设计模式-外观模式

适用情境:对客户端屏蔽各个子系统的细节,使用户可以用统一的接口使用子系统.

// subsystema.h
#ifndef SUBSYSTEMA_H
#define SUBSYSTEMA_H

class SubSystemA
{
public:
    SubSystemA();
    void MethodA();
};

#endif // SUBSYSTEMA_H

// subsystema.cpp
#include "subsystema.h"
#include <iostream>

SubSystemA::SubSystemA()
{}

void SubSystemA::MethodA()
{
    std::cout << "MethodA..." << std::endl;
}

// subsystemb.h
#ifndef SUBSYSTEMB_H
#define SUBSYSTEMB_H

class SubSystemB
{
public:
    SubSystemB();
    void MethodB();
};

#endif // SUBSYSTEMB_H

// subsystemb.cpp
#include "subsystemb.h"
#include <iostream>

SubSystemB::SubSystemB()
{}

void SubSystemB::MethodB()
{
    std::cout << "MethodB..." << std::endl;
}

// facade.h
#ifndef FACADE_H
#define FACADE_H

#include "subsystema.h"
#include "subsystemb.h"

class Facade
{
public:
    Facade();
    ~Facade();
    void FacadeMethod();
private:
    SubSystemA *m_subsysA;
    SubSystemB *m_subsysB;
};

#endif // FACADE_H

// facade.cpp
#include "facade.h"

Facade::Facade()
{
    m_subsysA = new SubSystemA();
    m_subsysB = new SubSystemB();
}

Facade::~Facade()
{
    delete m_subsysA;
    delete m_subsysB;
}

void Facade::FacadeMethod()
{
    m_subsysA->MethodA();
    m_subsysB->MethodB();
}

客户端:

// main.cpp
#include <iostream>

#include "facade.h"

using namespace std;

int main(int argc, char *argv[])
{
    Facade *facade = new Facade();
    facade->FacadeMethod();
    return 0;
}