====== Facade 패턴 ======

===== 타입 =====
Structural Pattern

===== 문제 =====
클래스가 많고 인터페이스가 복잡하다.

===== 해결 =====
여러 개의 클래스 또는 인터페이스를 순차적으로 호출하는 클래스를 만든다.

===== 클래스 다이어그램 =====
{{:programming:design_pattern:facade.png|}}

===== 예제 =====

<file cpp facade.cpp>
/*Facade is one of the easiest patterns I think... And this is very simple example. 
  
Imagine you set up a smart house where everything is on remote. So to turn the lights on you push lights on button - And same for TV,
AC, Alarm, Music, etc...
  
When you leave a house you would need to push a 100 buttons to make sure everything is off and are good to go which could be little 
annoying if you are lazy like me 
so I defined a Facade for leaving and coming back. (Facade functions represent buttons...) So when I come and leave I just make one 
call and it takes care of everything...
  
*/
  
#include <string>
#include <iostream>
  
using namespace std;
  
class Alarm
{
public:
    void alarmOn()
    {
        cout<<"Alarm is on and house is secured"<<endl;
    }
  
    void alarmOff()
    {
        cout<<"Alarm is off and you can go into the house"<<endl;
    }
};
  
class Ac
{
public:
    void acOn()
    {
        cout<<"Ac is on"<<endl;
    }
  
    void acOff()
    {
        cout<<"AC is off"<<endl;
    }
};
  
class Tv
{
public:
    void tvOn()
    {
        cout<<"Tv is on"<<endl;
    }
  
    void tvOff()
    {
        cout<<"TV is off"<<endl;
    }
  
  
};
  
class HouseFacade
{
    Alarm alarm;
    Ac ac;
    Tv tv;
  
public:
  
    HouseFacade(){}
  
    void goToWork()
    {
        ac.acOff();
        tv.tvOff();
        alarm.alarmOn();
    }
  
    void comeHome()
    {
        alarm.alarmOff();
        ac.acOn();
        tv.tvOn();
    }
  
};
  
int main()
{
   HouseFacade hf;
  
   //Rather than calling 100 different on and off functions thanks to facade I only have 2 functions...
   hf.goToWork();
   hf.comeHome();
}
</file>

===== 참고 =====
http://en.wikibooks.org/wiki/C%2B%2B_Programming/Code/Design_Patterns#Facade