Mediator 1

using System.Collections.Generic;

namespace CA01 {
    public interface IMediator<T> {
        List<ICollaborator<T>> CollaboratorList { get; }
        void DistributeMessage(ICollaborator<T> sender, string message);
        void Register(ICollaborator<T> collaborator);

    }
}

namespace CA01 {
    public interface ICollaborator<T> {
        void SendMessage(IMediator<T> mediator, string message);

        void ReceiveMessage(string message);
    }
}

using System;

namespace CA01 {
    public sealed class NewsStation<T> : ICollaborator<T> {

        public string Name { get; private set; }

        public NewsStation(string name) {
            Name = name;
        }
        void ICollaborator<T>.SendMessage(IMediator<T> mediator, string message) {
            mediator.DistributeMessage(this, message);
        }
        void ICollaborator<T>.ReceiveMessage(string message) {
            Console.WriteLine("\n" + Name + " received \n" + message.ToString());
        }
    }
}
using System.Collections.Generic;

namespace CA01 {

    /// <summary>
    /// Singleton class to implement a (concrete) mediator. The _instance and the private constructor are used
    /// for this. All other objects and methods cover the functional side
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public sealed class ConcreteMediator<T> : IMediator<T> {

        // Singleton techniques...
        private static readonly ConcreteMediator<T> _instance = new ConcreteMediator<T>();

        private ConcreteMediator() { }

        public static ConcreteMediator<T> GetInstance() {
            return _instance;
        }

        private List<ICollaborator<T>> colleagueList = new List<ICollaborator<T>>();

        List<ICollaborator<T>> IMediator<T>.CollaboratorList {
            get { return colleagueList; }
        }

        void IMediator<T>.Register(ICollaborator<T> colleague) {
            colleagueList.Add(colleague);
        }

        void IMediator<T>.DistributeMessage(ICollaborator<T> sender, string message) {
            foreach (var c in colleagueList) {
                if (c != sender) {
                    c.ReceiveMessage(message);
                }
            }
        }
    }

}


using System;

namespace CA01 {
    public class Program {

        public static void Main() {
            var p = new Program();
            p.RunTheTest();
        }
        public void RunTheTest() {

            ICollaborator<string> BBCRadioLeicester = new NewsStation<string>("BBCRadioLeicester");
            ICollaborator<string> CapitalRadio = new NewsStation<string>("CapitalRadio");
            ICollaborator<string> LBC = new NewsStation<string>("LBC");

            IMediator<string> mediator = ConcreteMediator<string>.GetInstance();
            mediator.Register(BBCRadioLeicester);
            mediator.Register(CapitalRadio);
            mediator.Register(LBC);

            BBCRadioLeicester.SendMessage(mediator, "[A cat has been found] broadcast from [BBCRadioLeicester]");
            CapitalRadio.SendMessage(mediator, "[Price of Stuff has increased] broadcast from [CapitalRadio]");

            Console.WriteLine("That's all for now - press return twice");
            Console.Read();
        }
    }

}