命令模式(Command)

最新推荐文章于 2024-11-12 16:40:55 发布

xufei96

最新推荐文章于 2024-11-12 16:40:55 发布

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分类专栏：设计模式笔记文章标签： command string class kill

本文链接：https://blog.youkuaiyun.com/xufei96/article/details/5419974

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本文介绍了命令模式的设计原理，通过UML类图展示了各部分之间的关系，并提供了C#与Python两种语言的具体实现代码。该模式中，Invoker负责维护Command，而Command又进一步维护CommandTarget，实现了请求的封装。

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个人理解：

Invoker维护Command Command维护CommandTarget

UML类图

代码实现

    public interface ICommand
    {
        void Execute();
    }

    public class Invoker
    {
        private ICommand command;

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

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

    public class PrintCommand:ICommand
    {
        public CommandTarget target;

        public PrintCommand(CommandTarget target)
        {
            this.target = target;
        }

        public void Execute()
        {
            target.Action();
        }
    }

    public class CommandTarget
    {
        public void Action()
        {
            Console.WriteLine("HAHA...The 18th model in 23...Fuck...Bitch...Shit...");
        }
    }

Python代码实现

class CommandTarget(object):
    name=''

class Dog(CommandTarget):
    pass

class Cat(CommandTarget):
    pass

class Command(object):
    def Execute(self):
        raise NotImplementedError("abstract class")

class RunCommand(Command):
    commandTarget=None
    def __init__(self, commandTarget):
        self.commandTarget=commandTarget
    def Execute(self):
        print self.commandTarget.Name + " is running."

class SitCommand(Command):
    commandTarget=None
    def __init__(self, commandTarget):
        self.commandTarget=commandTarget
    def Execute(self):
        print self.commandTarget.Name + " is sitting."

class CommandHandler(object):
    command=None
    def __init__(self, command):
        self.command=command
    def ExecuteCommand(self):
        self.command.Execute()
    def SetCommand(self, command):
        self.command=command

if __name__ == "__main__":
    dog=Dog()
    dog.Name="dog tom"

    cat=Cat()
    cat.Name="cat jerry"

    sitCommand=SitCommand(cat)
    handler=CommandHandler(sitCommand)
    handler.ExecuteCommand()

    runCommand=RunCommand(dog)
    handler.SetCommand(runCommand)
    handler.ExecuteCommand()