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