Factory模式

1,简单工厂模式:
实例代码:

#include <iostream>
#include <list>
#include <cassert>
#include <sstream>
#include <memory>
using namespace std;

/************************产品基类******************************/
class Pizza
{
protected:
    Pizza() {}
public:
    virtual ~Pizza() = 0;
	string getName() const
	{
		return _name;
	}
	virtual void prepare() const
	{
		cout << "Preparing " << _name.c_str() << endl;
	}
	virtual void bake() const
	{
		cout << "Baking " << _name.c_str() << endl;
	}
	virtual void cut() const
	{
		cout << "Cutting " << _name.c_str() << endl;
	}
	public: virtual void box() const
	{
		cout << "Boxing " << _name.c_str() << endl;
	}
	string toString() const
	{
		// code to display pizza name and ingredients
		stringstream value;
		value << "---- " << _name.c_str() << " ----" << endl;
		value << _dough.c_str() << endl;
		value << _sauce.c_str() << endl;
		for( list< string >::iterator iterator = _toppings.begin(); _toppings.end() != iterator; ++iterator )
		{
			value << iterator->c_str() << endl;
		}
		return value.str();
	}
private:
    Pizza( const Pizza& ); // Disable copy constructor
	void operator=( const Pizza& ); // Disable assignment operator
protected:
    string _name;
	string _dough;
	string _sauce;
	mutable list<string> _toppings;
};

Pizza::~Pizza() {}

/************************产品类******************************/
class VeggiePizza : public Pizza
{
public:
    VeggiePizza()
    {
		_name = "Veggie Pizza";
		_dough = "Crust";
		_sauce = "Marinara Sauce";
		_toppings.push_back( "Fresh Mozzarella" );
		_toppings.push_back( "Grated Parmesan" );
		_toppings.push_back( "Diced onion" );
		_toppings.push_back( "Sliced mushrooms" );
		_toppings.push_back( "Sliced red pepper" );
		_toppings.push_back( "Sliced black olives" );
	}
};

class CheesePizza : public Pizza
{
public:
    CheesePizza()
    {
		_name = "Cheese Pizza";
		_dough = "Regular Crust";
		_sauce = "Marinara Pizza Sauce";
		_toppings.push_back( "Shredded Mozzarella" );
		_toppings.push_back( "Parmesan" );
	}
};

class ClamPizza : public Pizza
{
public:
    ClamPizza()
    {
		_name = "Clam Pizza";
		_dough = "Thin Crust";
		_sauce = "White garlic Sauce";
		_toppings.push_back( "Grated parmesan cheese" );
		_toppings.push_back( "Clams" );
	}
};

class PepperoniPizza : public Pizza
{
public:
    PepperoniPizza()
    {
		_name = "Pepperoni Pizza";
		_dough = "Crust";
		_sauce = "Marinara sauce";
		_toppings.push_back( "Sliced Pepperoni" );
		_toppings.push_back( "Sliced Onion" );
		_toppings.push_back( "Grated parmesan cheese" );
	}
};
/************************工厂类******************************/
class SimplePizzaFactory
{
public:
    Pizza* createPizza( std::string type ) const
    {
		Pizza* pizza = 0;
		if( type.compare( "cheese" ) == 0 )
		{
			pizza = new CheesePizza();
		}
		else if( type.compare( "pepperoni" ) == 0 )
		{
			pizza = new PepperoniPizza();
		}
		else if( type.compare( "clam" ) == 0 )
		{
			pizza = new ClamPizza();
		}
		else if( type.compare( "veggie" ) == 0 )
		{
			pizza = new VeggiePizza();
		}
		return pizza;
	}
};

/***********************管理类**********************************/
class PizzaStore
{
private:
    SimplePizzaFactory* _factory;
public:
    explicit PizzaStore( SimplePizzaFactory* factory ) :
		_factory( factory )
    {
        assert( factory );
	}
	public: Pizza* orderPizza( string type )
	{
		Pizza* pizza;
		pizza = _factory->createPizza( type );
		pizza->prepare();
		pizza->bake();
		pizza->cut();
		pizza->box();
		return pizza;
	}
};
int main()
{
    SimplePizzaFactory factory;
	PizzaStore store( &factory );

	auto_ptr< Pizza> pizza( store.orderPizza( "cheese" ) );
	cout << "We ordered a " << pizza->getName() << std::endl;

	pizza = auto_ptr< Pizza>(store.orderPizza( "veggie" ) );
	cout << "We ordered a " << pizza->getName() << std::endl;
    return 0;
}