读书笔记18：命令模式

1、定义：

将一个请求封装为一个对象，从而使你可用不同的请求对客户进行参数化；对请求排队或记录请求日志，以及支持可撤消的操作。[GOF 《设计模式》]

2、角色

Command——用来执行操作的接口。

CreateCommand——将一个接收者对象绑定一个动作，并实现执行命令操作。

Invoker——要求该命令执行。

Receiver——知道如何实施与执行一个与请求相关的操作，任何类都可作为一个接收者。

3、模型

Command

abstract class Command
{
protected Receiver receiver;
public Command(Receiver creceiver)
{
this.receiver = creceiver;
}

abstract public void Execute();
}

CreateCommand

class CreateCommand : Command
{
public CreateCommand(Receiver receiver)

: base(receiver)
{

}

public override void Execute()
{
receiver.Action();
}
}

Receiver

class Receiver
{
public void Action()
{
Console.WriteLine("执行命令");
}
}

Invoker

class Invoker
{
private Command command;

public void SetCommand(Command command)
{
this.command = command;
}

public void ExecuteCommand()
{
command.Execute();
}
}

调用

static void Main(string[] args)
{
Receiver receiver = new Receiver();

Command command = new CreateCommand(receiver);

Invoker invoker = new Invoker();

invoker.SetCommand(command);

invoker.ExecuteCommand();

Console.ReadLine();
}

结果：



命令模式模型代码：http://download.csdn.net/detail/yysyangyangyangshan/4089536

命令模式，很多个Receiver，并与之对应Command也有很多个，Invoker则负责将Receiver和Command关联，并执行。

应用模型：

abstract class Command1
{
protected Receiver1 receiver1;

public Command1(Receiver1 creceiver1)
{
this.receiver1 = creceiver1;
}

abstract public void Execute();
}

abstract class Command2
{
protected Receiver2 receiver2;

public Command2(Receiver2 creceiver2)
{
this.receiver2 = creceiver2;
}

abstract public void Execute();
}
class CreateCommand1 : Command1
{
public CreateCommand1(Receiver1 receiver1)

: base(receiver1)
{

}

public override void Execute()
{
receiver1.Action();
}
}
class CreateCommand2 : Command2
{
public CreateCommand2(Receiver2 receiver2)

: base(receiver2)
{

}

public override void Execute()
{
receiver2.Action();
}
}
class Invoker
{
private Command1 command1;

private Command2 command2;

public void SetCommand1(Command1 command)
{
this.command1 = command;
}

public void ExecuteCommand1()
{
command1.Execute();
}

public void SetCommand2(Command2 command)
{
this.command2 = command;
}

public void ExecuteCommand2()
{
command2.Execute();
}
}
class Receiver1
{
public void Action()
{
Console.WriteLine("执行命令一");
}
}
class Receiver2
{
public void Action()
{
Console.WriteLine("执行命令二");
}
}

调用

static void Main(string[] args)
{
Receiver1 receiver1 = new Receiver1();

Receiver2 receiver2 = new Receiver2();

Command1 command1 = new CreateCommand1(receiver1);

Command2 command2 = new CreateCommand2(receiver2);

Invoker invoker = new Invoker();

invoker.SetCommand1(command1);

invoker.ExecuteCommand1();

invoker.SetCommand2(command2);

invoker.ExecuteCommand2();

Console.ReadLine();
}

结果：



应用代码：http://download.csdn.net/detail/yysyangyangyangshan/4089547