定义定义一个对象，封装对象集之间的交互。该模式通过阻止对象间显示引用从而减少对象间的耦合，同时它允许独立的改变他们之间的交互。
使用频度:
![]()
中低
UML 类图![]()
参与者该模式参与的类或对象
- 在需要与其他同事通信时，不管什么时候，每个同事均与其调停者通信
C# 示例代码
// Mediator pattern -- Structural example
using System;
namespace DoFactory.GangOfFour.Mediator.Structural
{
///
/// MainApp startup class for Structural
/// Mediator Design Pattern.
///
class MainApp
{
///
/// Entry point into console application.
///
static void Main()
{
ConcreteMediator m = new ConcreteMediator();
ConcreteColleague1 c1 = new ConcreteColleague1(m);
ConcreteColleague2 c2 = new ConcreteColleague2(m);
m.Colleague1 = c1;
m.Colleague2 = c2;
c1.Send("How are you?");
c2.Send("Fine, thanks");
// Wait for user
Console.ReadKey();
}
}
///
/// The 'Mediator' abstract class
///
abstract class Mediator
{
public abstract void Send(string message,
Colleague colleague);
}
///
/// The 'ConcreteMediator' class
///
class ConcreteMediator : Mediator
{
private ConcreteColleague1 _colleague1;
private ConcreteColleague2 _colleague2;
public ConcreteColleague1 Colleague1
{
set { _colleague1 = value; }
}
public ConcreteColleague2 Colleague2
{
set { _colleague2 = value; }
}
public override void Send(string message,
Colleague colleague)
{
if (colleague == _colleague1)
{
_colleague2.Notify(message);
}
else
{
_colleague1.Notify(message);
}
}
}
///
/// The 'Colleague' abstract class
///
abstract class Colleague
{
protected Mediator mediator;
// Constructor
public Colleague(Mediator mediator)
{
this.mediator = mediator;
}
}
///
/// A 'ConcreteColleague' class
///
class ConcreteColleague1 : Colleague
{
// Constructor
public ConcreteColleague1(Mediator mediator)
: base(mediator)
{
}
public void Send(string message)
{
mediator.Send(message, this);
}
public void Notify(string message)
{
Console.WriteLine("Colleague1 gets message: "
+ message);
}
}
///
/// A 'ConcreteColleague' class
///
class ConcreteColleague2 : Colleague
{
// Constructor
public ConcreteColleague2(Mediator mediator)
: base(mediator)
{
}
public void Send(string message)
{
mediator.Send(message, this);
}
public void Notify(string message)
{
Console.WriteLine("Colleague2 gets message: "
+ message);
}
}
}
|
输出
Colleague2 gets message: How are you?
Colleague1 gets message: Fine, thanks
|
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