c#设计模式之中介类模式

定义一个中介对象来封装一系列对象之间的交互，使原有对象之间的耦合松散，且可以独立地改变它们之间的交互。中介者模式又叫调停模式，它是迪米特法则的典型应用

类图如下

Mediator

public abstract class Mediator
    {
        public abstract void Register(Colleague colleague);
        public abstract void Relay(Colleague colleague);
    }

ConcreteMediator

public class ConcreteMediator : Mediator
    {
        private List<Colleague> colleagues = new List<Colleague>();
        public override void Register(Colleague colleague)
        {
            if(!this.colleagues.Contains(colleague))
            {
                this.colleagues.Add(colleague);
                colleague.SetMediator(this);
            }
        }

        public override void Relay(Colleague colleague)
        {
            foreach (var item in this.colleagues.Where(p => p!= colleague))
            {
                item.Receive();
            }
        }
    }

Colleague

public abstract class Colleague
    {
        protected Mediator mediator;
        public void SetMediator(Mediator mediator)
        {
            this.mediator = mediator;
        }
        public abstract void Send();
        public abstract void Receive();
    }

ColleageA

 public class ColleageA : Colleague
    {
        public override void Receive()
        {
            Console.WriteLine("Receive in ColleageA");
        }

        public override void Send()
        {
            this.mediator.Relay(this);
        }
    }

ColleageB

public class ColleageB:Colleague
    {
        public override void Send()
        {
            this.mediator.Relay(this);
        }

        public override void Receive()
        {
            Console.WriteLine("Receive in ColleageB");
        }
    }

调用
···
static void Main(string[] args)
{
var mediator = new ConcreteMediator();

        ColleageA colleageA = new ColleageA();
        ColleageB colleageB = new ColleageB();
        mediator.Register(colleageA);
        mediator.Register(colleageB);

        colleageA.Send();
    }

···

优点：

1. 降低了对象的耦合，使同事类之间不在相互依赖，符合单一职责

缺点：

1. 当同事类比较多时，中介类职责会变得越来越庞大

源代码地址： 点击我下载 提取码: x284