命令模式

在软件系统中，“行为请求者”与“行为实现者”通常呈现一种“紧耦合”。但在某些场合，比如要对行为进行“记录、撤销/重做、事务”等处理，这种无法抵御变化的紧耦合是不合适的。在这种情况下，如何将“行为请求者”与“行为实现者”解耦？将一组行为抽象为对象，实现二者之间的松耦合。这就是命令模式（Command Pattern）

Command：

#ifndef CommandH
#define CommandH
#include "CAbstractReciver.h"
class command
{
public:
      virtual ~command(){};
      virtual void exec()=0;
      void SetReciver(CAbstractReciver *tCAbstractReciver){pCAbstractReciver = tCAbstractReciver;};
protected: 
      command(){};
      CAbstractReciver *pCAbstractReciver;
};
#endif

#ifndef ConcreateCommandH
#define ConcreateCommandH
#include "command.h"
class ConcreateCommand:public command
{
public:
       ~ConcreateCommand(){};
       ConcreateCommand(){};
       void exec(){pCAbstractReciver->Action();};
};
#endif

Receiver：

#ifndef CAbstractReciverH
#define CAbstractReciverH
#include <iostream>
using namespace std;
class CAbstractReciver
{
public:
       virtual ~CAbstractReciver(){};
       virtual void Action() = 0;
protected:
       CAbstractReciver(){};
                                               
};
#endif
#ifndef CReciverAH
#define CReciverAH
#include "CAbstractReciver.h"
class CReciverA:public CAbstractReciver
{
public:
      CReciverA(){};
      ~CReciverA(){};
      void Action(){cout<<"我打开了电视机"<<endl; };
                                               
};
#endif
#ifndef CReciverBH
#define CReciverBH
#include "CAbstractReciver.h"
class CReciverB:public CAbstractReciver
{
public:
      CReciverB(){};
      ~CReciverB(){};
      void Action(){cout<<"我打开了空调"<<endl; };
                                               
};
#endif

Invoker：

#ifndef CInvokerH
#define CInvokerH
#include "command.h"
class CInvoker
{
public:
      CInvoker(){};
      ~CInvoker(){};
      void exec(command *pcommand){pcommand->exec();};
                                      
};
#endif

Client：

#include "CAbstractReciver.h"
#include "ConcreateCommand.h"
#include "CReciverA.h"
#include "CReciverB.h"
#include "CInvoker.h"
int main()
{
  CInvoker tCInvoker;
  ConcreateCommand *pConcreateCommand = new ConcreateCommand();
                           
  CReciverA *pCReciverA = new CReciverA();
  pConcreateCommand->SetReciver(pCReciverA);
                           
  tCInvoker.exec(pConcreateCommand);
                           
  CReciverB *pCReciverB = new CReciverB();
  pConcreateCommand->SetReciver(pCReciverB);
  tCInvoker.exec(pConcreateCommand);
  return 0;
}

makefile

aLL:Command
CC = g++
INCLUDE = .
CFLAGS = -g -Wall
Command:main.o CReciverA.o CReciverB.o ConcreateCommand.o CInvoker.o
    $(CC) -o Command main.o CReciverA.o CReciverB.o ConcreateCommand.o CInvoker.o
CReciverA.o:CReciverA.cpp CReciverA.h
    $(CC) -I$(INCLUDE) $(CFLAGS) -c CReciverA.cpp
CReciverB.o:CReciverB.cpp CReciverB.h
    $(CC) -I$(INCLUDE) $(CFLAGS) -c CReciverB.cpp
ConcreateCommand.o:ConcreateCommand.cpp ConcreateCommand.h
    $(CC) -I$(INCLUDE) $(CFLAGS) -c ConcreateCommand.cpp
CInvoker.o:CInvoker.cpp CInvoker.h
    $(CC) -I$(INCLUDE) $(CFLAGS) -c CInvoker.cpp
main.o:main.cpp
    $(CC) -I$(INCLUDE) $(CFLAGS) -c main.cpp
clean:
    rm *.o
    rm Command

result

administrator@ubuntu:~/桌面/Java/DesignMode/Command$ make -f makefile
g++ -I. -g -Wall  -c main.cpp
g++ -I. -g -Wall  -c CReciverA.cpp
g++ -I. -g -Wall  -c CReciverB.cpp
g++ -I. -g -Wall  -c ConcreateCommand.cpp
g++ -I. -g -Wall  -c CInvoker.cpp
g++ -o Command main.o CReciverA.o CReciverB.o ConcreateCommand.o CInvoker.o
administrator@ubuntu:~/桌面/Java/DesignMode/Command$ ./Command
我打开了电视机
我打开了空调
administrator@ubuntu:~/桌面/Java/DesignMode/Command$

本文出自 “风清扬song” 博客，请务必保留此出处http://2309998.blog.51cto.com/2299998/1394602

命令模式,布布扣,bubuko.com

命令模式

原文：http://2309998.blog.51cto.com/2299998/1394602