·23种设计模式学习—Factory模式

 Factory 模式的两个最重要的功能:

1)定义创建对象的接口,封装了对象的创建;

2)使得具体化类的工作延迟到了子类中。

/* author: FiveWei */
/* time:2012.12.04 */
/* filename:Car.h */


#ifndef _CAR_H
#define _CAR_H


#include <cstdio>

class Car
{
public:
     virtual void info() = 0 ;
} ;

class Ford : public Car
{
public:
     virtual void info()
     {
          printf( "Ford\n" ) ;
     }
} ;

class Toyota : public Car
{
public:
     virtual void info()
     {
          printf( "Toyota\n" ) ;
     }
} ;

#endif

/* author: FiveWei */
/* time:2012.12.04 */
/* filename:CarFactory.h */

#ifndef _CARFACTORY_H
#define _CARFACTORY_H

#include "Car.h"

class CarFactory
{
public:
     CarFactory() ;
     Car* requestCar() ;
     int getCarNums() const ;

protected:
     virtual Car* createCar() = 0 ;

private:
     int CarNums ;
} ;

class FordFactory : public CarFactory
{
protected:
     virtual Car* createCar() ;
} ;

class ToyotaFactory : public CarFactory
{
protected :
     virtual Car* createCar() ;
} ;

#endif

/* author: FiveWei */
/* time:2012.12.04 */
/* filename:CarFactory.cpp */


#ifndef _CARFACTORY_CPP
#define _CARfACTORY_CPP


#include "CarFactory.h"

#include <cstdio>

CarFactory::CarFactory() : CarNums(0) {}

Car* CarFactory::requestCar() {
    CarNums ++ ;
    return createCar() ;
}

int CarFactory::getCarNums() const
{
    return CarNums ;
}

Car* FordFactory::createCar()
{
    return new Ford() ;
}

Car* ToyotaFactory::createCar()
{
    return new Toyota() ;
}

#endif

/* author: FiveWei */
/* time:2012.12.04 */
/* filename:TestFactory.cpp */

#include <vector>
#include "CarFactory.h"

#include <cstdio>
using namespace std ;

CarFactory* getBest( const vector<CarFactory*>& inFacs ) //找到最闲的工厂
{
    size_t Size = inFacs.size() ;
    if ( Size == 0 ) return NULL ;

    CarFactory* best = inFacs[0] ;
    for ( size_t i = 0 ; i < Size ; i++ )
    {
        if ( best->getCarNums() > inFacs[i]->getCarNums() )
            best = inFacs[i] ;
    }
    return best ;
}

int main()
{
    vector<CarFactory*> factories ;

    FordFactory* factory1 = new FordFactory() ;
    FordFactory* factory2 = new FordFactory() ;
    FordFactory* factory3 = new FordFactory() ;
    ToyotaFactory* factory4 = new ToyotaFactory() ;

    factories.push_back( factory1 ) ;
    factories.push_back( factory2 ) ;
    factories.push_back( factory3 ) ;
    factories.push_back( factory4 ) ;

    for ( int i = 0 ; i < 10  ; i++ )
    {
        // request the least busy factory from the 4 factories
        CarFactory* CurFac = getBest( factories ) ;
        Car* theCar = CurFac->requestCar() ;
        theCar->info() ;
    }

    return 0 ;
}