Receive(
   string from, string message)
  {
   Console.WriteLine("{0} to {1}: '{2}'",
    from, Name, message);
  }
 }

 //" ConcreteColleague1" 

 class Beatle : Participant
 {
  // Constructor 
  public Beatle(string name) : base(name) 
  { 
  }

  public override void Receive(string from, string message)
  {
   Console.Write("To a Beatle: ");
   base.Receive(from, message);
  }
 }

 //" ConcreteColleague2" 

 class NonBeatle : Participant
 {
  // Constructor 
  public NonBeatle(string name) : base(name) 
  { 
  }

  public override void Receive(string from, string message)
  {
   Console.Write("To a non-Beatle: ");
   base.Receive(from, message);
  }
 }
}