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命令模式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,另外对请求排队或记录请求日志,以及支持可撤销的操作。
namespace 命令模式 { class Program { static void Main(string[] args) { //开店前的准备 Barbecuer boy = new Barbecuer(); Command bakeMuttonCommand1 = new BakeMuttonCommand(boy); Command bakeMuttonCommand2 = new BakeMuttonCommand(boy); Command bakeChickenWingCommand1 = new BakeChickenWingCommand(boy); Waiter girl = new Waiter(); //开门营业 顾客点菜 girl.SetOrder(bakeMuttonCommand1); girl.SetOrder(bakeMuttonCommand2); girl.SetOrder(bakeChickenWingCommand1); //点菜完闭,通知厨房 girl.Notify(); Console.Read(); } } //服务员 public class Waiter { private IList<Command> orders = new List<Command>(); //设置订单 public void SetOrder(Command command) { if (command.ToString() == "命令模式.BakeChickenWingCommand") { Console.WriteLine("服务员:鸡翅没有了,请点别的烧烤。"); } else { orders.Add(command); Console.WriteLine("增加订单:" + command.ToString() + " 时间:" + DateTime.Now.ToString()); } } //取消订单 public void CancelOrder(Command command) { orders.Remove(command); Console.WriteLine("取消订单:" + command.ToString() + " 时间:" + DateTime.Now.ToString()); } //通知全部执行 public void Notify() { foreach (Command cmd in orders) { cmd.ExcuteCommand(); } } } //抽象命令 public abstract class Command { protected Barbecuer receiver; public Command(Barbecuer receiver) { this.receiver = receiver; } //执行命令 abstract public void ExcuteCommand(); } //烤羊肉串命令 class BakeMuttonCommand : Command { public BakeMuttonCommand(Barbecuer receiver) : base(receiver) { } public override void ExcuteCommand() { receiver.BakeMutton(); } } //烤鸡翅命令 class BakeChickenWingCommand : Command { public BakeChickenWingCommand(Barbecuer receiver) : base(receiver) { } public override void ExcuteCommand() { receiver.BakeChickenWing(); } } //烤肉串者 public class Barbecuer { public void BakeMutton() { Console.WriteLine("烤羊肉串!"); } public void BakeChickenWing() { Console.WriteLine("烤鸡翅!"); } } }
命令模式优点:
第一,它比较容易设计一个命令队列。
第二,在需要的情况下,可以将命令进入日志。
第三,允许接收请求的一方决定是否否决请求。
第四,比较容易地实现对请求的撤销和重做。
第五,因为新的具体请求命令类和其他命令类互不影响,因此新增的具体命令类很容易。
最大的优点是命令模式把一个请求操作对象和知道怎么执行这个操作的对象分隔开。
namespace 命令模式 { class Program { static void Main(string[] args) { Receiver r = new Receiver(); Command c = new ConcreteCommand(r); Invoker i = new Invoker(); // Set and execute command i.SetCommand(c); i.ExecuteCommand(); Console.Read(); } } abstract class Command { protected Receiver receiver; public Command(Receiver receiver) { this.receiver = receiver; } abstract public void Execute(); } class ConcreteCommand : Command { public ConcreteCommand(Receiver receiver) : base(receiver) { } public override void Execute() { receiver.Action(); } } class Receiver { public void Action() { Console.WriteLine("执行请求!"); } } class Invoker { private Command command; public void SetCommand(Command command) { this.command = command; } public void ExecuteCommand() { command.Execute(); } } }
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原文地址:http://www.cnblogs.com/kesimin/p/4842522.html