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

posted on 2012-02-25 16:35 c语言源码阅读(146) 评论(0) 编辑收藏举报

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