23种设计模式C++实例之外观模式

#include <iostream>

using namespace std;

/*
* 外观模式:将子系统中的一组接口提供一个一致的界面
* 外观模式定义了一个高层接口，这个接口使得这一子系统更加容易使用
* */

class SubsysA {
public:
void dothing() {
cout << "SubsysA do thing" << endl;
}
};

class SubsysB {
public:
void dothing() {
cout << "SubsysB do thing" << endl;
}
};

class SubsysC {
public:
void dothing() {
cout << "SubsysC do thing" << endl;
}
};

class Facade {
public:
Facade() {
m_sysA = new SubsysA;
m_sysB = new SubsysB;
m_sysC = new SubsysC;
}
~Facade() {
if (m_sysA != NULL) {
delete m_sysA;
m_sysA = NULL;
}
if (m_sysB != NULL) {
delete m_sysB;
m_sysB = NULL;
}
if (m_sysC != NULL) {
delete m_sysC;
m_sysC = NULL;
}
}
void dothing() {
m_sysA->dothing();
m_sysB->dothing();
m_sysC->dothing();
}
private:
SubsysA* m_sysA;
SubsysB* m_sysB;
SubsysC* m_sysC;
};

int main() {
// 使用外观模式之前
SubsysA* a = new SubsysA;
a->dothing();
delete a;

SubsysB* b = new SubsysB;
b->dothing();
delete b;

SubsysC* c = new SubsysC;
c->dothing();
delete c;

cout << endl;

// 使用外观模式之前
Facade* facade = new Facade;
facade->dothing();
delete facade;

return 0;
}